Surface sediment facies distribution and holocene stratigraphy of the Northern Great Bahama Bank

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Surface sediment facies distribution and holocene stratigraphy of the Northern Great Bahama Bank

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Title:
Surface sediment facies distribution and holocene stratigraphy of the Northern Great Bahama Bank
Creator:
Cargill, John G. 1972-
Place of Publication:
Tampa, Florida
Publisher:
University of South Florida
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Language:
English
Physical Description:
viii, 152 leaves : ill. ; 29 cm.

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Subjects / Keywords:
Facies (Geology) -- Great Bahama Bank ( lcsh )
Geology, Stratigraphic -- Holocene ( lcsh )
Sedimentation and deposition -- Great Bahama Bank ( lcsh )
Dissertations, Academic -- Geology -- Masters -- USF ( FTS )

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General Note:
Thesis (M.S.)--University of South Florida, 1996. Includes bibliographical references (leaves 85-90).

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University of South Florida
Holding Location:
Universtity of South Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
023507671 ( ALEPH )
37202437 ( OCLC )
F51-00123 ( USFLDC DOI )
f51.123 ( USFLDC Handle )

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SURFACE SEDIMENT FACIES DISTRIBUTION AND HOLOCENE STRATIGRAPHY OF THE NORTHERN GREAT BAHAMA BANK by JOHN G. CARGILL, N A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science Department of Geology University of South Florida December 1996 Major Professor: Richard A. Davis, Jr. PhD.

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Graduate School U niversity of South Florida Tampa Florida CERTIFICATE OF APPROVAL Master's Thesis This is to certify that the Master's Thesis of JOHN G CARGILL, IV with a major in Geology has been approved by the Examining committee on September 12 1996 as satisfactory for the thesis requirement for the Master of Science degree Examining Committee: A. D /l&i s Jr. Ph. D. {;;> I -i?e'mbe?: Lisa Robbins, Ph.D Mer:hber : #eter J Harries, Ph D

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ACKNOWLEDGMENTS Many thanks to Dr. Richard A. Davis, Jr. for taking me on as a student and supporting me financially during the course of this study Thanks also go to m y other committee members, Dr. Lisa L. Robbins and Dr. Peter J. Harries for their insightful comments and direction Most importantly, I would like to thank my committee for their patience and understanding near the end of the project. I wish to thank members of the Coastal Research Laboratory who assisted in sample collection in the Bahamas including David Ufnar, John Pekala, Peter Sedgwick, Jennifer Kling Darren Spurgeon, and Amy Welty Thanks also to Jen Ufnar Lara Niccosia and Greg Whittle for helping out when we needed more hands. I want to thank the rest of the Coastal Lab, as well, for their pat i ence through the never-ending data processing. Most importantly I owe thanks to my parents, sister and grandmother, who never gave up on me Their encouragement motivation and faith was the only thing that stopped me from giving up at times. My friends too, deserve thanks Especially Ken and Heidi who always listened when I had something to complain about, and were always willing (almost) to go out for a beer when it was needed. Thanks also to m y friends in North Carolina, especially Bryant and Jason, who never doubted that I would finish, and saved me a place to live when I did.

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TABLE OF CONTENTS LIST OF TABLES ..... .. .... ........ ........... ................... ... . . .. ... .. ... ... ...... .................... 111 LIST OF FIGURES... .. ... .................. ...... ...... .. . . .... .... . .. . ... .... .. ....... .. ... ... ... ... .. ...... IV ABSTRACT. ...... .... .......... .. ................................... .... . .. .... ... .. .. .. ... .. .. ....... . ... .. . . .... VI INTRODUCTION. ......... . .... .. . .. ... .. .... .. ........ .... .. . . ...... .. .... ... .. ........ . . ... ...... ... ..... ... .. 1 Objectives and Significance ... ............... ............. .... .... ....... ....... ... .. ... ............. 2 General Setting and Geology.. ....... ...... ...... .............. ........ ........ ............ ........ 3 Study Area... .... ... . ............... ...... .... ....... . .. ......... ... .... ..... ........ ........ ... .... .... .. 5 Previous Research ....... .............. ................. .. ... ............. .. ...... .... .. ... .. ... ....... ... 8 Surface Sediments and Facies Distribution .... ....... .. . ........ .... ..... .... 8 Stratigraphy and Sedimentary Facies........ .... ........ ... .... ....... ... . . ... 11 METHODS ... ...... .... .... ..... .... . .......... ... . ..... .... . . ... .......... .... ........ ... .. ....... . . . . .. ..... 14 Field Methods. . .... . ..... ... .. .... . . ... .. ... .......... .. ..... .. . .... .. .. ...... .. .. ... . .. ... ... . 14 Surface Sampling .. . . ..... .... .... . .... .... .... .... ................. ............... ... .. 14 Coring Methods ... .. .......... .... . .... .... ...... ..... .. .. ... .. ... ... .... ... ... ... ....... 16 Laboratory Methods... .. ... . ....... . ..... . .. . . .. ... .... ... .. ........ ........ ... . .... .... .... ... . 18 Surface Sediment Analysis .. ... .. ... .. ... .......... .. ........ . ... .. .... ......... .... ....... 18 Sampling from Underway Samples ......... ... ... .... ................... 18 Wet Sieve Analysis .... .... .... ...... .... .... ... ........ ........ ... ... ...... 18 Dry Sieve Analysis ...... .... .. ... .... .... .... ...... ..... . ........................ 19 Thin Sections.. .. .... .... ...... .... .... ............. ........ ... ...... ... ............ 19 Point Counts.... .... ....... .... .... ........... ........ ........ .............. .. .... 20 Stratigraphic Analysis... .... . .... ....... .... ........................ ... ... ..... .... .... 21 Core Logging and Sampling... . . .... .... ... .. ... .... .................... . 21 Core Peels... .... .... . .. ... .... .... . .... .... .... . . .... ... ....... ..... ...... .... 22 Radiocarbon Dating .... . .. ... .... . .... .... ...... .... ....... .. ...... . ........... ...... 22 SURFACE SEDIMENT FACIES ....... .... .... .. ... .. ........ .. ............... .. ... ........... ..... ... ...... 24 Distribution of Sediment Grain Types .. .... ...... .. .......................... .. ... ... .......... . 24 Distribution of Sediment Textures.. ...................... ... .... .............. .. ...... .. ...... ...... 32 Surface Sediment Facies.... ......... .. ... .. ....... ........ ............ ...... ....... ... ...... .... ..... 4 2 Distribution ofFacies ........................ ......... ..... ........ ...... .. ..... .. ... ........ ... . ..... .. 46

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HOLOCENE STRATIGRAPHY ... . .... .... .... .... .... .... . .... .... . ..... ...... ... . . . . . . . ..... 49 Core Sediment Facies ...... .. ... .. ... .. ... ... ............. ... ........................ ... .... .... ... ..... . . 49 Lithified Sediments ........................ . .... ....... ... . . ........ . ............. ......... 49 Hardgrounds .... ......... .... .. . . .... ......... .... .... . ...... ... ... ...... . ............. ... 51 Sediment Facies Distribution Through Time ....... ..... .. . ... . . . ........ ......... ........ 55 DISCUSSION ................... . ........ .. .... ..... ... .. ............................................... ....... ......... 68 Potential Contribution of Mud by Whitings ............. .... : 68 Texture and Composition ... ....... .... ... .. .... .... ... .. . . .... ... .. . . . . ... .... ... ....... . . . 73 Facies Distributions ... ................................................................... . ..... . ..... .... 76 Holocene Stratigraphy ...... .... ....... . .... ............................... .. ........ .... . . . . ... ..... 79 CONCLUSIONS ................ . ........ .... ...... . ....... .... .................... . ....... ....................... . 83 REFERENCES ... .... . ...... ...................... .... ......... . .... .... . ...... ................. . ...... . . ... ....... 85 APPENDICES .. ..... ...... .. . ..... .......... ... . ....................... .... ...... . ... .... ... . .... ....... ........ 91 APPENDIX 1. CORE LOGS .... ........... ... .. ........... ....................... ..... ..... ... .... 92 APPENDIX 2 STATISTICAL DATA FOR SURFACE AND CORE SAMPLES .... .... .... .... .... . . .... .... . ...... ... ........... .... ....... ........ l26 APPENDIX 3 POINT COUNT DATA FOR SURFACE AND CORE SAMPLES .......... ... ........................... ... .... . . . . ... ... .. .... ..... . l34 APPENDIX 4 PETROGRAPIDC DESCRIPTIONS FOR LITHIFIED SEDIMENTS AND HARDGROUNDS .... ..... ............... ... . . ISO 11

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LIST OF TABLES Table 1. Sources used by Enos (1974) in compiling surface sediment facies distribution within the study area ................. . .................... . ........... ... ... 11 Table 2. Radiocarbon dates for hardground and lithified sediment samples ... ....... .. 23 Table 3 Summary of criteria for the designation of facies on the northern Great Bahama Bank . . .... .... . ... . ......... .... ...... . . . ..... . ... ..... .. ... ... ...... ... . 44 Table 4. Summary of mud accumulation rates from individual cores, including and excluding mud c ontained in pellets ...... .... ............... ... . ...... .... .. . .... . 70 Table 5 Statistical data from sedimentological analyses on all surface and core sediment samples . ..... .... . .... ............ . ...... ........ ............ ... .......... 127 Table 6 Point count data for all surface and cor e sediment samples .... ..... ... . ...... US lll

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LIST OF FIGURES Figure 1. Chart showing relation of the Bahama Islands to neighboring land and ocean channels........ .... . ........ ... .......... ...... .... ................. .... ........... ... .... ... 4 Figure 2 Bathymetry map of Great Bahama Bank showing study area. ..... ..... .... ..... 6 Figure 3 Surface sediment facies distribution. .... ..... . ....... ..... . ......... .... ......... ........ 1 0 Figure 4 Surface sediment map of the Great Bahama Bank and vicinity... . ..... . .... 1 2 Figure 5. Locations and sample numbers for all sediment samples. ...... ... ......... .. .. .. 15 Figure 6 Locations and sample numbers for all cores from this study, as well as those used from Boss (1994)....... . . . ... .......... .... ... ........ ... ....... ..... .... ...... 17 Figure 7. Photographs of common grain types...... .... . ................... ....... ................ 25 Figure 8. Contour map showing the distribution of pellets within the stud y area ..... 26 Figure 9. Contour map showing the distribution ofmicritized grains within the study area......... ............................... ................... ... ..................... ...... ......... 28 Figure 10. Contour map showing the distribution of grapestone grains within the study area .................. . .... .... .............. .... .......................... ............. ....... ..... . 30 Figure 11. Contour map showing the distribution of Halimeda grains within the study area...... .... ...... ............ . . .... ...... ............................. ......... ............... 31 Figure 12. Contour map showing the distribution of bivalves within the study area .......... .... . ........... . ........... ......... ..... ..... ............ ...... ........ ... ..... .. ............ 33 Figure 13. Contour map showing the distribution of for ams within the study area.... 34 Figure 14. Contour map showing the distribution of mud within the study area ... .... 36 Figure 15. Contour map showing the distribution of gravel within the study area ...... 37 lV

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Figure 16. Contour map showing the distribution of mean grain size within the study area ................... ..... ... . .. .... ..... .... . ..... .. ...... ........... .... ..... .... ..... . ..... 3 9 Figure 17. Con tour map showing the distribution of median grain size within the study area . . ... .... ........................... ...... . .... ..... ... . ... ... ... .... . ... .. . . ... ... .... 40 Figure 18 Contour map showing the distribution of sorting values within the study area ......... .... .... .. .... .............. .... .... .... ................ ........... .. ... ............... ....... 41 Figure 19 Contour map showing the distribution of skewnes s values within the study area .......... .. .... .... .... ... . .... .... ... ... ........ .. ... ........ .. .... .... ..... ....... .... .... 43 Figure 20. Surface sediment facies distribution for the northern Great Bahama Bank .... .... . ... . .... .. ....... ........... .... .... . ... ... ... ....... ........ ........ ... . ...... ....... 4 7 Figure 21. Photograph showing A) fibrous marine cement in a lithified sediment fragment, and B) freshwater blocky spar cements and neomorphism in a hardground sample................... .. ....... ........ ..... ............. 50 Figure 22. Map showing depth of hardground surfaces below the water surface as obtained from core and probe data .... .................................. ....... ....... .... 52 Figure 23 Map showing locations and radiocarbon dates ofhardground samples taken from cores... ............................ .... ... .................................................... 54 Figure 24. Index map showing locations of cross sections constructed across the study area ................................................................... ......................... .... ..... 5 6 Figure 25. Cross section A-A' ....................... .. .... .............. ................. ..... ............... ...... 57 Figure 26 Cross section B -B' ....... ................................................. ......... ...................... 58 F i gure 27 Cross section C-C' ....................... ............ ....... .............. ............. ................. 60 Figure 28. Cross section D-D' ............ ...... ........................ ............ ................................. 6 1 Figure 29. Cross section E-E' ........ ..................... ..... ................. ..... .......... .............. ........ 62 Figure 30. Cross section F-F' .............. ...... ..... ....... ............................... ... ... .......... ...... 6 4 Figure 31. Cross section G-G' ...... ................. ....... ............... ............ ............ .................. 6 5 Figure 32. Cross sect ion H-H' . .... ........ .......... ... ............... ............ .... ........ ... . ... .......... 66 v

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SURF ACE SEDIMENT FACIES DISTRIBUTION AND HOLOCENE STRATIGRAPHY OF THE NORTHERN GREAT BAHAMA BANK by JOHN G CARGILL, IV An Abstract Of a thesis submitted in partial fulfillment of the requirements for the degree of Master of Science Department of Geology University of South Florida December 1996 Major Professor : Richard A. Davis Jr., Ph.D. Vl

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Close scrutiny of surface sediment facies maps ofPurdy (1963) and Enos (1974a) for the Great Bahama Bank indicates fundamental problems in sediment characteristics as well as in methods and density of sampling and analysis. Textural and compositional trends examined on 154 surface samples and 30 vibracores from the northern half of the Great Bahama Bank resulted in a new surface sediment facies distribution map and the first detailed examination of Holocene stratigraphic trends for this area. Seven facies were recognized from surface and core sediment samples. The pellet facies is characterized by < 20% mud and > 40% pellets with variable amounts of true ooids and superficial ooids. The pellet/grapestone facies contains > 20% each of pellets and grapestones, with <5% mud. The pellet! Halimeda facies is typified by > 20% each of pellets and Halimeda grains, with < 20% mud. Similarly, the pellet/micritized grain facies contains > 20% pellets and micritized grains, and a mud concentration less than 20%. A Halimeda facies is characterized by < 5% mud, < 20% pellets and > 25% Halimeda grains. The pellet mud facies contains > 20% mud and > 40% pellets, while the mud facies contains > 50% mud. Lastly, the hardrounds are in situ Pleistocene rock, which are the result of subaerial exposure during the latest sea-levellowstand. Textural characteristics of surface sediments supports westward cross-platform transport in the northern portion ofthe study area, although some knowledge of the hydrodynamic conditions is necessary for accurate interpretations. Calculated mud accumulation rates of 8.4 cm/103 yrs and 9.5 m/103 yrs for two defined areas on the bank are within the range of rates calculated at specific core locations of0. 80 cm/103 yrs to 12.5 cm/103 yrs. Values increase when mud contained in Vll

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pellets is accounted for, and range from 8.1 cm/103 yrs to 24. 1 cm/103 yrs In addition total sediment accumulation rates of30 cm/103 yrs and 34 cm/103 yrs from this study fall within the range reported by previous workers for the area to the north. Mud accumulation rates of 108 8 g!m2/yr and 96 9 glm2/yr indicate that a maximum of8% of the carbonate produced by whitings is preserved in the Holocene stratigraphy. Abstract Approved: vp r 1 !C" ro 'Richard A. Dif.'i, Jr. PhD. Distinguished Research Professor, Department of Geology Date Approved : __ _____ Vlll

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1 INTRODUCTION The Great Bahama Bank is the most extensively studied carbonate platform in the world. Since the pioneering research of numerous researchers in the late 1940's and earl y 1950's (e.g. Illing, 1954; Newell, 1955; Newell and Rigby, 1957; Imbrie and Buchanan, 1965; Cloud, 1962), hundreds of papers have been published on many aspects of carbonate research throughout the Bahamas. As a result of these research efforts and the resulting wealth of knowledge gained on carbonate depositional environments the Great Bahama Bank has become the premier modem analog for many ancient carbonate sequences. Examples include the Cambro-Ordovician of the Upper Mississippi Valley and Michigan Basin (e.g. Davis, 1965, 1975; Smith et al., 1993) the Conocochea gue Limestone (U. Camb.) of eastern United States (e.g. Demicco, 1983), the Pennsylvanian of the mid continent (e.g Wilson, 1975) and the Cretaceous of Texas and Mexico (e.g. Fisher and Rodda 1969; Enos 1974b). Nevertheless, there remains a lot to learn about this carbonate platform. For example, Holocene stratigraphy of the inner bank has not been considered except through broad characteristics as revealed b y high-resolution seismic surveys in the north and northwest (e .g E berli and Ginsburg 1989; Wilber et al., 1990; Eberli et al. 1994; Boss 1994). Further, some ofthe original work on surface sediment facies (e. g Purdy 1963b) is broadly inaccurate. Consequently, additional effort is necessary not only in new areas

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of investigation on the bank (Late Holocene stratigraphy), but also to modify previous work on surface sediments in order to better characterize and define the nature of the Holocene stratigraphic record on the bank. Objectives and Significance 2 Understanding the origin of the sediments and the nature of the lateral facies changes on Great Bahama Bank is critical if this depositional system is to continue to be used in interpreting ancient deposits Illing (1954), Ginsburg (1956), Newell and Rigby (1957) Newell et al. (1959), Purdy (1963a,b) Taft and Harbaugh (1964), and Shinn and Ginsburg (1964) among others, have all described the sediments on the Great Bahama Bank and provided a basis for understanding their origin and the processes that determine their distribution As a result of these studies as well as others across the Bahamas, several maps have been published showing facies distributions (e.g. Purdy 1963b ; Purdy and Imbrie, 1964 ; Traverse and Ginsburg, 1966 ; Ball 1967) Enos (1974a) compiled sediment data from 18 principal sources and constructed a map covering the entire Bahama Bank. All data used by Enos were compiled from sources published prior to 1968 (e .g. Illing, 1954 ; Newell, et al., 1959 ; Cloud, 1962 ; Purdy, 1963b ; Purdy and Imbrie, 1964 ; Traverse and Ginsburg, 1966; Ball 1967). The most widely cited map ofthe surface sediment distribution on the bank (Purdy, 1963b) is not entirely representative ofthe sediments present and is based on only 218 sediment samples across the entire platform. One of the primary objectives of this study was to

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resample the northern Great Bahama Bank in a systematic manner in order to produce a more accurate and reliable surface sediment facies map 3 Our knowledge of the Late Holocene stratigraphy across the bank is virtually nonexistent. A few studies of thin three-dimensional sedimentary facies have been conducted, but are limited to the intertidal and supertidal mud flats of northwest Andros Island, and to the northernmost portions of the bank (e.g. Black 1933 ; Ginsburg and Lowenstam, 1958 ; Ginsburg, 1960; Logan et al., 1964; Hardie, 1977; Boss 1994) With the exception of vibracores taken in the north (Boss, 1994 ), the depth of sediment examined on the open bank area has been limited to that penetrated by the box cores which were used for sediment sampling (Imbrie and Buchanan, 1965). The other major objective of this study was to take vibracore samples through the entire suite of Holocene sediments on the bank to establish stratigraphic relationships among these lithofacies. General Setting and Geology The Great Bahama Bank is the largest of the carbonate platforms east and southeast ofthe Florida peninsula (fig.l). It covers approximately 96 000 km2 and comprises one of the most extensive modem-carbonate depositional systems in the world There is no terrigenous input to the area; the pure carbonate sediments on the open bank are a combination ofbiogenic grains, ooids, peloids and micrite The bank is isolated by the many deep channels which define its borders. The fault-bounded margin slopes are at some places inclined at greater than 60 degrees, and extend to depths of more than 650

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TOR TUGAS o; ,, , : / C!,;Y : . . . .. .;a ........ CA'fS ,... '................. ....... -!40 ,, .. ? ISL Of PIMES 7 6" WATLII'O I 24 Qa II'AGUA 1. Figure 1 Chart showing relation of the Bahama Islands and banks to neighboring land and ocean channels. meters (Jones and Desrochers, 1992). Banktop water depths range up to 15 meters but are generally less than 6 meters. Water temperatures range from 27C to 32 C, with salinities varying from near normal (34psu) at the margins to almost 46psu on the bank interior (Jones and Desrochers, 1992). Pleistocene carbonate islands along the eastern margin create a barrier against cross-bank water circulation caused by the dominant easterly trade winds. These islands alternate along the bank margin with extensive ooid shoals (Ball, 1967) Winter storm winds come from the northwest, while winds generated by the westerly-moving hurricanes are highly unpredictable. Tidal range across the bank is low, about 0.8 meters at the platform margin, decreasing to about half that amount on the central platform (Tucker and Wright, 1990) 4

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5 Study Area The portion of the Great Bahama Bank which was sampled in this study covers an area of approximately 15,000 km2 (fig 2) Five latitudinal transects were completed at about 30 km spacings to ensure the best possible coverage during available ship time. The eastern portion of the field area extends to the shallow (2-3m) waters just off Andros Island Sampling in this area was limited to about 3 m water depth. In the west, sampling was contained within the interior of the bank at least 5 km from the bank margin. Northern and southern boundaries are marked by the 24 40 and 25' latitudes. These locations were chosen due to convenient starting (Bimini) and stopping (near Williams Island) points during cruises. Water depths over the field area are generally less than 6 meters. Depths extend to 14 meters northeast ofMackie Bank, in the north central portion of the study area (fig. 2). The western margin of the bank ranges in depth between the many small islands and cays before sloping into the Florida Straits Tidal influence within the study area varies geographically. Diurnal tidal currents from the Florida Straits in the west, which is the main axis of the northbound Gulf Stream, and the Providence Channel to the north, are oriented approximately normal to the edge of the bank These currents reach velocities between 25 cm/s and 100 cm/s, with water level fluctuations up to 0.78 m during spring tides (Smith 1940; Purdy, 1963a; Bathurst, 1975). According to Smith (1940) where these two currents meet (from the northern and western edges ofthe bank) the observed tide floods toward the southeast and

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.\.,,,, l '' 's t p . ,,,.,, r urr 0 N a u1i c31 n 1 i k!\ 30 0 .111 J.Lynclr 79" Figure 2 Bathymetry map of Great Bahama Bank showing study area (modified from Bathurst 1975). 6

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7 ebbs toward the northwest. Overall, tidal waters move in a radial pattern and are concentrated in tidal channels by cays, shoals, and reefs (Bathurst, 1975), with stronger flood than ebb currents In contrast, the central portions of the bank exhibit a reduced tidal influence perhaps negligible, as compared to the bank margins as a result of a phase lag in tidal oscillations between the northern and western areas (Smith, 1940; Purdy, 1963a). Smith concluded from his studies that the direction and velocity ofthe wind are more important than tidal currents in controlling water movements in the central portions of the bank. Because currents are controlled mainly by winds, Smith studied yearly wind records from the Bahamas in order to quantify main seasonal current changes His study indicated that in summer the predominantly southeasterly winds result in a steady westerly current across the central part of the bank (Smith, 1940). During winter, variable and more northerly winds cause currents to flow in a southerly direction. During periods of northwesterly gales, water is transported toward the east from the Florida Straits. In addition, hurricanes, although rare, are very effective in creating high velocity currents (Ballet al., 1967; Bathurst, 1975; Boss, 1994). As a result of the ever-changing wind driven currents on the bank, Smith (1940) concludes that water bodies have a relatively long (1 month or more) residence time on the bank. It has been noted by many authors that salinities progressively increase from the outer platform to the inner shelflagoon (e .g. Black, 1933; Smith, 1940; Newell, et al., 1959). North of Andros Island, salinity varies from 36 psu near the margins to 38 psu near the center of the bank (Newell et al., 1959). A mass of hypersaline waters exists

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8 west of Andros that shifts position in response to prevailing winds. Data suggests that salinity in this region ranges from 38 psu to 46 psu, with an average value close to 40 psu (e.g. Cloud 1955; Newell et al., 1959; Purdy 1963a). It has been noted that the hypersaline mass is maintained throughout the year and rarely moves off the bank. The cause is thought to be the combined effects of opposing tidal currents, shifting wind directions and the sheltering effect of Andros Island (Smith 1940 ; Purdy 1963a) Rainfall has an effect on salinity as well. Most of the precipitation in the Bahamas occurs during the period from May to December, thus lowering salinity during this period (Smith 1940; Newell et al., 1959) Finally, water temperature over the bank is very uniform at any given time. Due to the shallow water and thorough mixing by wind currents, vertical stratification is nonexistent except at the bank margins where mixing with ocean water is apparent (Smith, 1940). Bank-top temperatures can range from around 27 C in winter to around 32C in the summer. Daily temperature fluctuation, on the other hand, is on the order of 1 C, regardless of the season. Previous Research Surface Sediments and Facies Distribution Illing (1954) demonstrated that the sediments of the Great Bahama Bank consist of several types of particles composed predominantly of aragonite. He recognized precipitated ooze, oolite sand, fecal pellets, skeletal sand, and aggregate grains. Not long

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9 after, various studies were conducted to determine the distribution of each grain type (Newell, 1955; Newell and Rigby, 1957). Investigations into carbonate sediment types and distributions were numerous during this time, and several authors presented their own classifications and facies distributions (e .g. Newell et al., 1959; Purdy, 1963b). Distinct belts of ooid sand along the bank margins were discussed in detail by Ball (1967). Cloud (1962) investigated the grain size distribution of sediments across the entire bank and concluded that it consisted of 40% clay, 14% silt, and 46% sand He recognized the same grain types as other authors, and added work on mechanical characteristics, microbiology, and biochemistry of the sediments with special emphasis on the micrite. Purdy (1963a,b) conducted a study of the petrography of all sediments, defining five facies from 218 sediment samples that came from throughout the entire Great Bahama Bank. His facies included the coralgal facies, oolitic facies, grapestone facies, pellet-mud facies, and mud facies (Purdy, 1963b). He gave factors for the genesis and distribution of these five facies and produced the first extensive map of the facies distributions (fig. 3) which has, over the years, become the most widely referenced sediment distribution map ofthe Great Bahama Bank (e.g. Bathurst, 1975; Enos, 1983; Sellwood, 1986; Jones and Desrochers, 1992). Subsequent maps of the facies distribution on the Great Bahama Bank were published by Purdy and Imbrie ( 1964 ), Traverse and Ginsburg (1966), and Ball (1967). Up to this point in time, no regional map of surface sediment facies had been produced for the entire Bahama Plateau. Enos (1974a) recognized the need for such a map and compiled one (fig.4) from many reports on various parts of the region. His

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0 20 miles GREAT BAHAMA BANK Andros Platform cor a I g a I oolitic bv:,';.:.J grapestonel';... .:. < 4 mud pellet mud (?::;::_::.] SAMPLE LOCATION Figure 3 Surface sediment facies distribution (from Purdy, 1963) 10

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11 Author of Source Date Area Covered Illing 1954 Southeast Great Bahama Bank Newell, Imbrie Purdy, Thurber 1959 Andros Lobe Great Bahama Bank Cloud 1962 Andros Lobe Great Bahama Bank Purdy 1963 Andros Lobe, Great Bahama Bank Purdy and Imbrie 1964 Joulters Cays Great Bahama Bank Traverse and Ginsburg 1966 Northwest Great Bahama Bank Ball 1967 Northwest Great Bahama Bank Table 1. Sources used by Enos (1974) in compiling surface sediment facies distribution within the study area sources for the compilation which are relevant to this study are shown in Table 1 Because no two authors used the same classification scheme for the sediments (Enos, 1974a), all data were reclassified using Dunham's (1962) classification of depositional texture as a primary basis for subdivision At approximately the same time, Gebelein (1974) produced an updated version of the Great Bahama Bank surface sediment facies distribution map in a Geological Society of America Guidebook. Since 1974, there have been no further updates or surface sediment facies distribution maps published. Stratigraphy and Sedimentary Facies Except for fairly recent high-resolution seismic studies (e.g Eberli and Ginsburg, Wilbur et al., 1990; Eberli et al., 1994; Boss, 1994), little has been done on the Holocene stratigraphy of the Bahama Bank. Imbrie and Buchanan (1965) conducted the first published studies of the sediment bodies and their superimposed bedforms on the

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.'(.l' 1 h0 I 7 CARBONATE SEDIMENTS &r11ns11ne "ooo PBIIBIDidal \VS wmestGoe Pellellldal l t.llud Pelletotaai-Skelelal Fresh\Uie r II me mud Bounds lane reelslovsler-mmtlldl coral-coralline a1ua1 reelS NON CARBONAT E SEDIMENTS ff -.., 1 1 ...... I f ' ......,. I Lll ;\I IN I "). .. i ......_ I / .-:..:. < ',\ h v "' ( 0 1\. ) ;\. l l / 'Jj a ''\wu ( tTi . :::\. ...:." U p ' . .:., ,. '"' \ . Jerri uanous ellS lie su1mea1s .-:. / .. ...:. \ ( I q J ouarll m _!S_ Shelly m rl! sud ;, oreulc Manorm pear Euparrus .6USUII Um 0 100 .b-....J KM (N-S SCALE) 1 ' y ')) ) )r-1 ... lJ .. ) : I .. / . D II 50 180 (' : .,. ;., i l'lt r W t OJ.. 0 IJ:!:f. '"-. .;;<') I / -=.:, I ( <"G.' . I <. ( "'s: . ...... > . ' o ''\ o v . \ ... .... \ Sl ;\ r ,, . L.. /.. 'f < .. ' ,,.(' \ 8(1 .., / } .) ( \ ''""" :.,... -.. ' 1,lj .>.. --.. \ ;:,, .., )/ ;I .. ... , < I c \ / J ' 0 1 ) .,_;1 , .J:, ,'" 1 ,1.{ ;,, j .. _._f_ \II If..,$ \ \ 't _;_ '\.. I . F igure 4. Surface sediment map of the Great Bahama Bank and vicinity (modified from Enos, 1974). SUIUII MillS OS SAN f SALVADOR V f \ '260 -,..... N

PAGE 24

bank from air photos, visual inspection of the bottom, echo-sounding traverses, and 50 box cores. These authors classified avalanche ripples, accretion ripples, flat, swash surfaces, large-scale current lineations, bars, and irregular shoals. The stratigraphic extent of these investigations was limited by the depth of sediment which is retrievable through the use of a box core (about 0 5 m). Imbrie and Buchanan established various facies dominated by physical structures and others dominated by biogenic structures 13 Most recently, Boss (1994) determined through high-resolution seismic surveys that there is a general thickening of Holocene sediments from east to west across the northern Great Bahama Bank. Much textural and compositional data indicate that sorting increases in general to the west, as does the amount of nonskeletal material. General conclusions were made about banktop transport, which are consistent with known wind wave water movements across the bank. Further, Boss (1994) concluded from 16 sampled cores that sediment textures downcore are "remarkably uniform" and show insignificant variability from top to bottom.

PAGE 25

14 METHODS Field Methods Surface Sampling Surface sediment samples were gathered every two nautical miles along five transects during two research cruises (fig. 5). Methods used were underwa y sampling and grab sampling. Fifty-five (sample #1-55) underway samples were collected on a 1994 cruise. The pipe sampler was towed at boat speeds less than two knots, and sediment was scraped from the surface. Sediments were forced through the tube and collected in a Hubco Sentry sample bag, attached to one end. After being brought to the deck of the boat the sample bags were put into zip-lock bags for transport back to the laboratory. Eighty-two (sample #56 -137) grab samples were collected on th e 1995 cruise, due to the loss of the underway sampler. The boat was stopped at each sampling station. To reduce the size of the sample brought back to the lab, two 100 ml samples were taken from each grab sample. One was processed while the other was put into repository storage.

PAGE 26

N orthern G r e a t B a h a m a B a n k l I ... .l. S urf ace S edim e nl Samp l e L o c alio n s l .l. i , ._. ........... l++;<1-...._._,-l-j-<-......... _._...I .......... ... 1--B imin i I slan d s , 48. ... oo 61 62 63 61 6 8 69 10 11 n 13 ,, 76 . . . . . . 1 3 0 .J,. 101 10lfe "T 1 0 1 100 99 98 97 96 9S, 9 3 91 91 9 0 19 88 8 7 86 104 :t ... 20 .,,j, 78 .,. Ho II 0 Ol . . . i 4S, -re : o '! ':' z ; t z a 4 4 e 11 0+1 113 liS, 117 11! 121 12) 12S 119 ... i + n .,. 130 z. 131 + so 4 0 30 ,,zo 1 1 1-+ H .. . j . j . j J ) ... lS. O r a nge Caya 37 l , l G e 34 nJZJ I lO 19 28 2726 ZS el)l u 11 !" : ) 22 r 50 z l e M + S + l 8 + 9 1 0 11 T ,4 0 13 14 . 1'1 1617 . 19 1 8 l 71!'\X) I Fi g ur e 5 L oca tions and sampl e number s f o r all sur f ac e s e dim ent samples. 15 2 0

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16 Coring Methods Vibracoring methods modified from previously published methods (Lanesky et al., 1979 ; Stone and Morgan, 1992), were used to obtain 30 cores along 5 transects across the Northern Great Bahama Bank (fig 6). Aluminum irrigation pipe 7.6 em diameter of between 6 and 9 m long were vibrated into the sediment by a cement settler powered by a 5-hp gasoline engine, off the stem of a 71 ft research vessel, the RV Bellows Cores penetrated to first refusal which was either a hardground surface or a layer of impenetrable shell or rock debris. As a result of deeper water on the bank, it was necessary to send two SCUBA divers down to assist in retrieval of the core. After penetration the divers proceeded to cut the pipe near the sediment/water interface, measure the ins i de and outside edges for the computation of compaction, and plug the end o f the pipe with a specially designed rubber stopper. A chain was wrapped around the pipe and attached to the end of a winch. When the divers signaled, the winch was s tarted, and the core was retrieved. A waiting diver capped the bottom of the pipe as soon as it broke surface to prevent loss of sediment from the bottom Once on deck the plug was removed, the end was capped, and the core was secured for transport to the laboratory.

PAGE 28

Northern Great Bahama Bank B imini I slands IJJ15 -Itl ' J I OX-02 G88-6 & 7 883-6 883-t l)JJ5 -1'1 40 STA-2 30 .883-5 H7tt -U'J 20 STA-3 STA-4 Core Localions Core l ocations from c u rre n t prnjc<:t Cor e locations fro m Boss. 1994 883-2 8834 K51h-tH lfXJimJ, "III\ ---------r-883-3 Juu lt crs C a y 17 lO c::::M c:::2M G88-5 G88-4 G88 G88-2 0 Naullral Mll6 40 10 G88-t c=-c::a Orange Cay 0 882 882-2 883-10 50 882 40 7/IXI I 50 883-9 8824 STA19 STA-20 4 0 883-8 30 8827 882-5 882-6 Williams Island ')lllK-115 20 883-7 7><'1 X l I Figure 6. Locations and sample numb ers for all cores from this study as well as those used from Boss (1994). N 1

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18 Laboratory Methods Surface Sediment Analysis Sampling from Underway Samples. Because the surface samples collected through the use of the undezway sampler were several kilograms in weight, it was necessary to obtain a smaller, yet representative sample to analyze. The nature of the sampling process could bias the sample, therefore, small portions of the kilogram sized sample were taken from each end and the middle, then combined Mud content of the small sample was compared to the mud content of the remaining sample Comparisons were made between three samples of differing location and mud content. Results of each set compared were within one percent of each other It was decided that one percent was an acceptable error, th e refore all other samples were subsampled for analysis. Wet Sieve Analysis. Every surface sample was wet sieved in a 63 micron sieve before any further analysis took place Two sieves were constructed using pieces of 12 inch diameter PVC and copper mesh The large size of the sieve is necessary due to the combination of the mud content and the large samples collected and analyzed ; each sample was up to 4 oz. (1 00 ml). Distilled water was utilized in the wet sieving process After each sample was placed in the sieve, up to 17 liters (4.5-gal.) ofwater was washed through the sample and collected in a 18. 9 liter (5-gal.) paint bucket. The sand and gravel fraction which remained in the sieve was washed into a 1 000 ml beaker and dried in an oven at about 70C. The mud was allowed to settle in the bucket for a maximum of 4 days It was determined through the use of a pyncnometer that the weight

PAGE 30

19 of suspended material after 4 days was less than the mechanical error of the scale used for weighing Any sediment still in suspension was sampled for possible future research ; the remainder was disregarded. A tygon tube was used to siphon as much wate r a s possible without disturbing the sediment on the bottom of the bucket. The mud was then washed into a pre-weighed 1000 ml beaker as a slurry and dried in an oven at around 70 C After drying both sand and mud fractions were weighed thus allowing the calculation of weight percents for each surface sample Dry Sieve Analysis. The sand and gravel fraction of each surface sample was subjected to sieve analysis at half phi intervals from -3.0 3 5 The samples were placed in the rack of si e ves and shaken in a Ro-tap for 3 minutes This gave sufficient time for the grains to sort, yet not allow disaggregation of poorly cemented grains (i e grapestones o r lithic fragments) Contents of each pan were then weighed Statistical analyses were computed on the data to determine mean grain size, median grain size, standard dev iation skewness and kurtosis Results of these analyses are summarized in Appendix 2, and aided in establishing the surface lithofacies Thin Sections. Thin sections were prepared in order to perform compositional analyses of sediments. Fiberglass boat resin was mixed with a small portion of the sand and gravel sized sediment, which was put i nto an ice cube tray mold Before the resin set, samples were placed in a small vacuum for about one minute to aid in the release of air bubbles U pon removal of the molds from the vacuum they were allowed to dry under a ventilation hood, then removed from the mold as a rock."

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20 A longitudinal cut was made on each rock with a thin-sect i oning saw It was then on a glass plate with a 200 / 220 grit mixture and smoothed with a 400 grit resin. Petrographic slides were glazed before the sample was mounted with a clear epoxy At this point standard thin sectioning methods were utilized. These are described in detail by Carver (1971) Overall 295 samples were thin sectioned and analyzed Point Counts. All petrographic examinations were conducted with an Olympus petrographic microscope Because grain type identification can be somewhat subjective, some basic criteria were established to insure that the counts were uniform. Categories included pelle t s ooids, micritized grains of unknown origin, grapestones Halimeda fragments forams bivalves gastropods echinoderms, coral bryozoans, lithic fragments and unidentified grains Identification of allochems such as forams, bivalves gastropods echinoderms corals and bryozoans is stra i ghtforward. References such as Adams, Mackenzie, and Guilford (1984), and Scholle (1978) were utilized for questionable grams A problem arose however, when distinguishing between true ooids, superficial ooids and pellets At times it was difficult to identify concentric laminations within a well rounded grain So as not to spend long periods of time debating the issue, the following criteria were followed. If no laminations were read i ly identifiable the grain was called a pellet. If the gra i n had only a surficial coating, they were identified as the original grain type so that an attempt could be made to identify areas of sediment production on the bank This is in opposition to other authors who may call these grains

PAGE 32

21 surficial ooids If more than a surficial coating was observed, the grain was classified as ar:J. ooid. Problems were encountered identifying other grains as well Many allochems degrade in the bank environment, they are abraded, and are bored by other organisms. For example, Halimeda is typically degraded by such processes. There is an abundance of Halimeda in the sediment, but this is not reflected in all of the point count totals. If the grain was rounded, yet some of the original structure was identifiable, the grain was classified based on that original grain type. In the case of many grains, the internal structure was present, but could not be identified. When this occurred, the grain was classified as a micritized grain of unknown origin. It is believed that many of the Halimeda fragments in the sediment fall into this category. Thus, results of Halimeda content may be slightly misleading Stratigraphic Analysis Core Logging and Sampling All cores were cut into 1 m sections for storage and ease of handling The sections were then split by placing them into a wooden trough and cut lengthwise with a circular saw, penetrating only the thickness of the aluminum pipe. After being photographed for logging purposes, each section of core was stored at room temperature in a plastic bag. This was done in order to retain moisture and sediment cohesiveness More detailed logging of cores was carried out by examining sediment composition, textures, structures, fossil content, location and the lithofacies of hardgrounds. Sampling of cores was conducted at each visible lithologic change, or at

PAGE 33

22 0.4 to 0.5 m intervals, depending on changes seen with a hand lens. Care was taken not to use material close to the walls of the core pipe to minimize contam i nation by sediment from different portions of the core transported down during the core retrieval. Further this minimized the incorporation of aluminum shavings from the splitting procedure. Graphic representations of all cores are provided in Appendix 1 Core samples were subjected to the same analyses as described for surface samples, including wet and dry sieving, thin sectioning and point counting. Core Peels. Core peels were attempted on four sections of core in order to identify sedimentary structures not readily v i sible within the core. Cheese cloth was placed over the core, then covered by a fiberglass resin and hardener. The resin soaks through the cloth and into the sediment. Once dry, the cheese cloth is removed, along with sediments from the core, then rinsed with water to remove any excess Normally, structures such as bedding, imbrication and grain size trends can be seen better in a peel than in the core itself. No structures were evident in any of the core peels, however Although others have achieved successful from this procedure on Bahamian cores (e. g. Major et al., in press), it i s believed that bioturbation is too prominent on the bank for any structure to be preserved Radiocarbon Dating Radiocarbon dating of five samples was conducted by Beta Analytic Inc in Miami, Florida These included 4 hardground samples and a sample of lithified sediment from within a core. Samples were subjected to an acid etch, in which they were first

PAGE 34

23 washed in deionized water to remove any debris They were then crushed and subjected to. HCl etches to eliminate secondary carbonate components before being analyzed in a scintillation spectrometer. Conventional C14 ages ofthe samples are summarized in Table 2. As can be seen, all ages reported for hardground samples at the bottoms of the cores are late Pleistocene in age, while the lithified sediment sample is Holocene Sample Location Conventional c Age STA-2, bottom of core 21,330 + / 150 yrs BP BB2-4 bottom of core 28 630 + / 260 yrs BP BB2-5, bottom of core 18,5 7 0 + / 140 yrs BP BB3-3 within core 3,530 + / 50 yrs BP BB3-7 bottom of core 30,400 + / 330 yrs BP Table 2. Radiocarbon dates for hardground and lithified sediment samples

PAGE 35

24 SURFACE SEDIMENT FACIES Distribution of Sediment Grain Types Fecal pellets are the most common grain constituent observed in the surface sediment samples. They are formed through the ingestion and subsequent excretion of carbonate material by many marine organisms, and appear round, elliptical, or rod-like in shape. Pellets contribute as much as 84% to the sediment in a western portion of the study area, and less than 30% in the northeast comer. Relating pellets to the organisms which produce them is not possible, as many different animals produce very similar pellets However, according to Bathurst (1975), an important contributor is a polychete worm, Armandia maculata, as well as many other worms gastropods and shrimp species which graze on the organic rich floor of the bank Figure 7 A shows some pellets in thin section. They are all sand sized and exhibit no internal structure. As can be seen, the areas just west and northwest of Andros Island have the greatest concentrations of pellets, whereas percentages decrease to the northeast and southwest (fig 8). Ooids can be classified in three categories: 1) true ooids, 2) superfic ial ooids, and 3) pseudo-ooids (Tucker & Wright, 1990). Pseudo-ooids contain no concentric laminations, superficial ooids contain only one lamination, and true ooids contain 2 or more laminations (Tucker & Wright, 1990) True ooids are virtually absent in mos t

PAGE 36

. I 1mm ..,' ... ... 25 B (( ,. --..::-. F_,;, .1mln Figure 7 Photographs of common grain types. A) pellets B) ooids C) micritized g rains of unknown origin, D) grapestone E) Halim e da, and F) foraminifera.

PAGE 37

Northern Great Bahama Bank Distribution of Pelle t s Surfn< < fro m urr
PAGE 38

27 of the study area. Only two samples contained percentages of ooids greater than 11%. Both occur in the western portion of the study area along the bank margin. Figure 7B shows some examples of true oo ids. Ooid concentrations from this study contradict findings by other authors. For example, Purdy (1963b) reported over 60% ooids for the same areas where less than 10% were found in this study Purdy reported over 90 % in other locations as well. Superficial ooids, on the other hand, were more common Data do not reflect this, however, because superficial ooids were classified as the original grain type in this study. Purdy (1963b) included surficial ooids in his tabulation of ooid grains, thus resulting in the large differences within the same geographic areas. Data do however, demonstrate that true ooid formation is occurring only in i solated areas along the western margin of the Great Bahama Bank, whereas precipitation of micritic rinds around other grains is more widespread (Newell et al., 1960). The micritization of grains in the Bahamas has been documented by several authors (e.g. Purdy, 1963b; Bathurst, 1966, 1975; Boss, 1994). Micritization is cau sed by the boring activity of non-calcareous algae and subsequent infilling of bores with micrite. Because total micritization of grains is time dependent, one can obtain a relative residence time for sediments within an area (Bathurst, 1975; Boss, 1994). For this reason, totally micritized grains were tabulated from point counts Examples of micritized grains can be seen in figure 7C, and their distribution is shown in figure 9. A 20% contour line extends through the center of the bank to the southwest. West of this line, composition is le ss than 20%. East of this line, two areas contain over 30% One of these areas is in the southern portion of the study area, while the other is in the northeast

PAGE 39

Northern Great Bahama Bank Distribution of Micritized Grains of Unknown Orioin b S urface s a m ple s from current project C o r e dat a from c u rrent project l Data from Ho ss. IY I ---------, ___ _ .. __ 1 _ 0 I / I .. . . . Williams Island ?X'IKI I I Kllomettrs C ont o u r mtcn al = I 0'1 N r Figure 9. Contour map showing the distribution ofmicritized grains within the study area Contours are in percentage

PAGE 40

29 comer. Percentages decrease further to the east (fig. 9) The northern portion of the study area, along with much of the area to the north studied by Boss (1994) contains the highest concentrations of grapestones Grapestones, by definition, are clusters of carbonate sand grains cemented by micritic aragonite (Bathurst, 1975) (fig. 7D) Gebelein (1975) describes in detail the formation of grapestone grains from binding by forams and algae to the recrystallization of grains from Mg-calcite to aragonite. Areas where grapestones form and accumulate are marked by uneven physical water energy conditions with periods ofbottom stability interrupted by periods of bottom mobility These water conditions prevent lime mud accumulation, and promote recrystallizat ion of grains to aragonite (Winland & Mathews 1974). Grapestone concentrations range from zero up to 52% within the surface samples over the study area (fig. 10) Deposits trend northwest/southeast across the northern portion of the bank, coincident with cross bank currents described by Boss (1994). Also, sediments along the western margin of the bank contain grapestone concentrations up to 10% Their presence may be the result of higher current velocities which are necessary for the formation of grapestones, and are present in this region (Gebelein, 1974) Two portions ofthe study area show concentrations of identifiable Halimeda fragments within the sediment of greater than 10% (fig. 11). Abundance within these zones, which occur at the northeast and southwest comers of the study area, increases to over 30%. In addition, individual samples in the north and northwest contain concentrations greater than 20%. Examples of Halimeda grains are shown in figure 7e. Visual inspection of the bottom by divers during core extraction in the southwest

PAGE 41

Northern Great B a hama Bank Bimini i I I I I I ,. i i I Dis trib u t ion o f Grapestones Sur fatc smnplcs fr o m currenl project Core da1a fr o m c urrcnl project lJa t a f ro m Hoss. I 'JlJ4 30 { ---. ,,,; : ...... ______ i ............. -- I I I I Joulters Cay I . . . . ..... I I 10 0 .. I / I ... ;. .. . . . .. I I I I i I I .. I 1 I I I 7'J'IM1 Wi lliams l s l a ud ?X'IMI I I 30 u 20 c=w r=w t=M c::::a Nnullooll\ lllos 0 40 r=w r==w c::a c::::M Kilumrtrrs N I F i gure I 0 Con t our m ap s h owi n g the distribution of grapesto n e grains within the stud y area. Co n tours are in p erce nt age.

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Northern Great Bahama Bank Distribution of Halimeda Surface samples from currcnl projecl Core dala from curr en l projecl l IJala f ro m Hoss. 1994 I I I I I I I I 31 I ------1 --r----, i ---------------------------i---------------------Bimini Islands 1 I \ \ I \ I l I I I I I I 1 I .. i 0 I l l I A 10 ' . .. . . . . A I ,. . ..... ......... I I I I I I I .... .... --Joulters Cay l 1------------------------------! 0 .. / 20 / \ \ \ Williams Island I \ I I I 0 20 r=w r=w c:::::& L:::::::. Nauli
PAGE 43

indicates a much higher concentration of living Halimeda than noted in an y other area investigated Further, high (25-30%) concentrations of Halimeda fragments persist downcore to recovered depths of 1 2 m and 2 0 m in the southwest and northwest respectively 32 The distribution ofbivalves within the surface sediments is variable The most commonly encountered identifiable shells or shell fragments consist of the following molluscan species : A e quipecten sp Area sp., Lithophaga sp and Olivella sp ., Laevicardium sp. Lucina sp., Chione sp Tellina sp., and Trigonocardia sp Very few trends in bivalve distribution were found Concentrations range from zero to 22 % with most samples containing less than 10% Figure 12 shows two portions ofthe study area which have consistent concentrations greater than 10% As was the case with the bivalves concentrations of foram s within the samples are variable Two small areas, one in the northeast and one in sou thwest h a ve v alues of greater than 10 % (fig. 13), with the highest concentration in an y surface sample being 19%. Petrographic examination indicates that the majority of forams are peneroplids and various other b e nthic varieties The forams range in size from medium sand to coarse sand Figure 7F shows a sample with a relatively high content of forams. Distribution of Sediment Textures The term mud, as used here, defines all particles less than 63J..L, including micrite small pellets and skeletal debris Concentrations of mud within the study area show very

PAGE 44

33 Northern Great Bahama Bank Dis t ribution of Biva lves Surface sa mples from curr ent project Core d a t ; 1 fro m project Data from H oss. 1 9'J4 I I I I -..... -----..... --------_ .. __ -------------------.... -----+----------------o I :C:_ ..... . I I I I I I I I I I ......... <10 10 '-..:.___ . . . . ... J o ultcr s C a y \) .. . . . . . . . .. .. I W illi am s I s land 0 0 0 I I I I I 0 t::IIIA c:::::M Nuuliratl 1\' lilf' s N 1 Figure 12. Conto ur map showing the di s tribution of bivalve grains within th e study area. Co ntours are in perc e nta ge 20

PAGE 45

Northern Great Bahama Bank I 211u u I Distribution of Foraminifera Surface s mnple s from cu rr ent projet t Core data from current project Dnta from Boss. I 994 34 I i ---------------------------{--------------------Bimini Islands I I I I i r . . !# : J I I I I I . <10 I . . . . . . . . I I I I I I I J o u ltcrs Cay 0 0 0 0 .... . 1 I I I ,---. 10 I W illi a m s ls l n n d 1 I I I I 7X'IW> ) I 0 c=-c::. Nuutl
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35 distinct trends (fig. 14). There is virtually no mud accumulation in the north and west where tidal currents have a greater influence, but the abundance increases toward the center of the bank, into a bullseye located west/northwest of Andros Island. This bullseye is coincident with the area of the Great Bahama Bank in which most occurrences of whitings take place (Tao, 1994). Concentrations here are greater than 50%, but les s than 60%. Another interesting feature seen in the map of mud distribution occurs directly west of Andros Island, and stretches about 35 km southwest. A trend is defined by the 5% contour, in which little mud is present. This same feature is evident in several other maps of textural trends (see figs 16, 18 and 19). As is the case with many of the compositional and textural parameters gravel content is variable over most of the study area. Figure 15 depicts an area in the center of the bank which contains consistently higher amounts of gravel within the surface sediments Much of this area is consistent with mud concentrations of between 20% and 50%. Examination of sediment samp le s from within the 2% contour indicate that cerithid gastropods are the coarse component. The only other trend is in the north/northeast where concentrations up to 6% of gravel are the result of large grapestones, large Halimeda plates, and bivalves as is evident from their distributions (figs. 10, 11 and 12). Mean grain size represents the average grain size of a sample, which in this study is the average grain size of the combination ofthe sand and gravel portions Text ure s within sand and gravel deposits are more useful in determining relative levels of energy in carbonate environments than mud content. Mud is produced on the bank in many ways, including biological breakdown of grains, grain disintegration, and precipitation

PAGE 47

Bimini I s land s Northern Great Bahama Bank Distribution of Mud s amples from c urr e n t projec t Core d ata from c urrent proj ect lJat a fr o m Hoss. llJlJ4 . . . . . I -------i--1 I I I I J oulters Cay O 0 0 0 36 0 20 Na uti
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Northern Great Bahama Bank Dis tribution of Gravel Sur1'acc s aonplc s from curn:nl projecl Cor e dala from currcrll projccl Oala from H oss. IW4 J o u hcrs C ay b 0 0 0 I I I I I I I I I '1 I 37 0 !0 c:::::a c::::a Nnurlcnl 0 411 C'dW ,.......... c:::M 1\.ll onlt'lt-I"S .. . William s I s land 7>1'111 I I Figure 15 Contour map showing the distribution of gravel within the study area Contours are in percentage. N i

PAGE 49

38 (Tucker & Wright 1990). As a result, the distribution of mud is not necessarily indicative of energy levels in the depositional environment. This is especially true in the Bahamas For example, Bathurst (1975) points out that large areas ofthe Bahama Banks are covered in subtidal microbial mats which have stabilized the sediment enabling it to withstand current velocities as much as five times as high as those eroding nearby sediments lacking the microbial cover. As can be seen in figure 16, the mean grain size of surface samples falls within two major ranges Medium sand sized grains dominate the northern and westernmost portion of the study area, whereas the southern portion is dominantly fine sand Several smaller zones are evident including coarse sand in the northeast comer, and medium sand in the southeast and south (fig. 16). Median grain size is that grain size in which the 50th percentile lies within a sample. As for other characteristics analyzed the values introduced here are for all grain sizes coarser than (sand and gravel) Most of the study area has a median grain size between and (medium sand). Three small zones of coarse sand sized values are evident in the northeast, and a large area with median grain sizes between and 3 (fine sand) lies in the southern half of the study area (fig 17) Values of standard deviation or sediment sorting, are represented in figure 18. A large area in the northwest contains moderately well sorted samples with a small zone of moderately sorted samples within it. The zone represents the best sort ing in the area studied. This area also contains a smaller concentration ofmicritized grains (fig 9). Small areas of poorly sorted sediments exist in the northeast and more extensively in the

PAGE 50

Northern Great Bahama Bank Distribution of Mean Grain Size t :ugcrlhau4plu Surfnc:e s ample s f r o m curren t projecl Cor e d nin from currcul projcc l lJ
PAGE 51

Northern Great Bahama Bank Dis trib u t i on of Median G r a i n Size gcrlhan4p t u Surfan sampks from, urrenl prujc
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41 Northern Great Bahama Bank I 2 r," m I I ------- -;----- I I 4 msl I I I Bimini I s lands I I i I I I I I I i lmws I ' Sorti 11 g than 4 pho S urftu.c fru m t urn: ul prnjcl'l Core da1: 1 frn m o.:urrenl project Uata from Hoss. 1994 ..... / /: ps (_:__-. ........ : ms I I I I I I I I EXI'I.ANA TION p s = poorl y surtcc.l m s = moc.Jeralel y sortcc.J 111\\'S = modcralcl y 1\'l'l l strtc
PAGE 53

42 south. A region of moderately well sorted material extends to the southwest from Andros Island, surrounded by moderately sorted sediments. Skewness measures the lack of symmetry of the grain size distribution within a sediment sample. Figure 19 shows three areas of concentrated skewness values. A large region in the south central portion of the study area contains samples with skewness values < -1. In other words there is an elevated concentration of coarse material within the sample. Two smaller areas contain positively skewed samples, which means they have a secondary population of finer material. Surface Sediment Facies All textural and compositional data were analyzed in terms of their characteristics and distributions in order to designate different sediment facies. Table 3 is a summary of the facies defined from the surface sediment samples. Each facies is described in detail below, followed by a description of their geographic distributions relative to one another The pellet facies is characterized by a large percentage of pellets ( > 40%) and the relative lack of mud in the sample (<20%). Mean grain size within this facies ranges from medium to fine sand, while median grain size is typically medium sand. There is a variable amount of true ooids and a relatively higher degree of surficial ooids within the samples. The pellet facies exhibits the highest values of sorting within the study area and is moderately to moderately-well sorted Other grain types are found within the pellet facies, but constitute less than 20% of any given sample and usually less than 10 %

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Northern Great Bahama Bank Skewness S urface smples f ro m c urrcnl p rojec t C o re data fr o m curre nt proj ec t .l Data f rom B oss 1994 I I I I I I I I 43 I I I ------------&--r----& I -----------------------------{--------------------B i mini I s land s I i I I ; I I I i f' I I I I i ,.... . ,. .. . .. J I I I I . 1 ... 1 I I I I lfX'Jint J t lrJh ---------;-------o--J o ult c r s Cay b 0 0 0 0 20 c:::. c:::a Nautkal i\ til. s 0 41l i c:::& c=-r=w r==w 25' 1Xl I I I I I 0 1 I I I I I I i I i I I I I I I i 7X''Xl I I Kiltum lc.a s N i Figure 19 Contour map showing the distribution of skewness values within the study area.

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FACIES MAJOR COMPONENTS TEXTURAL CHARACTERISTICS (sand & gravel) MISCELLANEOUS CONSTITUENTS Pellet <20%mud mean grain size=me dium to fine sand variable amounts of true ooids > 40% Pellets moderately to modera tely well sorted superficial ooids common <20% of any other component Pellet!Grapestone <5%mud mean grain size=medium to coarse sa nd > 20% Grapestone moderately to moderately well sorted variab l e amounts of any other component > 20% Pellets Pellet/ Halimeda <20%mud mean grain size=medium to fine sand >20% Halimeda moderately to poorly sorted variable amounts of any other component > 20% Pellets Pellet!Micritized Grain < 20% mud mean grain size=medium to fine sand > 20% micritized grains moderately to moderately well sorted va riable amounts of any other component > 20 % pellets Halimeda <5%mud mean grain size=medium to coarse sand > 25% Halimeda moderately to poorly sorte d variable amounts o f any other component < 20% pellets Pellet Mud > 20 % mud m ean g r ain size=fine sand variable amounts of any other component > 40 % pellets m oderately to poor l y sorted Mud > 50% mud mean grain size=fine sand abundant pellets and micritized grains poorly sorted variable amounts of any other component Hardground in situ rock NIA each characterized indiv i dually Tab l e 3. Summary of criteria for the disignatio n of facies on the northern Great Bahama Bank.

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45 A near absence of mud (<5%), along with the abundance of pellets (>20%) and grapestone grains (>20%) typify the pellet/grapestone facies. As one might expect, mean grain size is large and ranges from medium to coarse sand. Because grapestone formation requires currents strong enough to transport fine silt and clay-sized material but insufficient to move sand and coarse silt (Gebelein, 1974), moderate to moderately well sorting is not surprising. Variable amounts of other grain types occur within the pellet/grapestone facies, none of which contribute greater than 20%. Halimeda and pellet grains are most common within this facies, each constituting greater than 20% of the sample. Mud content is less than 20% Mean grain size is fine to medium sand. Sorting is moderate to moderately-poor, most likely resulting from larger Halimeda plates within the samples. No other grain type contributes highly to the sample, although many are present. An abundance of pellets and micritized grains of unknown origin (>20% each) characterize this facies, and mud content is <20% Mean grain size is medium to fine sand. Other grain types are present, but are less than 20% each. The Halimeda facies is very much like the pellet/ Halimeda facies, but lacks the abundance of pellets (<20%) and mud (<5%). Further, Halimeda fragments constitute more than 25% of the sample Mean grain size is medium to coarse sand, and sediment is moderately to poorly sorted Coarse mean grain size and poor sorting is likely due to large Halimeda plates in the sample. Variable amounts of other grain components are present within this facies, but contribute less than 20%.

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The pellet mud facies contains > 40% pellets and between 20% and 50% mud Mean grain size of the sand and gravel fraction is fine sand. Moderate to moderately poor sorting is a result of gastropods within the sample, and a minor amount of lithified sediment fragments. Variable amounts of other grain constituents are included but contribute less than 1 0% 46 Samples from within this facies have mud contents greater than 50%. Mean grain size is fine sand, and samples are poorly sorted. Many cerithid gastropods are found in the samples, resulting in the observed sorting trend. The most common sand sized grain components are pellets and micritized grains of unknown origin, although other types are present. Distribution of Facies The distribution of sediment facies defined above are shown in figure 20. The west central portion of the study area is dominated by the pellet facies. One small area, south ofBimini, is characterized by the pellet!Halimeda facies. Sediments of the pellet/grapestone facies trend northwest/southeast across the northern 1 / 3 of the study area. Some small areas of the pellet!Halimeda facies are scattered within the pellet/grapestone facies. The northeast corner of the study area is covered by sediments of the Halimeda facies, which is separated from the pellet/grapestone facies by a zone of the pellet! Halimeda facies.

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Northern Great Bahama Bank 7'fiXI Surface Sediment Facie s S u rface sampl es from c u r r c n l projccl Core dnl a from c u rrcnl projct' l Daw f ro m Boss. 1994 EXPLANATION HJ Pellei/Grapcslo n c Pcllcil/1a/imeda 0 Pelle! E!llalimetla EJ Pelle Mud [J Mud Pdlci/ Micrilizcd Grain I I I I I I I I 1 -------------! c::MI c::::M K ilolll('tC'rs N Figure 20. Surface sediment facies distribution for the northern Gre at Bahama Bank. 47 : w

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48 The mud facies is located in the middle of the southern half of the field area (fig. 20). This area is surrounded by sediments of the pellet mud facies Except for a zone of the pellet/Halimeda facies in the southwest and a few small areas of the pellet and pellet mud facies (fig. 20), the remainder of the field area is covered by the pellet/micritized grain facies.

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HOLOCENE STRATIGRAPHY Core Sediment Facies All core sediment facies are the same as described earlier for surface sediments In addition to the sediment facies, however, lithified aggregates of sediment and hardgrounds are present and are locally common downcore Each of these will be discussed in detail below Lithified Sediments Aggregates of lithified sediment are common in many of the sediment samples taken from the cores These fragments range in size from medium sand to pebbles and are composed of the same grain types as their surrounding sediments No traceable surfaces are identified from the cores, leading one to believe that the zones of cementation are very localized Horizons where many large pieces were found are identified on the core logs in Appendix 1 49 Petrographic examination of lithified sediment fragments reveals a very fine grained intragranular fibrous marine cement (fig. 21A) probably aragonite (Scholle 1978). Presence of this cement is the means by which the grains were classified as lithic fragments as opposed to grapestones. Cementation of this sort is commonly seen in

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Figure 21. Photograph showing A) fibrous marine cement in a lithified sediment fragment, and B) freshwater, blocky spar cements and neomorphism in a hardground sample. 50

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51 modem carbonates, and occurs most effectively where normal deposition has either been interrupted or is extremely low (Williams et al., 1982) In addition to lithic fragments, it was noted that many individual grains, especially in the western portion of the study area, have a thin rind of fine-grained cement around them Due to the fine and fibrous nature of the cement and its variable distribution cementation most likely occurred quickly (Williams et al., 1982) and in localized areas. Subsequent mobility of the bottom sediments, possibly during storms, may disaggregate the fragments This could explain why more large fragments are commonly found in cores from the middle and eastern portions of the bank where the bottom is relatively stable as opposed to the western margin area, where agitation ofbottom sediments is common Hardgrounds Bahamian hardgrounds, as used in this report are lithified surfaces formed as the result of subaerial exposure During the last interglacial, when sea levels were 1 O's of meters lower than present sea level (Boardman et al., 1989), extensive hardgrounds were formed on the subaerially exposed carbonate surface This surface is a very good reflector for high resolution seismic studies as noted by Boss (1994) for the northern Great Bahama Bank. As documented by several authors (e.g. Enos, 1974; Boss, 1994) the Pleistocene surface is very irregular Probe data and vibracore data from this study substantiate this characteristic (fig 22). In all cores taken throughout the study area it was expected that penetration would reach a hardground. Unfortunately this was not always the case, as shelly layers or lithified sediment layers often hindered penetration.

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2(,''00 -1-t .................... ... 1_._._._. Bimini I s lands Northern Great Bahama Bank l 7 15m l 43tm 8.41m I --t-f l l 7 1'7111 l 7 9 1 m 5 60m Depth to Hardground Core l ocations from c urr en t pro ject l Core location s I ro m Bo ss. 1994 l 6 .tom l 7 22m l c,.'JHm 4 65m 5 20m 3 .09m W illiams I sland l J o uh ers Cay 4 31m & .:'Om 0 3 64 f I t + ?X' lXI I 52 0 20 c:::=-c=-0 N II u tl< nl Mil.s 40 r=w r==w c:::::M elM Kllom r tr rs Figure 22 Map showing locations of cores and depth of hardground surfaces below the water surface as obtained from core and probe data

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53 Several cores did penetrate to a hardground, however, and samples were taken and analyzed petrographically as well as for radiocarbon dating. Petrographically, all hardgrounds classify as oopelsparites on Folk's (1962) classification scheme, or pellet rich grainstones according to Dunham (1962). Various amounts of other grains such as Halimeda fragments, bivalves, gastropods, and corals are present throughout the samples Freshwater, blocky spar cements are pervasive in all samples, and recrystallization of primary carbonate is widespread (fig 21B). In some cases, several generations of cementation are identifiable. For descriptions of individual hardground samples, refer to Appendix 4 Figure 23 shows the core locations from which Pleistocene hardground samples were dated, as well as the dates which correspond to each An age of 21,330 yrs BP was reported from the sample in the north. In contrast, the sample taken from a core near Andros Island had an age of 30,400 yrs BP. The samples taken from two cores in the south, approximately 6 km apart, show a difference in age of over 10,000 yrs. Ages are 28,630 yrs BP and 18,570 yrs BP. One lithified sediment sample from a core in the northeast had an age of 3,530 yrs, demonstrating that these lithic clasts are Holocene. Additionally, X-ray analyses were conducted on a Scintag XDS 2000 X-Ray Diffractometer on three hardground samples in order to determine overall mineralogy Findings indicate that the hardgrounds are primarily calcite, with minor amounts of aragonite.

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2h000 Bimini I s l a nd s Ora nge Cay 0 Northern G r e a t B ahama B ank 50 40 30 20 so 40 7'1,M I I 50 Loca tion s of D a t e d H ardg r ounds Cor e l ocatio n s f r om curre nt p r o ject Cor e l ocatio n s f rom B oss, 1994 40 30 J oullc rs Cay 20 31),40 I + I 330 883 ::!H/l.l()+J -882 882 t K.570 + I 140 7 1\'IMI I 54 t:=iM L::IIIIM N aulical 40 t::llllfM,.....,. co::. r="W K i l o m t l t rs N r Figure 23. Map s h owing loca t ions and rad i ocarbon dates of hardground samples taken from co r es.

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55 Sediment Facies Distribution Through Time In an attempt to describe the Holocene sediment facies distributions through time, seven cross sections were constructed across the study area (fig. 24). The following pages will describe each of these beginning from the northernmost cross section, working south, followed by a description of the sediment facies' three-dimensional distribution. Section A-A' is the shortest of the seven sections (fig. 25), and stretches only 48 km across the banl(. Stratigraphically this sectio n is homogeneou s, and comprised entirely of the pellet facies. Surface sediments along this transect are of the pellet facies as well, with only a thiH veneer of pellet grapestone facies in the easternmost portion. Lithified sediments are found in all three cores but are most abundant in the easternmost core (BB3-2). Section B to B' is composed almost entirely of the pellet facies, with increasing amounts of lithified sediment fragments toward the east (fig. 26). A thin veneer of pellet/grapestone facies covers the eastern half of this transect as well. Core STA-3 is the deepest of the 4 cores which make up this 69 km long section, and has a hardground at its base. In addition, a horizon of muddy laminations exists in two of the cores, which may or may not be correlative. It should be noted, howe ve r that these are the only two cores which exhibit any such laminations Very rapid deposition is one explanation for the preservation of these laminations, for bioturbators would likely destroy these structures if given sufficient time.

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Northern Great Bahama Bank I 21110 0 I I ------.. --.. -.. l--t----. ., l I l I I I I I I I I Slllfa.._c.. ...:unpk' If Jill ( 'ntl' data from t:um:nl prnJl'..:l l PJ"J...l I I I I I I I I ------------------------.. -------------I -r-............ ____ .......... ---..... --------.... G . . . H. I I I I I 0 c:::=-c=a Nu ul h:a l 0 56 20 40 r=w r==w t=M c::::8 Orange Caya () I I I I I I I 1\.ilomtttrs F G Figure 24. Inde x map showing location of cross sections constructed across the study area.

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water depth 5.18 m 8.54 m 7.62 m (m) WEST EAST 0.. A I 1 r I * t I : A' 0.5 1.0 1.5 2.0 ... . 0 0 : ..:-"/ . . ..,../ ........ "// L:L.:,.,;....---0 sTA-1 ... ... .. LJ :._: __:_t__!_ 883-1 883-2 10 Kilometers 0 Pellet Pellet/Grapestone [!] Lithified Sediment A sea-level -.., A' Figure 25. Cross section A-A'. The inset represents the true topography of the sediment surface along the tran sect. Hardgrounds are a lso represented where applicable. Vl -....)

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water depth 5 79 m 5 .18 m 6.10 m 3 96 m (m) WEST EAST 0 1 B 1 1" . . . . . . w . . . . . . . . ;;; ;; ;;; ;;; ;;; B ::: 1.0-t 2 0 0 0 0 0 0 I I I j j : 0 0 0 0 0 0 0 0 0 0 0 0 : : : : : : : : : : : : : : : : : 0 0 0 0 0 0 0 0 0 0 II i ......... ..... Y'L.....-....L._ 0 / --...&._ .. L'i.:. . . . . . /' 883-4 --:._:..:. .:_:..:_ . . BB .. : .... : . . . 11. . ,.--. . . . 3-5 . . . . . . . / -...:. .... : l -.:.: . . . . . . . / ......... ....:.... .... .... :// -". : .;/ 8833 ,H / 0 Pellet Pell e t/Grapes tone Lithified Sediment 0 Hardground Fra gment STA-3 0 Figure 26. Cross section B B seal ev e l 10 B' Kilometers 8--------r-----------Vl 00

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59 Cross section C-C' represents a 70.5 km east-west transect (fig. 27). Most of the surficial sediment cover is of the pellet/micriti zed grain facies, which thicken downcore to the east. The majority of sediments downcore across the transect, however, are ofthe pellet facies with only a relatively thin stringer of the pellet/micritized grain facies being traceable between the two westernmost cores The easternmost portion of this transect is comprised of pellet mud underlain by mud and hardgound. The trend of hardground/mud/pellet mud is seen in other transects as well. Only core GBB-2 in the section contains numerous fragments of lithified sediment. Section D to D' represents six cores covering 72.5 km (fig. 28). In the west, the pellet/ Halimeda facies, with a thin pellet lens interfingers with muds and pellet muds. The more extensive mud facies dominates the western half, whereas pellet muds dominate the stratigraphy in the eastern half. Closer to the surface, another thin lens of the pellet facies overlies pellet muds, which in turn is overlain by a thin layer of the pellet/micritized grain facies Hardground is encountered in two cores, one centrally located, and the other to the east (fig 28). Core BB3-8, loca ted between cores with recovered hardgrounds, contains a piece ofhardground at the bottom of the core. Hardgrounds are more abundant in cores that make up cross section E-E' than any other, and actually lie at the sediment surface in core BB2-6 (fig. 29). It is the southernmost section and represents 53.5 km of sediment cover. The hardground is overlain by mud, as has been seen in other transects as well. Overlying the mud is pellet muds, which extend westward across the bank The westernmost core contains sediments predominantly ofthe pelle t/Halimeda facies, with a lens of pellet mud.

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water depth ( m ) WEST 0 c 2 0 5 33 m 5 .18 m 4 .57 m 4 88 m 2.44 m 1--''= I 0 ...... .... 0 0 ... . . 0 ... .. . .. ... ..... . .. . ET ............... I ... 0 0 0 0 -- 0 0 i:i:il:t:i: l =lill ll:l . . __ :..:.. . . . . . rr -:... LL ... --GBB 3 --... -...:..:...: ... _:. ..:-----.4 :.._: ........ ---uBB-1 L:.....:. GBB2 GBB-5 GBB-4 D Pellet Pellet/Micritized Grain IT] Pellet Mud IZI Mud H a rdground [!] Lithified S e diment 0 I Kilometers Figure 27. Cross section C-C' 10 s ea level c c I I 1----::J I EAST C' 0\ 0

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water depth 6.7 1 m 6.71 m 6 .71 m 5.18 m 3.35 m 2.74m (m) WEST 0 1.5 2.0 D 1=+= :T:,., ," ," ," ," ," ," ," ," ," ," ," ," ,", ,", ," ,:T:T:T:T:T:T:T:r:T:T:T r:T: :T:T:T:T:: : lil iii :ll!lll!l:lll!llillilllil iiii1\I\'Iiilill BB2-I D [] E3 Pellet/ Halimeda Pellet Pellet!Micritized Grain Pellet Mud Mud Hardground GJ Hardground Fragment Figure 28. Cross section D D'. BB3-8 0 10 seal evel Kil ometers _____ .... o EAST D' 0\ -

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water depth 6.10m 6.35 m 4.60m 3.90m 3.04 m (m) WEST E . EAST 0 1.5 2.0 I I ........ ... J . J ..... t ..... ltKKt E' Pell e t!Halim e d a [J Pell e t Mud Hardground EJ Lithified Sediment 0 10 l Alii I di M Kilometers Figure 29 Cross section E-E' BB2-4 sea -l e vel E' E 0\ N

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63 Dominated by the pellet facies throughout its length, section F-F' deviates very little from the overlying surface sediment facies (fig. 30). The only difference stratigraphically is a lens of the pellet/micritized grain facies which is not traceable between cores To the south, the mud facies overlies the pellet mud facies which extends to the surface further south Only one core penetrated to a hardground surface (STA-2), which is at less than 1 m depth below the sediment surface. Two fragments of hardground were taken from the same core. In addition, a hardground fragment was taken from BB3-5. Lithified sediment fragments are found in BB3-1 and BB3-6, both in the northern half of the study area (fig. 30) As is the case for all sediments to the north, the pellet facies dominates. Section G-G' shows a local, thin veneer of sediment of the pellet/grapestone facies in the north (fig 31) Surface sediments are patchy toward the south ofthis section, including mud, pellet mud, and pellet/micritized grain facies. Stratigraphically, many facies interfinger in the central portions of the section. However, pellet mud dominates in the south A lens of the pellet/micritized grain facies underlies pellet muds and pellet facies in core ST A-20 In addition, the southernmost core is bottomed out b y mud and a hardground Lithified sediment fragments are found in the two northernmost cores, while hardground fragments exist in the two southernmost cores. The easternmost cross section, H-H is about 73 Ian i n length. Sediments ofthe pellet facies dominate in the northern portion of the section, capped only by a thin veneer of the pellet/grapestone facies on top. Many lithified sediment fragments are found in the core (fig 32) The middle of the section is composed of pellet muds, underlain by mud

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water depth 8.54 m 5.79 m 5.79m 7.32m 5.33 m 6.71 m 6.35 m SOlJfH ( l NORTH ..........._,,,,,,,,,'I 1,,,, ;;:;;>!::::1 :1 m I l I 1 0 F I I I I I I 0 5 1.0 1.5 883 2 0 -Q Pell et Pellel/Mi critized Grain [J P ellet Mud E::J Mud Hardground Lithified Sediment 0 H ardground Fragment .. '" .:..!1 883---..:. 0 1 0 Kilometers Figure 30. Cross sect ion F-F'. 883 ..... ---. .. -----__ :--: _____ __ 088 sea-level 0\

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water depth 7.62 m (m) NORTH 0 G 1. 1.0 1.5 2.0 :.1: BB3-2 0 Pellet E:3 PelleVMicritized G r ain [J PelletMud H a r dgrou nd !!] Lithifi e d Sediment G Hard gro und F r agme nt 6 1 0 m .:_ :-.:. ...:_ .:_: . BB3-4 ----0 10 Kilometers Figure 31. Cross sect i on G-G'. 4 57 m 4 .66 m 5.15 m GBB-3 STA-20 5.18 m BB 3 -8 3 .90 m SOUTH G' 0\ Vl

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water depth 3.96 m 2.44m 2.74m (m) NORTH 0 H 0.5 1.0 1.5 2.0 .... : :-r: :. : ..... . . . . . . }[ .. : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ... : ................... ... . . . : .. 1-:.:.:.L:.L:J.:.L:.L:.L:.L:.L: .:.L:. ..... : :. :. :. : :. :. :. : : 0:.:.: . :. .. .. .. : ... : : .. :! .. ... .... .. ..... ,,,,,,,,,, / ./ / / / / / / / / / / / / / / 4f1 . . . . / ;';',.',.' '.,' ';';';';';'.,',.';';',.',.',.',.'' 0 0 /,. /'/';';';';';';';' ',.' ';'/';';';';';';' '... :;...oo-':-o----......... ..:._--.:.....:_ ,.';';';',';';';';';',';';',',' ';' ',';';';''' 883-3 ''''' '''' '' ',' '' 0 Pellet B Pellet/Grape sto ne BJ P elletMud !{_] Mud ----GBB-1 0 10 Kilometers sea-level Pellet/M i c r it i zed Grain Hardground Lithified Sed iment 0 Hardground Fragment H H' Figure 32. Cross sect ion H-H' SOUTH H' 0\ 0\

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67 and hardground The mud pinches out toward the south, but pellet mud persists and dominates, with only a thin layer of the pellet/micritized facies at the top of the core. A hardground is encountered in the southern core as well. The three-dimensional distribution of sediments and sediment bodies is quite simple in the northern portions of the study area and gets more complex to the south. The pellet facies dominates all northern cores to depths exceeding 2 m in some cases The only variation in the north is the thin (0.2-0.3 m) cover of the pellet/grapestone facies. The distribution of the pellet/micritized grain facies changes toward the middle of the study area A thin pellet/micritized grain zone in the west thickens to over lm in the east, where it interfingers with pellet mud which is common in the stratigraphy to the south and southeast. Many different facies exist in the lower third of the study area. These include 1.0-1.5 m thick deposits of the pellet/Halimeda facies in the southwest corner which do not extend very far east on the surface or stratigraphically Although not reflected in the surface sediment distribution mud and pellet mud are extensive in the south and both thicken to the east. Only a very thin cover of the pellet/micritized grain facies exists over the mud and pellet mud

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68 DISCUSSION Potential Contribution of Mud by Whitings Whitings are distinct patches of suspended lime mud among relatively clear waters found in many shallow carbonate platforms, banks and seas Several hypotheses have been proposed about the origin of whitings, including a fish mud theory (Boss and Neumann, 1993), direct precipitation in seawater (Broecker and Takahashi, 1966; Morse et al., 1984), biologically induced precipitation (Robbins and Blackwelder 1990; 1992) and as a turbulent-flow phenomenon (Boss and Neumann, 1993). Whatever the origin, it has been suggested that whitings are the major source of lime mud on Great Bahama Bank (Tao, 1994) Holocene deposits of up to 2m of the mud and the pellet mud facies raise questions concerning accumulation rates and the production of mud across the Great Bahama Bank. From cross sections and samples taken from individual cores, accumulation rates have been calculated at specific locations, as well as over large areas of the bank. In addition, the plausibility of mud production by whitings as a substantial sediment source will be examined and compared to results from Robbins and Yates (1992) and Yates (1996).

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69 Neumann and Land (1975) suggested 5,500 years BP as the beginning of Holocene sediment deposition in Bermuda and the Bahamas. Recent investigation of Holocene sea level in the Bahamas derived from C-14 dates of peat samples from San Salvador, Andros Island, and the Bight of Abaco (Boardman et al., 1989) indicate that deposition began closer to 6,000 years BP, when sea level was about 5 meters lower than present. These are the parameters used in this study. The calculation of mud accumulation rates in individual cores throughout the study area yields varying results. Weighted averages of mud throughout the cores were compared to total core lengths to determine accumulation rates. Because not all cores reached a hardground surface, accumulation rates reported here are minimum rates. Overall, eight cores were examined from cross sections B, C, and D (figs. 26, 27, and 28). Results of the calculations are summarized in Table 4 X-ray diffraction analysis of samples indicate that the mud contained within pellets is aragonite, the same mineralogy as the unconsolidated mud within samples. Therefore, pelleted mud and unconsolidated mud are assumed to be from the same source. If the amount of mud contained in pellets is also accounted for in calculations of mud accumulation, the rates are greater (Table 4). Accumulation rates were also calculated for two defmed bodies of sediment within the study area. Because cross sections were constructed along several transects, they were used as boundaries. The areas were chosen by superimposing a whiting distribution map from Tao (1994) over the surface sediment facies map produced from

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this study Boundaries were chosen to include the areas of the highest occurrences of whitings. Core# Cross mud accum. rate, mud accum. rate, Section excluding pellets ( cm/1 03 yrs) including pellets ( cm/1 03 yrs) BB3-3 B 0 8 8.1 STA-3 B 2 5 24.1 GBB-3 c 2 0 16.9 GBB-1 c 12 5 17.6 BB3-7 D 4 5 8 8 BB3-8 D 9.0 18.4 BB3-9 D 9.3 24.0 BB3-10 D 9.8 11.2 Table 4. Summary of mud accumulation rates from individual cores, including and excluding mud contained in pellets The first area is contained between cross sections B-B', D-D', F-F', and H-H' 70 (fig. 24). Using thicknesses of recovered cores along transects, and assuming a horizontal sediment surface, the calculated volume of sediment contained in the 4.83 x 109 km2 area is 9.69 km3 Weighted averages of79 core samples from within the region reveal mud content to be 25% by volume, not including pelleted mud, while sand and gravel content is 75% by volume. Mud, therefore, is accumulating at a rate of96.9 g/m2/yr, or 8.4cm/103 yrs. The rate of total sediment accumulation for the area, including pellets, is 34 cm/103 yrs. Similar calculations were completed over a smaller area of2.98 x 109 km2 and volume of5.25 km3 The area is bounded by cross sections C-C', D-D', F-F', and H-H' (fig 24), and represents the region where most, but not all whitings occur. Results

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71 i ndicate that mud content is 32% by volume and sand and gravel content is 68% by volume. Calculated accumulation rates are 108 8 g/m2/yr, or 9.5 cm/103 yrs for mud. The rate of total accumulation is 30 cm/1 03 yrs Comparisons of total accumulation rates calculated for the two areas defined in this study are comparable to the rate calculated by Boss (1994) for the northernmost portion of the Great Bahama Bank. Boss reported rates between 0 and 1 5 m/103 yrs, with a median rate of 46 cm/1 03 yrs. Values reported here are well within this range In addition, there are several factors which justify the lower accumulation rates relative to those reported by Boss (1994) First, most of the cores utilized in these calculations did not reach a bedrock surface, thus causing the reported values to be minimum accumulation rates Further, thicknesses of accumulated sediment in the south, are less than those reported by Boss (1994) in the north. Lastly, it is worth mentioning that Boss used a slightly different porosity of 50% as compared to the overall porosity of 44% used in this study. The difference in porosity decreases Boss' accumulation rate of 46 cm/1 03 yrs to 41 cm/1 03 yrs, which is even closer to values reported in this study. Calculated accumulation rates of mud in areas where whitings are common, along with the results of experimental work on production rates of carbonate by green algae and cyanobacteria in whitings (Yates, 1996), allow speculation on the role of whitings in mud accumulation on the Great Bahama Bank As stated previously, accumulation rates of g! 2 2 mud over the larger and smaller areas defined are 96.9 m /yr and 108.8 g/m /yr, respectively Recent laboratory experiments yield mud production rates of 4,960 kg/day for an average sized bloom of 0.64 km2 and 5m depth by the green algae N. atomus,

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72 (Yates, 1996) Although whitings have been documented year round, they occur at a greater frequency during the spring and winter (Tao, 1994) If it is assumed that a whiting of the size indicated above is present daily for a six-month period and that no whitings occur during the remainder of the year the amount of sediment produced would be 1,414.4 g/m2/yr. These numbers indicate extremely high production with very little accumulation over the period of 1 year, assuming that all mud is produced by whitings. One further set of calculations was made in order to determine the settling rate of particles to ascertain the possible dispersal of mud by currents Assuming a particle diameter of2 microns, Stoke's law yields a settling rate of386.5 hours or 16.1 days in a 5 m colurrm of water. l'he effect of small diurnal tidal currents and wind driven currents would be to transport this material westward across the bank, and eventually off the bank, as indicated by the leeward drift of whitings and the Holocene progradation of the western margin (Wilbur et al., 1990) However, Smith (1940) concluded that water bodies have a residence time on the bank of up to 1 month, thus allowing for deposition of at least a small portion of whiting-produced carbonate before transport offthe bank. Comparing production rates from Yates ( 1996) to mud accumulation rates calculated in this study, a maximum of8% ofthe carbonate produced by whitings is preserved in the Holocene stratigraphy as mud. Agreement between accumulation rates calculated at individual locations on the bank and for large areas ofthe bank is very good. Rates of8.4 cm/103 yrs for the large area and 9 5 cm/103 yrs for the smaller area are within the range of rates calculated from specific locations on the bank of0. 8 cm/103 yrs to 12.5 cm/103 yrs as well as those

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reported by Boss (1994). Although it is obvious that rates of mud accumulation differ from one place to another, large scale trends across the area are useful in assessing the maximum preservation potential of whiting-produced mud. Texture and Composition 73 Granulometric properties such as grain size and sorting are commonly used by scientists studying siliciclastic deposits to indicate energy levels within depositional environments. These properties are much less significant in carbonate sedimentology as a result of the many mechanisms for production and breakdown of carbonate grains, however they can still be useful if analyzed carefully (Tucker & Wright, 1990). For interpretation of carbonate sediment textures as indicators of energy levels within environments on the Great Bahama Bank, it will be assumed that the sediment surface is in equilibrium with the hydrodynamic properties in that area. A known exception to this, however, occurs within the mud and to a lesser degree, the p e llet mud facies, where subtidal microbial mats stabilize the sediment enabling it to withstand greater current velocities than it would without the microbial cover (Bathurst, 19 75). The examination of textural characteristics for th e northern portion of the study area lend support to findings b y Boss (1994) concerning the westward transport of sediment. Values of sorting indicate that sediments in the northeast are somewhat more poorly sorted than those in the northwe s t (fig. 18). Examination of individual samples reveals that the poorer sorting of northeastern platform sediments results lar ge ly from a

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74 slightly greater (<2%) proportion of mud and fme sand relative to sediments in the northwest. Both the finest and coarsest components are missing from sediments in the northwest, as indicated by its moderately well-sorted nature. Boss (1994) related similar findings to winnowing of fine-grained components, and differential sediment transport capable of moving only those sediments of medium to fine sand size. The greater abundance of mud and fine sand in the northwest is interpreted to represent an area of local sediment production which contributes particles across the entire grain-size spectrum (Newell et al., 1959; Boss, 1994). Boss (1994) believes that sediment production rates are sufficient enough in the northeast to mask the effects of physical reworking, whereas those in the northwest do not. Constituent composition ofbank-top sediments may provide additional evidence for transport across the bank Skeletal grains are more commonly found in sediments in the northeast than are in the northwest (fig 12) The greater abundance may be due to the higher sediment production in the northeast. As a result of increased production along with westward transport, it may be expected that sediments in the northwest would have a higher concentration of skeletal grains. In contrast, it is believed that many non-skeletal components are derived from skeletal grains which have been micritized during transport across the bank (Bathurst, 1975). Because micritization and transport are both time dependent, a progressive sequence of micritization might be expected in the direction of transport (Boss, 1994). Unfortunately, degrees of micritization were not accounted for in this study, and thus cannot be used as an indication of westward transport. Although the interpretation of transport directions from textural and compositional trends is a useful

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75 tool, some knowledge of existing conditions is necessary to avoid misinterpretation For example, westward transport across the northern Great Bahama Bank has been previously documented by several authors (Smith, 1940; Hine and Neumann, 1977; Hine, 1983) thus providing a basis for correlation between sedimentological characteristics and transport. Because tidal currents in the southern portion of the study area are very low (Smith 1940), and the currents are generated mainly by winds, interpretation of the textural and compositional characteristics is simple Mud content is highest in the southern region (fig. 14) The presence of microbial mats and the cohesiveness of mud prevents suspension and transport by the low-energy currents. Sorting values are poor in the south/central portion of the field area, and increase to moderately-well sorted to the east (fig 18). Sorting trends are partially due to the relative abundance (>2%) of gastropod shells, which are reflected in the gravel concentration (fig. 15) In addition local production of grains of all sizes (although mud and fine sand is most common) and the fact that currents are unable to transport even the finest material in this region after deposition results in the observed trend Mean grain size is fine sand in the south/central region, and increases to medium sand in the east (fig 16). The distribution ofmicritized grains is highest in the south/southwest (fig. 9), and is probably the result of extremely long residence times of grains in this area, together with abundant activity of boring algae One set of textural trends seen in the study area is very different from those in their immediate vicinity An area extends 10's ofkm west and southwest of Andros

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76 Island which contains moderately well sorted sands (fig. 18), mud concentrations between 5 and 20% (fig. 14), and a mean grain size of medium sand (fig. 16). All textures indicate that current velocities in this area are stronger relative to the surrounding areas, preventing microbial mat formation and winnowing fine-grained material. A core taken near this area shows a hardground less than 4 meters below the water surface, and about 1 m below the sediment water interface (fig 32) which may be dynamically i ft affecting water movements in this localized area Facies Distributions A main objective of this study was to produce an updated surface sediment facies map for the northern Great Bahama Bank (fig. 20). Although similar in many ways to previously published and widely referenced maps (figs. 3 and 4) by Purdy (1963b) and Enos (1974), several differences can be noted The most obvious difference with respect to Purdy 's map is the extent of the mud facies Purdy defined a large elliptical area west of Andros Island (fig. 3). Results from this study show a much smaller zone of surface sediments with a high concentration of mud (>50%). This is due to a difference in criteria set up for the mud facies distinction The main difference between Purdy's mud facies and his other facies is the high content of particles smaller that 0.125 mm (Purdy, 1963b ) In other words, he included very fine sand in reported percentages. Purdy (1963b) reported a range of29.7% to 92.3% ofmaterialless than 0 125 mm for samples making up his mud facies. The mud

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77 facies defined in this study is characterized by 50% or greater of particles less than 0.625 mm. Purdy's mud facies distinction is misleading because of the inclusion of very fine sand. The pellet mud facies as mapped in this study is less extensive than that of Purdy (1963b) Much of the pellet!micritized grain facies falls within his pellet mud facies (fig. 20) This is the result of the ident i fication and inclusion ofmicritized grains in the map from this study, whereas there is no mention of such grains by Purdy (1963b) Another difference between Purdy's map and the one produced in this study is the Halimeda and pellet! Halim e da facies Purdy did not identify the concentration of Halimeda grains in thin section for either ofthe two areas that were mapped in this study (fig. 20). The inclusion of Halimeda is very important in mapping true representations of the sediment types present. Observations by divers during core retrieval indicate that areas defined by the Halimeda and pellet! Halimeda facies' contain large amounts ofliving Halimeda, thus confirming that these are zones of high production of Halimeda on the bank The other two widely distributed facies defined in this study pellet and pellet!grapestone, mimic findings by Purdy for the oolitic and grapestone facies (figs. 4 and 20). Boundaries for the grapestone facies of Purdy and the pellet!grapestone facies of this study are fairly close to one another, although not exact. This is expected if one considers that surface sediments especially those which require agitation and currents to form, will change location slightly over time In addition sampling density and overall numbers in this study are greater than that of Purdy's (1963b) for the northern half of the Great Bahama Bank.

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78 Correlation can be made between Purdy's oolitic facies and the pellet facies defmed in this study. The pellet facies is coincident with areas defined by Newell et al. (1960) where optimum conditions exist for oolite formation. As stated previously, superficial ooids, and to a lesser degree true ooids, are found within the pellet facies The fact that superficial ooids were classified as the original grain type in this study led to the difference in facies designation. There are several small variations in sediment facies distribution between Purdy's map and the map produced in this study (figs. 3 and 20). It is important to note that these small variations are defined by only one or two samples. Local variability of sediment type is fairly common, likely due to the interaction of currents and the irregular Pleistocene surface which underlies the Holocene sediment suite, which extends close to the surface in many areas (Enos, 1974; Boss, 1994) Enos' surface sediment map (1974) is based on depositional textures of sediments combined with grain type (fig. 4) Unfortunately, the only grain types taken into consideration for mapping were oolite, pelletoid grains, and skeletal grains. The result of this is a very different surface sediment facies map than the one produced in present study First, as was the case when compared to Purdy's map, the mud facies defined in the present study is much less extensive than Enos (1974) corresponding pelletoidal wackestone Data for this portion of Enos' map were taken from Purdy's (1963b) study, therefore the location and extent is the same as was described above.

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79 Only three other surface sediment categories can be compared between Enos' ( 197 4) map and the one produced from this study Enos mapped a hard pelletoidal grainstone, a mixed oolitic / pelletoidal grainstone and a pelletoidal packstone (fig 4). The hard pelletoidal grainstone distribution is similar to the d i stribution of this stud y 's pellet/grapestone facies Enos (1974) does not include grapestones in his classification because it overlaps the other grain categories used Although grapestones are composed of ooids, pellets and skeletal grains their depositional environment and factors responsible for formation are different than that for the individual grain types Therefore, they should be mapped separately The mixed oolitic-pelletoidal grainstone distribution of Enos (1974) is very similar to the distribution of the pellet facies defined in this study The pelletoidal packstone distribution however, is very different. The pellet mud, pellet/ Halimeda, and pellet/micritized grain facies of this study are all coincident with Enos' pelletoidal packstone distribution (figs 4 and 20) Holocene Stratigraphy In trying to rationalize the stratigraphic nature of the Holocene sediment cover with respect to time it is important to first understand the nature of the underlying Holocene/Pleistocene unconformity. The unconformity was mapped in the northern portion of the study area using high-resolution seismic reflection (Boss 1994). Relief on the Pleistocene surface in the north is described as being primarily of arcuate eolianites

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80 near platform margins, with several broad (8-20 Ion wide}, low relief topographic highs which are separated by linear troughs coincident with geologic structures apparently dating from the early history of the platform (Boss, 1994). Although detailed seismic data do not exist for most of the present study area, it will be assumed that as a result of the role of tectonics in the early history of the bank, along with historical effects such karstification on the Pleistocene surface, localized relief is common (Dietz et al., 1970; Uchupi et al., 1971; Ladd & Sheridan, 1987; Sheridan et al., 1988; Eberli & Ginsburg, 1989). Investigation of water depths over core locations, thicknesses of recovered material, and the distribution of hardground surfaces recovered from cores indicate that relief on the Pleistocene surface is higher in the eastern portion of the study area than in the west (fig. 22). It is important to note general trends in relief when trying to explain the distribution of sediment packages on the Great Bahama Bank through time. It has been shown that the pellet facies dominates the stratigraphy in the northern half of the study area. Seismic data from Boss (1994) indicates a westward thickening of Holocene sediments in the north, due to the westward transport and subsequent pile up of sediment. As discussed previously, winnowing by westward moving currents results in the lack of mud in the northwest. The formation of grapestones in the northern region must be a relatively recent phenomenon as evidenced by only a thin surface cover, and its lack of abundance in underlying deposits. Cross section C-C' shows differing sediment types within the stratigraphy (fig 27) This section is made up of cores which are aligned with the west of the tip of Andros

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81 (fig. 24). The sediment which presumably covers the Pleistocene surface in this region is of the pellet facies Sheltering from wind driven currents from the east by Andros Island may have allowed for increased residence times and subsequent degradation of grains which make up the extensive pellet/micritized grain facies in this environment. The easternmost core (GBB-1) in section C-C' (fig 27) exhibits what is interpreted to be tidal deposits in the lee of Andros Island Extensive tidal deposits are present today west of Andros Island (Scholle 1983). In light of the general increase in elevation of the Pleistocene surface toward Andros, it is likely that tidal deposits began to accumulate at the onset of sea-level rise in this area of the bank. Stratigraphically this is documented by very muddy deposits in areas adjacent to Andros Island (figs 27, 28, 29, 31, 32) The westward extent of muddy deposits is substantial, as can be seen from the surface sediment map produced in this project (fig. 20), as well as in stratigraphic cross sections in the southern portion of the field area (figs 27-32) Reasons governing the extent of muddy deposits to the southwest include the sheltering effect from wind driven currents by Andros Island, low tidal current influence the microbial mat formation described earlier which prevents erosion of muddy deposits and possible accumulation from whitings Accumulations of the pellet/ Halimeda facies in the southeast are worth mentioning in that these areas of high productivity have been persistent over the past 6 000 years In addition, mud and pellet mud deposits in the southern portions of the study area have been constantly accumulating since the onset of carbonate production in the Holocene (figs 28, 29) Because no detailed studies on the Holocene stratigraphy

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have been conducted, results of this study are very important in understanding the Holocene sediment deposits. Further research is needed, however, if the details of Holocene stratigraphy and facies architecture are to be explained. 82

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CONCLUSIONS Examination of textural and compositional trends, the distribution of facies through time, and calculated rates of sediment accumulation allow the following conclusions to be drawn about Holocene sediments and stratigraphy of the northern portion of the Great Bahama Banlc 83 1 Seven surface sediment facies are present on the northern Great Bahama Bank. These include a pellet/grapestone facies pellet/ Halimeda facies pellet/micriti z ed grain facies pellet facies, Halimeda facies, pellet mud facies, and mud facies Core sed i ment facies are the same as those described for surface sediments. 2. Textural and compositional data from surface sediments support evidence for westward cross-platform transport in the northern portion of the study area, although more information on hydrodynamic conditions is necessary for accurate interpretations 3 The pellet facies dominates the stratigraphy in the northern half of the study area The widespread pellet/micritized grain facies in the northern Andros Island area is due to sheltering from wind driven currents by Andros and long residence times of sediment in this region Reasons governing the amount and distribution of the mud and the pellet mud facies in the south are sheltering from currents by Andros Island low tidal current influence, microbial mat formation and some accumulation from whitings.

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Further research is needed, however, if the details ofHolocene stratigraphy and facies architecture are to be explained 84 3. Calculated sediment accumulation rates of8.4 cm/103 yrs and 9.5 cm/103 yrs for two large areas on the bank are within the range of values calculated from individual cores of0.8 cm/103 yrs to 12 5 cm/103 yrs Values increase when mud contained in pellets is accounted for, and range from 8 1 cm/1 03 yrs to 24 1 cm/1 03 yrs. In addition, total sediment accumulation rates of 30 cm/1 03 yrs and 34 cm/1 03 yrs from this study are within the range calculated by Boss (1994) in the northernmost Great Bahama Bank. 4 Accumulation rates of mud within the study area, when compared to whiting production rates from Yates (1996) indicate that a maximum of 8% of the carbonate produced by whitings is preserved in the Holocene stratigraphy.

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REFERENCES Adams, A.F ., Mackenzie, W S. and Guilford, C., 1984, Atlas of Sedimentary Rocks Under the Microscope Longman Group, Ltd ., Hong Kong, 104 p Ball, M.M ., 1967, Carbonate Sands ofFlorida and the Bahamas, Jour. Sed. Petrology, v. 37(2), pp 556-591. Ball, M.M., Shinn, E.A., and Stockman, K W 1967, The Geologic Effects of Hurricane Donna in South Florida, Journal of Geology, v. 75, pp. 583-597. Bathurst, R.G.C., 1975, Carbonate Sediments and their Diagenesis, Elsevier, Amsterdam, 658 p. Black, M., 1933, The Precipitation of Calcium Carbonate on the Great Bahama Bank, Geol. Mag. v. 70, pp 455-466. Boardman, M R., Neumann, A.C. and Rasmussen, K.A. 1989, Holocene Sea Level in the Bahamas, In: Proc. Fourth Symp Geol. Bahamas, pp 45-52. 85 Boss, S.K., 1994 Early Sequence Evolution of Carbonate Platforms: An Actualistic Model from Northern Great Bahama Bank Unpubl. Ph.D dissertation, U niv. North Carolina, Chapel Hill 675 p. Boss, S.K. and Neumann, A.C ., 1993 Physical Versus Chemical Processes of "Whitings" Formation in the Bahamas, Carbonates and Evaporites, v. 8 (2), pp. 135-148 Broecker, W S. and Takahashi, T., 1966 Calcium Carbonate Precipitation on the Bahama Banks Journal of Geophysical Research, v. 71, pp 1575-1602. Carver, R.E. 1971 Procedures in Sedimentary Petrology, Wiley Interscience, New York, pp. 367-409. Cloud, Jr., P.E ., 1955, Bahama Banks West of Andros Island (Abstr.), GSA Bulletin, v. 66, p 1542 Cloud, Jr., P.E., 1962, Environment of Calcium Carbonate Deposition West of Andros Island, Bahamas, U S G.S Professional Paper, 350, pp 1-138.

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86 Davis, R.A., 1965, Willow River Dolomite; Ordovician Analog of Modem Algal Stromatolite Enviromnents, Journal of Geology, v. 74, pp. 908-923. Davis, R.A., 1975, Intertidal and Associated Deposits of the Prairie du Chien Group (Lower Ordovician) in The Upper Mississippi Valley, In: Ginsburg, R.N (ed ), Tidal Deposits, A Casebook ofRecent Examples and Fossil Counterparts, Springer Verlag, New York, pp. 299-306. Demicco, R.V., 1983, Lenticular and Wavy Bedded Carbonate Ribbon-Rocks of the Upper Cambrian Conococheague Limestone, Western Maryland, Jour. Sed. Petrology, v. 53, pp. 1121-1132. Dietz, R.S Holden, J C and Sproll, W P., 1970 Geotectonic Evolution and Subsistence of Bahama Platform, GSA Bulletin, v 81, pp. 1915-1928. Dunham, R.J., 1962, Classification of Carbonate Rocks According to Depositional Texture, In: Ham, W E. (ed ), Classification of Carbonate Rocks-A Symposium, Amer. Assoc. Petroleum Geol. Memoir 1, pp. 108-121. Eberli, G.P., and Ginsburg, R.N., 1989, Cenozoic Progradation ofNorthwestem Great Bahama Bank, A Record of Lateral Platform Growth and Sealevel Fluctuations, SEPM Special Pub. 44, pp. 339-351. Eberli, G.P Kendall, C.G.St.C., Moore, P Whittle, G.L., and Cannon, R., 1994, Testing a Seismic Interpretation of Great Bahama Bank with a Computer Simulation, AAPG Bulletin, v. 78(6), pp. 981-1004. Enos, P., 1974a, Surface Sediment Facies of the Florida-Bahamas Plateau, GSA, Map Series, MC-5, 4 p. Enos, P., 1974b, Reefs Platforms, and Basins ofMiddle Cretaceous in Northeast Mexico, AAPG Bulletin, v 58, pp. 800-809. Enos, P., 1983, ShelfEnviromnent, In: Carbonate Depositional Enviromnents, Amer. Assoc. Petroleum Geol. Memoir 33, pp. 268-295. Fisher, W.L., and Rodda, P.U., 1969, Edwards Formation (Lower Cretaceous), Texas: Dolomitization in a Carbonate Platform System, AAPG Bulletin, v. 53, pp. 55-72. Folk, R.L., 1962, Spectral Subdivision of Limestone Types, In: Classification of Carbonate Rocks, Amer. Assoc. Petroleum Geol. Memoir 1, pp. 62-84 Gebelein, C.D., 1974, Guidebook for Modem Bahamian Platform Enviromnents, GSA Annual Mtg., Fieldtrip Guide, 93 p

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87 Ginsburg, R.N., 1956, Environmental Relationships of Grain Size and Constituent Particle in some South Florida Carbonate Sediments, AAPG Bulletin, v. 40, pp. 2384. 2427. Ginsburg, R.N., 1960, Ancient Analogs of recent Stromatolites 21st Intemat. Geol. Cong. Rept., pt. 22, pl2635, as seen in Imbrie, J., and Buchanan, H., 1965, Sedimentary Structures in Modem Carbonate Sands of the Bahamas, In: Primary Sedimentary Structures and their Hydrodynamic Interpretation: SEPM Special Pub 12, pp. 149-172 Ginsburg, R.N., and Lowenstam, H A., 1958, The Influence ofMarine Bottom Communities on the Depositional Environment of Sediments, Journal of Geology, v. 66, pp. 310-318 Hardie, L.A 1977, Sedimentation on the Modem Carbonate Tidal Flats of Northwestern Andros Island, Bahamas, Johns Hopkins Studies in Geology, 22, Johns Hopkins Univ. Press, Baltimore. Hine, A.C 1983, Relict Sand Bodies and Bedforms ofthe Northern Bahamas: Evidence of Extensive Early Holocene Sand Transport, In: Peryt T.M. (ed.), Coated Grains, Heidelberg Springer-Verlag, pp. 116-131. Hine, A.C and Neumann, A.C 1977, Shallow Carbonate-Bank-Margin Growth and Structure, Little Bahama Bank, Bahamas, AAPG Bulletin, v. 61, pp. 376-405. Illing, L. V., 1954, Bahamian Calcareous Sands, AAPG Bulletin, v. 38, pp. 1-95. Imbrie, J., and Buchanan, H., 1965, Sedimentary Structures in Modem Carbonate Sands of the Bahamas, In: Primary Sedimentary Structures and their Hydrodynamic Interpretation, SEPM Special Pub.l2, pp. 149-172 Jones, B., and Desrochers, A., 1992, Shallow Platform Carbonates, In: Walker, R.G ., and James, N P. (eds ), Facies Models, pp. 277-301. Ladd, J W., and Sheridan R.E ., 1987, Seismic Stratigraphy of the Bahamas, AAPG Bulletin, v. 71, pp 719-736. Lanesky, D.E. Logan B W. Brown, R.G., and Hine A.C. 1979 A new Approach to Portable Vibracoring Underwater and on Land, Jour. Sed. Petrology, v. 49, pp. 146-149. Logan B.W., Rez ak, R., and Ginsburg, R N 1964, Classification and Environmental Significance of Algal Stromatolites Journal of Geology v. 72, pp 68-83

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Major, R.P Bebout D G. and Harris P M., In Press Recent Evolution of a Bahamian Ooid Shoal : Effects ofHurricane Andrew 21p 88 Morse, J W Thurmond V Brown, E and Ostlund, H G 1984 The Carbonate Chemistry of Grand Bahama Bank Waters : after 18 years another look Journal of Geophysical Research, v. 89 pp 3604-3614 Neumann, A. C., and Land, L.S 1975 Lime Mud Depos i tion and Calcareous Algae in the Bight of Abaco, Bahamas: A Budget, Jour. Sed. Petrology v 45 pp 763786 Newell, N D. 1955 Bahamian Platforms In: Crust of the Earth : Geol. Soc. of Amer. Special Paper 62, pp 303-316 Newell N D. and Rigby, K 1957, Geological Studies on the Great Bahama Bank, In : Regional Aspects of Carbonate Deposition, SEPM Special Pub. 5, pp. 15-72 Newell, N.D., Imbrie J Purdy, E.G and Thurber, D T ., 1959 Organism Communities and Bottom Facies, Great Bahama Bank, Amer. Mus Nat. Hist. Bulletin, v. 117, pp. 177-228. Newell, N.D., Purdy, E.G ., and Imbrie, J., 1960, Bahamian Oolite Sand, Journal of Geology, v 68, pp. 481-485. Purdy E G 1963a, Recent Calcium Carbonate Facies of the Great Bahama Bank. 1. Petrography and Reaction Groups Journal of Geology v 71(3), 334-354 Purdy E G., 1963b Recent Calcium Carbonate Facies of the Great Bahama Bank. 2 Sedimentary Facies Journal of Geology, v 71(3), 472-497. Purdy, E.G., and Imbrie J., 1964, Carbonate Sediments, Great Bahama Bank, Geol. Soc. Amer. Guidebook no. 2, Miami Beach Meeting, 66 p Robbins, L.L. and Blackwelder, P L., 1990, Origin of Whitings: A Biologically Induced Nonskeletal Mechanism AAPG Bulletin, v. 74, p 749 Robbins, L.L. and Blac kwelder P L., 1992, Biochemical and Ultrastructural Evidence for the Origin of Whitings : A B i ologically Induced Calcium Carbonate Precip i tation Mechanism Geology v 20, pp 464 468 Robbins, L.L. and Yates K.K. 1992 Role ofMicrorganisms in the Production of Lime Mud and Implications for Interpretation of Ancient Micrite Deposits North American Paleontological Conference, Chicago

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Scholle, P .A., 1978, A Color Illustrated Guide to Carbonate Rock Constituents, Textures, Cements, and Porosities, Amer. Assoc Petroleum Geol. Memoir 27, 241 p Sellwood, B W. 1986, Shallow-Marine Carbonate Environments In: Reading, H G. (ed.), Sedimentary Environments and Facies, Blackwell Scientific, Oxford, 615 p 89 Sheridan R E ., Mullins, H.T Austin, J A., Jr., Ball, M M., and Ladd J W 1988 Geology and Geophysics ofthe Bahamas : In: Sheridan, R.E and Grow, J.A. (eds.), The Geology ofNorth America, Volume 1-2, The Atlantic Continental Margin, U S Geological Society of America pp. 329-364. Shinn, E A. and Ginsburg, R.N. 1964 Formation of Recent Dolomite in Florida and the Bahamas (abstract) AAPG Bulletin v. 48 p. 547 Shinn, E A., 1983, Tidal Flat Environments, In Scholle, P.A. (ed.), Carbonate Depositional Environments, Amer. Assoc Petroleum Geol. Memoir 33, pp. 173-210. Smith C.L., 1940 The Great Bahama Banlc I General Hydrographic and Chemical Factors, Journal of Marine Research v 3, pp. 1 31. Smith, G. L., Byers, C. W and Dott, R. H ., Jr 1993, Sequence stratigraphy of the Lower Ordovician Prairie du Chien Group on the Wisconsin Arch and in the Michigan Basin, AAPG Bulletin, v 77 pp. 49-67. Stone, G W and Morgan, J.P., 1992, Jack-up Pontoon Barge for Vibracoring in Shallow Water, Jour Sed Petrology, v 62(4), p. 739-741. Taft, W H and Harbaugh J.W 1964, Modem Carbonate Sediments of Southern Florida, Bahamas and Espiritu Santo Island, Baja California, Stanford Univ Publ. Geol. Sci v. 8 pp 1-133. Tao, Yucong, 1994 Whitings on the Great Bahama Bank: Distribution in Space and Time Using Space Shuttle Photographs, Unpublished Masters thesis, University of South Florida, Tampa FL, 77 p Traverse, A. and Ginsburg, R.N 1966 Palynology of the Surface Sediments of Great Bahama Bank as Related to Water Movement and Sedimentation, Marine Geology, v 4(6), pp. 417-459. Tucker, M E and Wright P V. 1990. Geological Background to Carbonate Sedimentation In: Carbonate Sedimentology, Blackwell Scientific Publications, London, pp 28-69

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90 Uchupi, E Milliman, J.O Luyendyk, B P Bowin C.O. and Emery K O. 1971, Structure and Origin of the Southeastern Bahamas, AAPG Bulletin v 55, pp. 687704 Wilber, R.J. Milliman, J D. and Halley R.B. 1990, Accumulation of Bank-Top Sediment on the Western Slope of the Great Bahama Bank : Rapid Progradat ion of a Carbonate Megabank, Geology, v 18, pp 970 974. Williams H ., Turner F J., and Gilbert C M 1982, Petrography : An Introduction to the Study of Rocks in Thin Section, W H. Freeman and Company, San Francisco, 626p Wilson, J.L., 1975, Carbonate Facies in Geologic History, Springer-Verlag, New York, 471 p Winland H D., and Mathews, R.K., 1974, Origin and Significance ofGrapestone Bahama Islands, Jour Sed Petrology, v. 44, pp 921-927. Yates, K.K. 1996, Microb i al Precipitation of Calcium Carbonate: A Potential Mechanism for Lime -Mud Production, Unpublished Ph. D dissertation, University of South Florida, Tampa, FL, 198 p.

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9 1 APPENDICES

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92 APPENDIX 1. CORE LOGS The following pages contain logs of cores taken along the five transects on the northern Great Bahama Bank (see figure 5 for locations). The first page explains the general format and symbols for the core logs. The scale on the left, in meters, represents the distance below the sediment/water interface that the core penetrated. Latitude and longitude of each core are added for ease of location Correction for the compaction, shown in the upper left, is already added to the log, therefore cores are logged at true statigraphic thickness. This thickness is used in estimating accumulation rates for several cores, as discussed previously. Also included is the water depth at each core location Pattern on the logs represent identified facies within each core. The few sedimentary structures and large fossils are represented by various symbols, accompanied by genus names where applicable. These are located in the section labeled 'other.' Data used to determine facies designations are represented by percents of mud, sand, and gravel, followed by percents of the six most common grain types. The right-hand most column identifies the facies designation for each sample location from within the core. Where applicable, brief descriptions of the petrography of hardground samples lies to the right of its appropriate position in the core. Complete data for individual samples can be located in other Appendices.

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APPENDIX 1 (Continued) Core# (m) 0 0.5 1.0 1.5 Latitude: Longitude : 0 0 .... . ....................... :.:.:.:.:.:.: . .... facie s change bivalves mud laminations V/V( Thalassia roots Ot he r Cerithidae C hi one Lucinidae Atyidae Cardidae Compaction (em): % Compaction : Water Depth : c., oz,o.o ;t}'r.o.J c., X v ;;l'o., '-' <:f p /o/m/g/h/1 p ercent organic matter coral fragments echinoderm fragments d Gastropod IW Lithified Sediment H Hardground fragment 93 Facies Pellet /Grapes tone Pellet! Halimeda Pellet Pellet /Micritized Grain Halimeda Pellet Mud M ud P l eistocene hardground

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APPENDIX 1. (Continued) STA 1 Latitude: 25 .95 N Core# -Longitude: 79.09 W percent (m) 0 ..... ---'"""""'-.63/99.37/0 0.5 1.0 1.5 \'r . . . . . 0 . . . . Vt .. .-.....,. : . :.: ....... 2.27/82 95114.78 LUCINIDAE 1 04/91.3917.57 CERiTHIDAE 1.54/86.79111.67 CHIONE LUCINIDAE CERiTHIDAE Compaction (em): 71.5 em %Comp ac tion : 27.7% Water Depth: 5 18m p /o/m/g/h/1 percent 6416112/911/4 Pellet 53/3110/6/12/0 Pellet 54/2/ 16 /5/8/4 P e llet 78/6/9/2/0/3 Pellet 57/3/1118/3/9 Pellet 94

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APPENDIX 1. (Continued) Core# STA-2 Latitude: 25.61 N Longitude : 78 .91 W (m) 0 0.5 m/sl'l percent 72/98.92/.36 ( . . 1--1.82/72 2/25 98 Compaction (em): 34 em %Compaction : 30.9% Water Depth : 5 79m p/olmlg!hn percent 50/0117/9/9/8 Pellet 56/0/13/2/6117 Pellet rock: highl y cemen ted oopelbiosparite 20,910yrsBP Biopelsparite Pleistocene hardground 1.0

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APPENDIX 1. (Continued) Latitude: 25.07 N Compaction (em): 52 em % Compaction: 18.9% Water Depth: 5.18 m Core# STA-3 Longitude: 78.66 W (m) 0 0.5 1.0 1.5 2.0 :vr: . .. . . 0 : . ( H .). '( .. . . .) per cent p/o/m/glh/1 percent 9.39/90 14/ .47 61101141212/5 3.25/94 65/2.10 70/0/5f218/6 CERiTHIDAE 5 29/92.9911 .72 1210/4f21514 LUCINIDAE 2 32192 54/5 .14 83/0 / 11/3 /0/ 1 partially r ecrystallized bi v alve fragment Pellet Pellet Pellet Pellet 96

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APPENDIX 1. ( Continued) Core# STA-4 Latitude : 25 1 9.97 N Longitude : 78.01 W rnls/g percent (m) 0 --------2.79/96.40/.81 : \ir:: : : Y1 ... :: : : :Vi: : : \lr.: : 0 . . . o.5 : : : :\Jr: 6.11/93.81/.08 1.0 coral frags 4.25 /95 .43/ 32 3.32192.27/4.41 LUCINIDAE 1.94/91.27/6 .79 : JI: : .. Compaction (em): 25.5 em % Compaction: 10. 1 % Water Depth : 4.45 m p/o/rnlg/b/l perc ent 8111/8/31111 Pellet 68/1/15/0/1/4 Pellet 691117/0n/5 Pellet 721 1 /12/3/6/0 Pellet 85/017/1/3/ 1 Pellet 97

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APPENDIX 1. (Continued) Core# STA-19 Latitude: 25.99 N Longitude : 78.99 W m/s/fl percent (m) 0 : :::::: 29.6170. 07/.33 o.s iii:i:li:i:i -...... : : :Vi:: : 1---12.16/87.4/.44 1.0 -: : : : : : : :: : ::: ::: :"Y(: : : : : : : : : : : : : : : 1.5 : : : : : : : ::: : ::: -: : : : : : : 0 0 I-9 14/88 .1912.67 -::: :(:: . . """" -Compaction (em): 37 em %Compaction: 19.0 % Water Depth : 4.66 m p/o/m/fl/h/1 percent 66/0/ I 5/0/8/0 Pellet Mud 67/011210/6/0 Pellet Mud 7211/ll/0/0/0 Pellet 64/0/13/0/0/0 Pellet 98

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APPENDIX 1. (Continued) Core# STA-20 Latitude: 25.40 N Longitude: 78.41 W percent (m) O Ei::I::Ei::I:I:+--25.69173.881.43 36.59/63.05/.36 0 5 36 .18163.401.4 2 ======= -...... . . . . -...... . . . . . . . 1---18.27/81.55/ .18 -rrrrrrr 1.0 1---18.06/81.55/.39 ....,__ 15.60/83.86/.54 1.5 16 .28/82.58/ 1.14 17.26/79.0/3.74 2.0 -Compaction (em): 25 em % Compaction: 12.2 % Water Depth : 5.15 m plolml&fhD percent 501012511/5/2 Pellet Mud 6110/2 7/0/1 /0 Pellet Mud 4 7/0/31/011 0/0 Pellet Mud 69/0/19/0/3/0 Pellet 66/0119/0/210 Pellet Mud 68/0/ 17/0 /5/0 Pellet 59/0/18/011210 Pellet 99 67/0/23/0/210 Pellet/Micritized Grain 68/0/2210/3/0 Pellet/Micritized Grain

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APPENDIX 1. (Continued) Core# GBB-1 Latitude: 25.231 N Longitude: 78.175 W Compaction (em): 18cm %Compaction : 8.78% Water Depth : 2.44m (m) 0 0 5 1.0 1.5 m/s/2 percent p/olml&lhll percent 23.9/75 78/ 32 48/0/30/0/6/0 : ll!l!!!l!i:llll 31.42/66.67/1.91 54/0/20/017/0 27.38/70.8811.74 4110/2 4/0/6/0 28.17/70 94/ .89 CERITHIDAE 41/0116/0/5/1 CERITHIDAE ..t--53.13/45 .3411.53 CERITHIDAE 31/0/22/0/4/0 7/0/19/0/4/7 CERITHIDAE Pellet Mud Pellet Mud Pellet Mud Pellet Mud Mud Mud 100 Highl y cemented pel s parite Pleistocene hardground

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101 APP E NDI X 1. ( Continu e d ) Core# GBB-2 (m) 0 0.5 1.0 1.5 2.0 ---- =- : : : : . :r. Latitude: 25.8 1 N Longitude: 78 90 W Compaction (e m): 61cm % Compaction : 25.8 % Water Depth: 4.88m m/s/g per c e n t p /o/m/g/h/1 percent 4 6 /8 05/8 I 7. .34 66/ 0/211111/7 Pellet /Micriti ze d Grain 9.49/86.07/4 .44 44 /2/33/0/8/11 Pelle t /Mi critized Gr a in 6 .2 3/89 86/3 91 29/0/38/0110/9 Pelle t /Mi c riti zed Grain 9 34/88. 44/2.22 5 0 /0/27/0/ 9 / 1 Pellet /Mi critized Gra in 2.50/85.82111.68 50/0118/6/ 4/14 Pellet Foram and b i va l ve bearin g p e lsparite 7.48/82.07110.45 62/0/17/0/8/7 Pellet Foram and biva l ve bearin g p e lsparite

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APPENDIX 1. (Continued) Core# GBB-3 Latitude : 25.53 N Longitude : 78.17 W m/sl'l percent (m) -...... . . . . 1--11.27/87.11/1.62 -..... . 0 5 --.... '. : r. : : 1---..(j' .18/93 56/ 26 -...... -...... -. .... 1 0 -...... -...... -. . ... -...... . . . . 1---4.22/94.05/1.73 -. '-'""' . 1.5 --.... . -..... . ::::::: : : : : : : : 1---2.71193.55/ 3 .74 Compaction (em) : 25cm %Compaction: 12.02% WaterDepth: 4.57m p/o/m/'lfh/1 percent 102 Pellet Micritized Grain 6 6/3/17/0/2/0 Pellet 67/0/18/511/ 0 Pellet 58/0/16/4/ 8/ 8 Pellet 68/0/1117/4 / 0 Pellet 2 .0... r.-... LAEVICARDIUM -

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APPENDIX !.(Continued) Latitude : 25o12.98 N Core# GBB-4 Longitude : 78 22 W (m) 0 0 5 1.0 1.5 2.0 2.5 : r.: :"\ A e mls/g percent 17. 67/81.77/.56 CERITIDDAE 7 56/91.13/1.31 CERITHlDAE Compaction (em): 46.5cm %Compaction: 18. 3 % Water Depth: 5.18m plolmlglh/l p ercent Pellet /Micritized Grain 62101 19/0/0 / 3 Pellet 67/0/19/0/8/0 P e llet 58/1/20/1/9/0 P e llet /Micritized Grain 76!0112JOI 1 / 0 Pellet 103

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APPENDIX 1. (Continued) Core# GBB-5 (rn) Latitude: 25.11 N Longitude: 78.44 W percent 0 --.-.-.-.-. -r---1.18/98.64/.18 \v . Vt -..... ... "r .... . -.... . 1---8.47/91.13/. 40 0 5 --..... -::: r-:: ...... 1---10. 10/89.811.09 -. 1.0 I 0.53/89 38/.09 -..... -..... Compaction (em): 54 em % Compaction : 22.8% Water Depth: 5.33 m percent 7 5/0/15/0/2/0 Pellet 66/0/20/0/3/0 Pellet 52/1/20/0/3/11 Pellet 104 591013010/4/0 Pellet /Micritized Grain 70/0/17/0 / 2/0 Pellet 1.5 :i'.J. +---4.11193.70/2 .19 coralline rubbl e -i--2 .11196.92/.97 7 0/0/18/0/2/0 Pellet 2.0 ---

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105 APPENDIX 1. (Continued) Core # GBB-6 Latitude: 25 .10 N Compaction (em): 78 em Longitude: 79.82 w % Compaction: 28.6% Water Depth : .40m m/s/& (2/o/ml&lhO 12ercent Facies (m) 0 .11/99.68/ .21 37/2111/3/3210 Pellet/ Halimeda --0 5 --. 23/99 45/ 32 45/4/19/2118/0 Pellet --1.0 --.88/98.83/.29 54/5/1611115/0 Pellet --1.5 LUCINIDAE LUCINIDAE ---.60/98.7 9/ .6 1 45/3 /8/0/28/ 0 Pellet/ Halimeda 2.0 c ontinued on next page

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APPENDIX 1. (Continued) Core# GBB-6 cont. percent LUCINIDAE CERITHIDAE 106 p/o/m/g/h/1 p e rcent 39/0/16/4/24/0 Pellet/ Halimeda

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107 co ntinued o n n ext pa ge

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APPENDIX !.(Continued) Core # GBB-7 cont. mlsl& percent .56/98.521.92 58/98 .77/.65 LUCINIDAE 108 p/o/m/g/h/1 percent 33/3/16/4/25/4 Pellet/ Halimeda 35/2115/1/26/9 Pellet! Halimeda

PAGE 120

109

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APPENDIX 1. (Continued) Core # BB2-2 Latitude : 24.64 N Longitude: 79.94 W (m) 0 0 ....... .................... 0 0 0 0 i m/s/2 percent o s m:l:l.:liii 30 98/6 7.86/ 1.16 :::::: :::::::: 1.0 :t-----16.81174.5118.68 1.5 Compaction (em): 24 em % Compaction: 16.4% Water Depth : 6.10 m p/o /m/2/b/1 percent 110 47/0/18/0/2110 Pellet! Halimeda 4210/23/0 /2 3/0 Pellet Mud 34/0/13/0/36/0 Pellet! Halimeda

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APPENDIX 1. (Continued) Core# BB2-3 Latitude: 24.10 N Longitude : 78.30 W per c ent (m) 0 34 72/63 15/2 .13 MANICENA SP 0.5 Compaction (em) : 0 em % Compaction: 0 % Water Depth : 6.35 m p / o/m/g/h/1 percent 4 7/0114/0/27/0 Pellet Mud 111

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APPENDIX 1. (Continued) Core# BB2-4 Latitude: 24 08 N Longitude: 78.37 W (m) 0 0 5 percent Organic Patch Compaction (em): 16 em % Compaction: 10.2% Water Depth: 4.60 m p/o/m/fdhl! percent 5 0 / 1 /15/0/17/0 Pellet Mud 27/0/34/0/17/0 Mud 112 1.0 6/0/ 18/0/0173 Plei s t ocene hard g round Hardground rubbl e and mud 28,630 yrs BP Le s s alte red pelsparite 1.5

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113 APPENDIX 1. (Continued) Core# BB2-5 (m) 0 0.5 1.0 1.5 ...... .................... . . . Latitude: 24.10 N Longitude: 78 84 W Compaction (ern): 7 ern %Compaction: 4.8% Water Depth: 3.90 rn m/s/E percent plolmiE!bll percent 23.81/74.65/1.54 64/0/11 /0116/0 Pellet Mud CERlTHIDAE t---45.77/49.78/4 .4 5 37/0115/0112112 Pellet Mud CERlTHIDAE 29/0/17/0116/5 Mud .... yrs BP Highly altered pe1sparite Pleistocene hardground

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APPENDIX 1. (Continued) .Core# BB2-6 Latitude: 24.04 N Longitude: 78.34W Compaction (em): NA % Compaction: NA WaterDepth: 3.04m percent (m) Hardground exposed at the surface Halimeda bearing pelsparite possib l e soil horizons 114

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APPENDIX 1. (Continued) .Core # BB2-7 Latitude: 24.70 N Longitude: 78.80 W (m) 0 0.5 1.0 1.5 rn/s/2 percent :: Y( 1---19.73179.64/ .63 i..___ 28.07/68 .71/ 3 22 CERITHIDAE 31.79/67 24/ 9 7 CERITHIDAE Compaction (em) : ND % Compaction: ND Water Depth: 3.35 m p/o/m/2/hfl percent 115 Pellet/Micritized Grain 7 8/0/13/0/2/0 Pellet 65/0/14/0/5 / 0 Pellet Mud 5 1/0 /18/ 0 /16/ 0 Pellet Mud

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APPENDIX 1. (Co n tinued) Core# BB3-1 Latitude : 25.99 N Longitude : 78.00 W Compaction (em): 51.2 em % Compaction : 31.0% Water Depth : 8 54 m m/s/f: percent p/o/m/g/h!l p ercent ( m) 0 ---------1 .24/.89/98.49 66/011217/4/5 Pellet 1---1 12198.83/.05 54/0115/15/0/8 Pellet 0 5 -t--1 59/92.20/6.2 1 59/0112111/517 Pellet . . -CERUTHIIDAE 1.0 --. ( . Echinoderm F r agme nt -. Echinoderm Fragment (:: 1---1.0/89.69/9.31 5210110/9/ 6/ 1 4 Pellet Lar ge Arc S h ell -.. 1 5 ...;..'...;..'....;.;......;..'-'-' 116

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APPENDIX 1. (Continued) Core # BB3-3 Latitude: 25.94 N Longitude: 78.02 W per cent Compaction (em): 48 e m %Compaction: 2 5 .9% Water Depth: 3. 96 m p/o/m /gfh/1 percent 118 Pellet/Grapestone 0.5 1.0 1.5 2.0 : :(:: : 1---6.17/83.02110.8 1 35/0/16/4/6/28 . . . . 1---1.19176.13/22 68 .. ( .. . .. 2.15/80.44/17.41 3,530 yrs BP . . . .1--2 73/93 55/3.72 LUCINIDAE 36/0/6/11/2/34 CHIONE 39/ 1 /8/11/3/29 ATYIDAE Both foram and bivalve bearing pelsparites 35/2/917/ 1 3/27 CERITHIDAE Pellet Pellet Pellet Pellet

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APPENDIX 1. (Continued) Core# BB3-4 Latitude: 25.14 N Longitude: 78.85 W Compaction (em): 37.5 em %Compaction : 24.3% Water Depth: 6.10 m 119 mlsl" percent p/o/m/g/h/1 percent (m) 0 0.5 1.0 l---7 96/91.58/.46 2.4/93.96/3 .64 LUCINIDAE Articulated Arc CHIONE Echinoderm Frags ATYIDAE 5311116/9/1 /9 47/0114 /5/9/12 64/0/8/417/12 Pellet/Grape s tone Pellet Pellet Pellet foram and bivalve bearing pels parite "....:/ CARDIDAE 2.74/95 6 !11. 65 61/0 / 9/9/5/11 Pellet 1.5

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APPENDIX 1. (Continued) Core # BB3-5 Latitude : 25o26 98 N Longitude : 78.92 W Compaction (e m): 31 em % Compaction : 14.1 % Water Depth: 5 79 m (m) 0 0.5 1.0 1.5 2.0 m/s/2 per ce nt --------2 12/97.88/ 0 0 :A .. e :(: . 4 44/95.46 / .10 4.48/93 .7611. 76 ..--5 56/93 .3711. 07 r-----5.80/87 .0417.16 p /o/m/g/h/1 percent 87/0/1/2/4/1 71/0/6/2/1112 CERiTHIDAE 8 1 /0/4/2/5/4 70/2/8/2/317 CHIONE 75/0/5/0/3/6 s parite grians recrystallized and un identifia bl e CHIONE Pellet Pe llet Pellet Pell e t Pellet 120

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APPENDIX 1. (Continued) Core# BB3-6 Latitude: 25.00 N Lon git ude: 79 .9 3 W ( m ) 0-----0 5 1.0 2 0 . . :\'r . . ... 0 . . . :: :v. m/s/jl perc e nt 2 29/97 34/.37 .4 07/94 92/1 .01 6 04/91.86/2. 10 3.83/89.0517 .12 3 91/94.79/1.30 CERiTHIDAE LUCINIDAE Compaction (em): 29.5 em % Compaction: 1 2.1% Water Depth : 7.32 m plo l ml&lhll p ercen t 79/817/ 1/1/0 Pellet 78/4 17/3/2/0 Pell e t 83/6/6/3/0/0 P e llet 8 0 / 1 /3/3/3/ 4 Pellet 78/2/6/2/6/0 Pellet :.....;..LUCINIDAE 3 7 4 /65 93130 33 60/317/0/2/27 Pe ll e t 121

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122 APPENDIX 1. (Continued) Core# BB3-7 (m) 0 0.5 1.0 : ;j!! a<..n! -: : :. : Latitude : 24.98 N Longitude: 78.10 W m/s/g percent 10.89/88.06/1.05 23.6176 17/ 23 29.17/67.61/3.22 38. 11/ 54.52/7.37 Compaction (em): 9 em %Compactio n : 7.8% Water Depth : 2.74 m p/o/m/g/h/1 percent 67/0/24/011/0 Pellet/Micritized Grain 70/0/13/1/2/0 Pellet Mud 58/0/24/0/3/7 Pellet Mud 62/0/15/0/4/0 Pellet Mud biopelsparite with micrite stringers MUREX < 30,400 yrs BP Pleistocene hardground Foram and bivalve bearing pelsparite

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APPENDIX 1. (Continued) Core # BB3-8 Latitude: 24.07 N Longitude: 78.87 W m/s/g per ce nt (m) o ...... --1---22.41174.09/3.5 0.5 1---26.92172.85/.23 1.0 1----27.67170.93/1.4 1.5 34 57/64.07/1.36 CERiTHIDAE 2.0 Compaction (e m) : 23 em % Compaction: 12.1% Water Depth : 5.18m p/o/m/g/h/1 percent Pellet 64/0/14/0/3/ II Pellet Mud 72/0116/0/5/0 Pellet Mud 57/0/14/0/12/11 Pellet Mud 56/0/14 / 0 / 11/2 Pellet Mud 4 7/0/24/0/311 Pellet Mud 123

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punolgp.I1Hj r;9/L/OIZ l/0/L aJ!-ffidS [ad pazmu1sh.I:>aJ A(f-!g!ll O I tll pnw 01/V/0/W0/6 pnw 0/Z/0/Z /0/8 r; pnw r; I /r;/0/0/0/917 U4fllfWJOjd w I L'9 M. %0'0I W:) I : (W:)) t' untnr; ---1 6ur;covt9or; 80 a o r;tr;9v ... ... 0 (w) M. I6'9t08L N OI 6:9: # gJO:) (panunuo;::>) r XIQN'3:ddV

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0 1 L/018UO / Or; pnw U 9 /0 /8U0 /t;r; V4/JJwJoJd w I c 9 :tndda 1d1-e M. %"It :i:i:i:i:i:+:ilr;n/8! ( m o u : j : j:-j-:j:j:j:jl-... 0 ....... . ........ ...... ... ... 0 0 "' "' "' "' ' ' ' / / / / / / ; ' ' ' / / / / / / / ' ' ' / / / / / / ' ' ' / 'df / / / / / / / / / ,._ ' ' ' ' gr;t6r; Itr;sL9--i,/'/ '/'/'/ a/SJW / / / / / / / / / / ' ' ' / / / .;. / / ' ' / / / / / / "'-' ' ' ' / / / / / / / ' ' ' / / / / / ; / ' ' ' ol 0 (w) M. 0 N 66" I : dpmn-e'l OIgg # (panunuo:J) r XIGN3ddV

PAGE 137

126 APPENDIX 2. STATISTICAL DATA FOR SURFACE AND CORE SAMPLES The following table summarizes all statistical data computed from grain size analyses for surface samples core samples, control samples and data gathered and utilized from Boss (1994) Sample numbers are followed by latitude and longitude for all surface samples, as well as the uppermost sample from each core. Statistical data include percent gravel sand and mud median grain size, mean grain size, standard deviation, and skewness Median grain sizes are absent from data used from Boss, (1994)

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APPENDIX 2. (Co ntinu ed) Great Bahama Bank-Surface Sediment Samples STATISTICAL DATA Sample# latitude longitude % gravel % sand ss-1 24 51.60 79 02 .83 0 06 97 .93 ss 2 24 48 75 79 03 .01 0 09 95 86 ss-3 24 47 .91 79 02 97 7.12 83.51 ss-4 24 46.11 79 03. 02 0.48 91.92 ss-5 24 44. 08 79 03 02 0.21 93 60 ss-6 24 42.18 79 03.02 0.30 89. 09 ss-7 24 40. 10 79 03.01 0 95 87. 32 ss-8 24 40. 08 79 00 .90 0 55 82 07 ss9 24 40.06 7 8 58.64 0 68 74 02 ss-10 24 40. 05 78 56.41 1.04 79 .11 ss-1 1 24 40.03 78 54.2 1 2.53 72. 79 ss-12 24 40.16 78 52 02 1.87 7 9.65 ss-13 2 4 40. 1 5 78 49.83 2.51 79.79 ss1 4 24 40. 1 4 78 47 62 0 .22 79 .19 ss1 5 24 40 .12 78 43.30 0.29 84 .30 s s 1 6 24 40.09 78 40 98 7.22 81.86 ss1 7 24 40.08 78 38 84 1.67 77 29 ss1 8 24 40 1 1 78 35 53 1.39 90 92 ss-19 24 43 07 78 34 68 7.12 70.83 ss 20 24 46.27 78 32.43 1.70 77 .21 ss-21 24 49 05 78 33.05 0 08 86.56 ss-22 24 50.42 78 35. 1 8 0.00 98.55 s s-23 24 51.02 78 38.51 0.05 98 .17 ss 24 24 51.57 7841.81 0.41 8 3 80 s s -25 24 51.99 78 44.08 3.52 55. 85 ss -26 24 52.03 78 47 04 3.26 57 35 ss 27 24 52 .04 78 48 .65 2.32 44.36 ss-28 24 52 03 78 50 88 1.15 48.31 ss-29 24 52 .01 78 53 09 1.66 42. 94 ss-30 24 52 03 78 55.3 1 1.04 40.57 s s-3 1 24 52 02 78 57.53 1.44 52 .19 ss 32 24 52 0 1 78 59 50 0.6 1 54.25 ss-33 24 52.00 79 01.76 0 09 88.49 ss-34 24 52.0 1 79 04.11 0 00 98.48 ss-35 24 52 00 7 9 04 96 0 00 99 1 4 s s -36 24 53.87 79 05.17 0.00 99.14 s s -37 24 55 86 7905. 1 5 0 .14 99 79 ss-38 24 57 92 79 05.15 0.40 99 20 ss 39 25 00. 07 7905.12 0 24 99 62 ss-40 25 02.00 7905. 10 1.95 97 89 ss -41 25 03 .96 79 05 09 2 20 97.47 ss-42 25 05 95 79 05.11 2 86 97.03 ss-43 25 07 96 79 05.0 7 0.87 98.93 ss-44 25 09.97 7 9 05.10 0.98 98 79 ss 45 25 12. 1 8 79 05.05 1.35 98 03 s s -46 25 14. 25 79 05.10 2.18 96 34 127 % mud median mean st. dev s kewness 2 .01 1.67 1.88 0 66 -0.49 4 05 1.74 1.97 0.9 3 -0.24 9. 37 2 .18 2 .00 1.53 -1.58 7 60 2 .01 2.1 4 1.00 -0.68 6 1 9 1.78 2 .01 0 89 -0.46 10. 6 1 2.16 2 .31 0.93 0 78 11.73 2 .15 2.3 1 1.02 -0 99 1 7 .38 1.70 2 05 1.02 -0 52 25.30 1.58 1.89 0 99 -0 30 19.85 1.72 1.96 1.05 0 66 24.68 1.97 2.09 1.20 -1.41 18.48 1.71 1.9 1 1.11 -0 96 1 7 .70 1.70 1.90 1.15 -1.10 20.59 1.97 2 2 1 0.98 0.49 15.4 1 1.69 2 .01 0.98 -0.35 1 0 92 1.32 1.43 1.39 -1.00 21.04 1.69 1.98 1.12 0 88 7 69 1.46 1.66 0 93 -0.74 22 05 1.57 1.62 1.49 -1.16 21.09 2.44 2.34 1.28 -1.06 13.36 1.65 2.01 0 82 0.11 1.45 1.62 1.88 0.65 -0 19 1.78 1.57 1.89 0.70 0 .19 15. 79 1.95 2 .19 0 96 -0 .53 40.63 2.41 2 28 1.46 -1.50 39.39 2 .13 2 08 1.49 -1.16 53.32 2 .26 2 .18 1.50 1 20 50 54 2 0 7 2 .12 1.36 -0. 75 5 5.40 2 32 2 .23 1.43 1.06 58 39 2.42 2.33 1.36 -1.03 46.37 2.16 2 .23 1.29 1.07 45. 1 4 2 .27 2.39 1.13 0 90 1 1.42 1.69 2 00 0 84 -0 07 1.52 1.63 1.87 0 9 1 -0.24 0 8 6 1.74 1.9 1 0 .90 -0.46 0 8 6 1.49 1.71 0.8 8 -0 .20 0 07 1.5 1 1.71 0.83 -0 38 0.40 1.49 1.62 0 98 -0 53 0. 1 4 1.22 1.37 0 9 7 0 .28 0 1 6 1.55 1.59 1.10 -0 94 0 .33 1.59 1.63 1.06 0 98 0.10 1.18 1.26 1.03 0 95 0 20 1.60 1.68 0.9 4 -0 94 0 23 1.40 1.53 0 .96 -0.58 0.62 1.62 1.67 0 07 -0 .83 1.48 1.53 1.65 1.1 4 -0.76 ( contm u ed on next page) Tab l e 5 S t at i st ical d ata from sed i men t o logical ana l yses o n all surface and core sediment samp l es

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APPENDIX 2. (Continued) Table 5. (Continued) Great Bahama Bank-Surfa ce Sediment Samples STATISTICAL DATA Sample# latitude longitude % gravel % sand ss-47 25 16 10 79 05.09 0 20 99 00 ss-48 25 18. 04 79 05.03 0.23 98. 77 s s-49 25 19 95 79 05.03 0 04 99.27 ss-50 25 21.96 79 05.06 0 00 99 69 ss-51 25 24. 02 79 05.04 0 .00 99.89 ss-52 25 26. 14 79 05.01 0.04 99 65 ss-53 25 28 12 79 05 .01 0.05 99 64 s s -54 25 29 99 79 05.02 0.18 99.47 s s -55 25 33.56 79 15.15 0.00 89 98 s s -56 25 44.02 79 02 06 0.10 99 29 ss-57 25 43 96 78 59.43 0.77 98.39 ss-58 25 43 98 78 57 27 8 74 90 70 ss-59 25 44 05 78 55 00 0.00 99 29 s s-60 25 44 .01 78 52 39 0 05 99.34 ss-61 25 43.98 78 50.17 0 .00 99 30 ss-62 25 44. 05 78 47. 97 0.48 99.22 ss-63 25 43.99 78 45 74 0 .00 99 70 ss-64 25 44 02 78 43 52 0 06 99.45 ss-65 25 43 30 78 41.37 0 05 99 25 ss-66 25 42 73 78 39.9 7 0 .90 98 76 ss-67 25 44.09 78 39.83 0.60 99.11 ss 68 25 44.21 78 37.48 23 79 75 .81 s s -69 25 44.08 78 35 28 1.49 97 88 ss7 0 25 44 .05 7 8 33 04 1.64 97 64 ss-71 25 44 08 78 30.99 3.84 95.46 ss-72 25 44 .05 78 28.86 2.55 96 69 s s -73 25 44.03 78 26.60 8.36 91.55 ss-74 25 44.01 78 24.37 6.27 92 90 ss-75 25 44. 03 7822.14 2.62 96 96 ss-76 25 44 00 78 19.98 16.12 83. 23 ss-77 25 41.98 78 19 98 23.80 75 95 ss-78 25 39 97 78 20 .01 7.52 91.91 s s-79 25 37 .97 78 19. 99 2.93 96. 50 ss-80 25 35.87 78 19.96 1.43 98 .33 ss -81 25 33 96 78 20 05 0.54 99 .19 ss-82 25 31.98 78 19 99 4 .83 93. 83 ss-83 25 29.94 78 19. 96 1.27 96 .61 ss-84 25 27.97 78 19.96 1.11 96 26 s s -85 25 26. 94 7 8 20. 02 0.79 97.32 ss-86 25 26 98 78 22.56 0 67 97.59 s s -87 25 27 03 78 24 64 5 80 92 08 ss-88 25 27 .01 78 26.88 0.44 96.67 ss-89 25 27 .21 78 29.10 0.60 96.92 s s -90 25 27 16 78 31. 6 4 0.79 95 54 ss-91 25 27.17 78 33.53 0.00 99 30 s s -92 25 27 .11 78 35 70 0.00 98 29 ss-93 2 5 27 .14 78 3 7.85 0 08 98 0 7 ss-94 25 27 22 7 8 40. 22 0.59 98 68 128 % mud median mean st. dev. skewness 0 80 1.51 1.70 0.83 -0 .46 1.00 1.70 1.9 4 0 78 -0.50 0 69 1.49 1.70 0 67 -0.40 0 .31 1.74 1.95 0.63 -0 76 0 .11 1.29 1.47 0 63 -0 .31 0 .31 1.32 1.49 0.65 -0.50 0.31 1.41 1.61 0 65 -0.39 0.35 1.56 1.81 0.59 -0.56 10. 02 2.01 2.30 0.95 -0.38 0 .61 1.50 1.72 0.77 -0 16 0 84 1.54 1.70 0.90 -0 73 0.56 1.39 1.30 1.33 -1.42 0 .71 1.13 1.34 0.75 0.05 0 .61 1.35 1.56 0.77 -0.14 0 70 1.51 1.70 0 79 -0.45 0.30 1.42 1.59 0.81 -0 6 7 0 30 1.11 1.32 0.74 -0 .10 0.49 0 98 1.20 0 80 -0 .01 0 70 1.42 1.66 0.84 -0.11 0.34 1.28 1.44 0.89 -0 65 0 29 0.35 1.54 0 80 -0 67 0.40 0.76 0.48 1.62 -0 64 0.63 1.43 1.54 0.90 -1.02 0 72 1.17 1.34 0.91 -0.79 0 70 1.21 1.32 1.02 -1.20 0 76 1.09 1.23 0 93 -0 79 0.09 1.33 1.22 1.25 -1.54 0 83 1.42 1.40 1.19 -1.19 0.42 1.26 1.39 1.07 0 60 0 .65 0 63 0.68 1.47 -0.4 7 0 25 0 84 0.52 1.67 -0 69 0 57 1.15 1.17 1.26 -0.91 0 57 1.39 1.50 1.03 -0 95 0.24 1.40 1.52 0 .96 -0 .74 0 27 1.34 1.49 0 .91 -0.3 3 1.34 0.48 0.76 1.10 0 .07 2.12 1.12 1.35 1.01 -0.41 2.63 0 83 1.14 1.06 0.17 1.89 0 63 0.96 1.00 0.36 1.74 0.74 0 98 0.97 0 .12 2 .12 0.59 0 82 1.19 -0 25 2 89 0 93 1.17 0 96 0.14 2.48 1.35 1.46 1.00 0.34 3 67 0 .96 1.20 1.01 0 09 0 70 1.13 1.31 0.79 -0 .13 1.7 1 1.25 1.44 0.82 0 07 1.85 1.28 1.46 0 82 -0 04 0 73 1.13 1.28 0.93 -0 27 ( contmued on ne x t page)

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APPENDIX 2 (Continued) Table 5. (Continued) Great Bahama Bank-Surface Sediment Samples STATISTICAL DATA Sample# latitude longitude %gravel %sand ss-95 25 27 10 78 42.43 0.15 98.32 ss-96 25 27 .04 78 44.70 0.00 99.10 ss-97 25 27 10 78 46.86 0 03 98 37 ss-98 25 27 .06 78 49 10 0.18 98 26 ss-99 25 27 05 78 51.36 0.04 98 .90 ss-100 25 27.03 78 53 52 0.11 99.44 ss-101 25 27 04 78 55 72 0.21 91.06 ss-102 25 27 02 78 57 89 0.00 98 .61 ss-103 25 26 98 78 58 92 0.00 97.88 ss-104 25 24 .90 79 00.04 0.00 99 .02 ss-105 25 22 90 79 01.00 0 .00 98.42 ss-106 25 21.00 79 01.93 0 .15 99.38 ss-107 25 18 .94 79 02.00 0.34 91.42 ss-108 25 17 .00 79 01.93 0 08 98.15 ss-109 25 14 56 79 02. 03 0 .00 98 .97 ss-110 25 12.02 79 02 02 0.52 99.17 ss-111 25 12 02 78 59.43 0 00 98.97 ss-112 25 11.95 78 57.24 0.21 79 .53 ss-113 25 11.94 78 54. 96 0 .19 78.39 ss-114 25 11.95 78 52 78 0.24 90 64 ss-115 25 11.99 78 50.61 0 29 85.11 ss-116 25 11.97 78 48.36 0.75 79.52 ss-117 25 11.97 78 46 .12 0 .61 76 .19 ss-118 25 12 04 78 43 98 1.91 59.43 ss-119 25 12 03 78 41.83 4 .31 67 67 ss-120 25 11.99 78 39. 52 1.78 82 27 ss-121 25 11.95 78 37. 39 2 84 77.39 ss-122 25 12. 02 78 35 .12 1.17 83.57 ss-123 25 12.02 78 32.98 0.72 88.04 ss-124 25 12 .01 78 30. 70 0.71 72.39 ss-125 25 12 .00 78 28.48 0 24 88.11 ss -126 25 12. 03 78 26.25 0.93 91.53 ss-127 25 12.02 78 24.07 0.43 88 .66 ss-128 25 12.04 78 23.05 1.36 82 .16 ss-129 25 09 98 78 23.06 0 .31 92 .41 ss-130 25 08.03 78 23 09 0 77 88.15 ss-131 25 05 98 78 23 06 0.41 84.58 ss-132 25 03 99 78 23.07 1.59 76. 77 ss-133 25 02 06 78 23 04 0 30 89.25 ss-134 25 00.01 78 23 02 2 24 81.51 ss-135 24 57.97 78 23.03 0 06 96.28 ss-136 24 55.98 78 22 99 0 10 96. 09 ss-137 24 53 99 78 23.04 0 62 81.05 129 %mud median mean st. dev skewness 1.53 1.34 1.50 0 .79 -0. 17 0.90 1.29 1.45 0 73 -0. 22 1.60 1.94 2.18 0.74 -0.41 1.56 1.70 1.99 0.84 -0.39 1.06 1.68 1.93 0 75 -0.43 0.45 1.53 1.74 0 68 -0. 47 8 73 1.74 2 .16 0 92 -0. 16 1.39 1.59 1.93 0.73 0 16 2 .12 1.46 1.70 0 68 -0. 06 0 98 1.85 2 07 0 53 -0. 58 1.58 1.52 1.81 0 63 0 23 0.47 1.43 1.63 0 55 -0. 62 8 24 1.87 2 .13 0 95 -0.54 1.77 0 98 1.34 0 73 0 67 1.03 1.63 1.91 0.69 -0.30 0.31 1.38 1.60 0 .79 -0.55 1.03 1.81 2 08 0.59 -0.23 20.26 1.73 2 .17 0 .83 -0. 10 21.42 1.70 2 .11 0.83 -0.06 9 .12 1.68 2 03 0.72 -0.17 14.60 1.66 2 00 0 75 -0. 26 19.73 1.69 2.04 0 .90 -0.70 23 20 1.74 2 09 0 .92 -0. 63 38 .66 2 .11 2 28 1.21 -1.17 28 .02 2 05 2 .10 1.40 -1.53 1 5.95 1.41 1.56 0 85 -1.40 19.77 1.82 2 02 1.20 -1.38 15.26 1.43 1.74 0.95 -0.39 11.24 1.70 1.95 0.94 -0.63 26.90 1.96 2 24 1.07 -0 .71 11.65 1.73 2.02 0.91 -0.41 7 54 1.61 1.82 0 .99 -0.55 10 .91 1.73 1.99 0.94 -0.56 16.48 1.88 2 10 1.06 -0. 98 7.28 1.64 1.91 0.88 -0.31 11.08 1.70 2 00 1.02 -0.49 15.01 1.72 2 05 0 .94 -0.31 21.64 1.82 2 08 1.12 -0 .96 10.45 1.67 2 03 0 84 -0.06 16.25 1.72 2 04 1.11 -1.2 0 3 66 1.52 1.83 0 .72 0 20 3 .81 1.47 1.77 0 71 0.17 18. 33 1.70 2 05 0 93 0.32 ( contmued on next page)

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APPENDIX 2. (Co n ti nued ) Table 5. (Continued) Great Bahama Bank-Co r e Samp l es STATISTICAL DATA Sample# latitude longitude GBB 1 O.Om 25 10 .23 78 16.17 GBB-1 0.5m GBB1 0.85m GBB-1 I. 10m GBB-1 1 .37m G B B1 1 65m GBB-2 O .Om 25 10.81 78 26 90 G B B-2 0 30m GBB-2 0.60m GBB-2 0.90m GBB-2 20m GBB-2 1.50m GBB 3 0 30m 25 12.53 78 36.17 GBB-3 0.60m GBB-3 1 20 m GBB-3 1.70m GBB-4 0.5m 25 12.98 78 47 22 GBB-4 l.Om GBB-4 1.25m GBB-4 1 75m GBB-5 O O m 25 1 13.11 78 55.44 GBB-5 0 30m GBB-5 0 60 m GBB-5 0 90m GBB-5 1.20m GBB-5 1 .50m GBB-6 O.Om 25 33 10 79 15 82 GBB 6 0.50m GBB-6 l.Om GBB 6 1 5m GBB-6 1 .95 m GBB 7 O.Om 25 33.10 79 15.82 GBB-7 0 5m GBB-7 1 0m GBB-7 1.50m GBB 7 2 .0m GBB 7 2 50m STA 1 O .Om 25 46.95 79 06 09 STA1 0.45m STA-1 0.80m STA-1 1 35 m STA-1 1.70m STA 2 O.Om 25 36 .61 78 56 .91 STA-2 0.35 m STA 3 0 5 m 25 27 0 7 78 48 66 % gravel % sand 0 32 75.78 1.91 66.67 1.74 70 .88 0.89 70 94 1.53 45 34 1.85 15.23 8 34 87 0 5 4.44 86 .07 3 9 1 89 86 2 .22 88.44 11.68 85 82 1 0.45 82.0 7 1.62 87.1 1 0 26 93. 56 1.73 94.05 3.74 93.55 0 56 81.77 1.16 90.29 2 25 81.12 1.31 91.13 0.18 98.64 0.40 91.13 0.09 89 .81 0.09 89 38 2 1 9 93.70 0 .97 96.92 0.21 99 .68 0 32 99 45 0.29 98.83 0 .61 98 79 1.29 98.0 1 0.67 98.9 1 0.39 99.41 0 77 98.89 6 38 93. 0 1 0 92 98 52 0.65 98 77 0 00 99.37 14.78 8 2 95 7 .57 91.39 1 1 67 86 79 4 .91 86 04 0.36 98.92 25.98 72 20 0.47 90.14 130 % m u d median mean st. dev skewness 23.90 2.20 2.35 1.07 -0.7 1 31.42 1.96 2 04 1.32 -0.86 27.38 2 17 2 20 1.36 -0 84 28 .17 2 .15 2.17 1.35 0.66 53.13 1.93 1.93 1.58 -0 .51 82 92 1.80 1.69 1.8 1 -0.61 4 .61 1.54 1.51 1.40 -J.J4 9.49 2.05 2 1 0 1.35 1.44 6.23 1.69 1.85 1.34 -0.70 9 34 1.30 1.70 1.27 0 20 2 50 1.6 3 1.51 1.58 -1.13 7.48 1.63 1.54 1.54 -1.13 11. 27 1.82 2 04 1.01 -1.11 6 18 1.88 2 .13 0 78 -0 53 4.22 1.78 1.9 7 0 .93 1 .33 2.71 1.64 1.74 1.07 -1.46 1 7 67 1.85 2. 1 6 0.94 -0.61 8 55 1.82 2.10 0.96 -1.06 16. 63 1.68 1.92 J.l5 1.00 7.56 1.68 1.95 0.93 -0 92 1.18 1.65 2.01 0 72 -0.12 8.47 1.81 2 .15 0 88 -0.47 10.10 1.88 2.27 1.00 -0.18 10. 53 1.90 2 28 0 85 -0 03 4.11 1.65 1.89 0 93 -1.38 2.11 1.66 1.96 0.8 1 -1.06 0 .11 1.45 1.60 0 70 0.75 0.23 1.59 1.72 0.80 0 75 0.88 1.55 1.71 0.77 -0 68 0 60 1.7 1 1.85 0.83 0 80 0 70 1.51 1.66 0 79 -1.58 0.42 1 .45 1.55 0 95 -0.58 0 20 1.6 1 1.76 0 76 -0. 83 0.34 1.57 1.73 0.80 0 94 0 6 1 1.50 1.48 1.18 -1. 84 0.56 1.5 6 1.72 0 76 -1.33 0.5 8 1.43 1.59 0.74 -0 90 0 .63 1.31 1.59 0 .81 0 06 2 27 0 82 0 77 1.47 -0. 19 1.04 J.l9 1.23 1.27 -0 97 1.54 J.l9 1.15 1.41 1 .29 9 05 1.29 1.38 1.14 1.0 1 0 .72 1.24 1.42 0.82 -0 .11 1.82 0 88 0.49 1.78 -0.44 9.39 1.84 2.14 0 94 -0.44 (continued o n n ext page)

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A PP ENDIX 2. (C ont i nued ) Table 5 (C on ti nu e d ) Great Bahama Ban k Core Sampl es STATISTICAL DA T A Samp le# latitude l ongitude STA-3 l.Om STA 3 1 50m STA-3 2.0m STA-4 O.Om 25 19 97 78 50 .01 STA-4 0 5m STA-4 l.Om STA-4 1.5m STA-4 2 0m STA -19 O.Om 25 05 99 78 34.99 STA-19 0.5m STA-19 0.8m STA-19 1.5m STA-20 .05-.08m 25 02.40 78 36.41 STA-20 .24-.27m STA-20 .44-.47m STA-20 65 68m STA-20 85 88m S T A-20 1.04-1.07 STA-20 1.24-1.2 S T A-20 1.45 -1. 48 STA-20 1.63 1.66 BB2-1 O.Om 24 51.93 79 03 .01 BB2-1 0 25m B B2-1 0.50m BB2-1 !.Om BB2-1 I .35m BB2-2 O.Om 24 40 64 79 02 94 BB2-2 0.5 m BB2 2 !.Om BB2 3 O.lm 24 40.1 0 78 54.30 BB2 -4 0.15m 24 40. 08 78 45. 37 BB2-4 0.5m BB2-4 0 95 m BB2-5 0 30m 24 40. 1 0 78 37 84 BB2 5 0 .7 5m BB2 5 !.20m BB2-7 0.20m 24 49 70 78 31.80 BB27 0.70m BB2-7 .25m BB3-1 0.2m 25 4 3. 99 78 55 00 BB3-1 0.5m BB3-1 .Om BB3-2 0 20 m 25 42.64 78 40.00 BB3-2 0.40m BB3 2 0 60m BB3 -2 0 65m %gravel %sand 2.10 94.65 1.72 92.99 5.14 92 54 0 .81 96.40 0.08 93 .81 0 .32 95.43 4.41 92.27 6 79 9 1 .27 0.33 70 07 0.34 73 97 0.44 87.40 2 67 88 .19 0.43 73.88 0.36 63. 0 5 0.42 63.40 0 .18 81.55 1.36 75.06 0 39 81.55 0 54 83.86 1.14 82 58 3.74 79 00 12 6 1 71. 75 1.25 90 26 5.61 86 20 3 96 88 23 1 1 .26 79 8 1 0.08 87 00 1.16 67 86 8.68 74 5 1 2 .13 63.15 4 07 60.41 0.69 32 22 48 76 26.70 !.54 74 65 4.45 49 7 8 1.90 33.16 0.63 79.64 3.22 68. 7 1 0.97 67.24 0.05 98.83 6 .21 92 20 9 3 1 89. 69 0.06 99.32 !.52 98 26 0.40 99 .19 48 .15 51.29 131 % m ud me d ian mean s t. dev skewness 3.25 1.56 1.74 1.03 -1.01 5.29 1.59 1.75 1.06 -0.77 2 32 1.6 1 1.73 1.16 1 87 2 79 1.69 2 00 0 79 0.59 6.11 1.65 1.98 0.88 -0 29 4.25 1.68 2 0 0 0.76 0.44 3.32 1.68 1.84 1.13 -1.81 1.94 1.63 1.72 1.27 -1.92 29 60 1.96 2.24 1.00 0.56 25 69 1.91 2.23 0 97 0.47 12.16 1.86 2.2 1 0.88 -0.43 9 1 4 1.70 1.90 1.05 -1.31 25 69 1.79 2 14 0.97 -0.43 36. 59 2 1 2 2 37 1.02 -0.65 36.18 2 22 2.42 1. 0 3 -0 .81 18. 27 2 07 2 .37 0 97 -0.41 23.58 1.96 2.28 1.11 -1. 08 1 8 06 1.93 2 29 0 97 -0.37 15. 60 1.93 2.29 0 99 0 .50 16 28 1.75 2.14 1.07 0.62 17. 26 1.75 2.04 1.28 -1.13 15.64 1.08 1.04 1.67 0.21 8 62 1.70 1.87 1.03 0.59 8 1 9 1.68 1.68 1.33 1 .44 7.81 1.62 1.64 1.25 0.97 8 93 1.61 1.43 1.58 1.13 12. 92 1.96 2.21 0 88 0 36 30. 98 2 06 2 2 1 1.10 -0 95 16.81 1.82 1.67 1.61 1 04 34.72 2.18 2 28 1.19 1 .40 35 52 1.92 1.98 1.43 1 25 67 09 2 36 2 26 1.38 -0 .91 24. 54 -2.30 -0 .81 2 .01 1.10 23.81 1.63 1.92 0 96 0.93 45 77 1.58 1.61 1.50 -0.68 64 94 1.79 1.87 1.5 1 -0.73 19.73 1.78 2.11 0.95 -0.45 28 0 7 1.72 1.8 7 1.29 1 .24 31.79 1.69 2 00 1.05 0.55 1.12 1.43 1.61 0 80 -0.20 !.59 1.08 1.15 1.12 1.27 1.00 0 92 0 98 1.25 -1.03 0 62 1.44 1.64 0 .81 0.25 0 22 1.13 1.31 0 89 -0 54 0.41 1.19 1.40 0 .8 4 0 2 1 0 56 -0 69 -0.28 1.96 0 24 (co n tm u ed o n n e x t page)

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APPENDIX 2. (C o ntinue d ) Table 5. (Conti nu e d ) G r eat Bahama Bank Core Samples STATI STICAL DATA Sample# latitude longitude BB3-2 0 80m BB3-2 l.Om BB3-2 1 20m BB3-3 0.2m 25 26 94 78 20. 02 BB3 3 0 7m BB3-3 l.lm BB3 3 1.3m BB3-4 O.lOm 25 27.14 78 37.85 BB3-4 0 27m BB3-4 0.6 0m BB3-4 l.lOm BB3-5 0.50m 25 26. 98 78 58.92 BB3 5 l.Om BB3-5 1 25m BB3 5 l.75m BB3-6 0 20m 25 21.00 79 01.93 BB3-6 0 60 m BB3-6 l.Om BB3 6 1.4m BB3-6 1 8m BB3-6 2 12m BB3-7 0 25m 24 51.98 78 23 .10 BB3-7 0.50m BB3-7 0 75m BB3-8 0.20m 24 52.07 78 37.87 BB3-8 0 60m BB3 8 l.Om BB3-8 1.40m BB3 8 1.70m BB3-9a 0 20m 24 52.10 78 46.9 1 BB3-9a 0.60m BB3 -9a 1.0m BB3-1 0 0.20m 24 51.99 78 56 10 BB31 0 0.60m %gravel % sand 18.48 81.12 16.11 82.95 3 09 96.03 10.8 1 83. 02 22.68 76 .13 17.41 80.44 3.72 93.55 0.46 91.58 8.09 74.38 3 64 93 96 1.65 95.61 0.10 95.46 1.76 93. 76 1.07 93. 37 7 .16 87 04 0.37 97 34 1.01 94.92 2 1 0 91.86 7 .12 89 05 1.30 94 .7 9 30.33 65.93 0 .23 76 .17 3 22 67 .61 7.37 54.52 3 50 74 09 0.23 72.85 1 .40 70 .93 1.36 64 0 7 14 00 46. 1 8 0 19 40 75 7.40 35.30 53.35 1 9 72 0 56 31.59 5 75 51.18 132 % mud median mean st. dev skewness 0.40 0 85 0 70 1.56 -0 .71 0.94 0.56 0.58 1.42 -0 58 0.88 0 80 1.00 0 97 0.70 6.17 0 37 0 63 1.40 0 00 1.19 0.21 0 .31 1.63 -0 .18 2.15 0.88 0.78 1.65 0 60 2.73 1.40 1.47 1.15 -0 77 7. 96 1.48 1.71 0 98 -0.18 17.53 1.24 1.27 1.51 -0.57 2.40 1.24 1.31 1.08 0 83 2 74 1.30 1.42 0 9 7 0 .54 4.44 1.54 1.78 0 67 -0 .34 4.48 1.55 1.75 0.82 1.49 5 56 1.53 1.73 0 80 0 99 5 80 1.52 1.50 1.31 1 .46 2 29 1.33 1.49 0 68 -0.59 4.07 1.4 1 1.60 0 .7 0 -1.12 6 04 1.36 1.47 0 83 -1. 8 1 3 .83 1.36 1.32 1.15 1.76 3 .91 1.43 1.60 0 72 -1.75 3 74 1.26 0 50 1.92 -0 .54 23. 60 1.83 2 1 3 0 93 0.34 29.17 2 03 2 07 1.36 -1.00 38 .11 2.22 1.93 1.77 1.14 22.4 1 1.93 2.04 1.21 1 20 26 92 2.05 2.28 0 .91 0.48 27 67 2.20 2.29 1.09 1.20 34 57 2 .11 2.20 1.16 1. 09 39 82 1.47 1.11 2 05 -0. 56 59 06 2 93 2 84 1.08 -1.60 57 30 2.16 1.62 2.04 -0.72 26 93 2.39 -1.06 2 04 1.38 67 85 2 74 2.66 1.15 1.58 43 07 2 38 2 06 1.74 1.33 (contmued on next page)

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APPENDIX 2 (Continued) Table 5 (Continued) Great Bahama Bank-Control Samples STATISTICAL DATA Sample# latitude longitude % gravel BB2-1 24 51.93 79 03 .01 0 BB2-2 24 40 64 79 02.04 0 54 BB2-3 24 40.10 78 54.30 0.42 BB2 4 24 40.08 78 45 37 0.41 BB2-5 2440.09 78 37.84 0 .18 BB2-6 24 40.04 78 33. 34 5 07 BB2-7 24 49.70 78 31.80 0.15 BB3-1 25 43.99 78 55. 00 0 62 BB3-2 25 42.64 78 40.00 0 .17 BB3-3 25 26 .94 78 20 02 1.08 BB3-4 25 27 14 78 37. 85 0 09 BB3-5 25 26.98 78 58.92 0 BB3-6 25 21.00 79 01.93 0 BB3-7 24 51.98 78 23 10 1.05 BB3-8 24 52.07 78 37.38 0 29 BB3-9 24 52.10 78 46 .91 1.08 BB3-10 24 51.99 78 56 .10 1.66 Great Bahama Bank-Data from Boss (1994) STATISTICAL DATA S ample# latitude longitude %gravel 8516-02 25 33.10 78 46.00 3 80 8516-03 25 23.60 78 35.96 2.90 8516-04 25 25.94 78 33.60 2 .00 8616-15 25 33.56 78 23 .39 10.00 8711-09 25 25 98 78 55 .76 0.40 9108-02 25 43.01 79 07 .83 0 00 9108-03 25 35 34 78 50 62 1.10 9108-05 25 06 72 78 17. 57 0.60 9115-04 25 56.92 79 10 .91 10.10 9115-05 25 58 26 79 09 68 2.30 9115-08 25 53.93 79 02.89 1.50 9115 10 25 46. 02 79 03 37 4 80 9115-12 25 42.54 78 50 66 1.70 9115-20 25 48 .96 78 36.99 3.60 9115-22 25 54.37 78 45 23 12.40 9115-26 25 52.41 78 48.27 2.40 9115-27 25 56.00 78 55.31 2.90 % sand 98.42 84.83 74.47 83.83 82 16 71.55 88.49 98.49 98 77 93.04 96 .19 97 88 99 37 88 06 91.98 50.27 40.14 % sand 79.10 64.40 95 80 79. 60 78 50 98 80 97.40 86 00 88 50 95 70 95.00 90.50 96. 00 94.70 75. 20 95. 70 96 90 133 % mud median mean st. dev skewness 1.58 1.86 2. 07 0 7 -0.48 14. 63 1.68 1.91 0 94 -0. 43 25 .11 2.01 2.2 1.05 -0.74 15.76 1.75 2.03 0 95 -0.44 17.66 1.99 2.24 0 87 -0.43 23.38 1.09 1.23 1.28 -0.33 11.36 1.71 2.06 0 84 -0.03 0 89 1.24 1.41 0 77 -0 35 1.06 1.36 1.55 0 85 -0.23 5 88 0 69 1.03 1.06 0.31 3.72 1.45 1.69 0 88 -0.05 2 .12 1.53 1.81 0 .61 0.37 0 63 1.36 1.54 0.55 -0 5 10.89 1.68 2 .01 0 .91 -0 5 7 73 2. 12 2 .31 0 84 -0 66 48.65 2.39 2 35 1.28 1.01 58.2 2.23 2.17 1.45 0 9 %mud median mean st. dev skewness 17.10 ND 2.85 1.67 -0 59 32 .70 ND 3 28 1.77 -0 82 2.20 ND 1.26 1.21 0 56 10.40 ND 2 .13 1.91 -0 42 21.10 ND 2 96 1.42 0.30 1.20 ND 1.55 0.86 1.04 1.50 ND 1.60 1.12 0 22 13.40 ND 2.36 1.46 0 64 1.40 ND 1.13 1.42 -0 30 2.00 ND 1.12 1.10 0.81 3.50 ND 1.42 1.26 0 82 4 70 ND 1.19 1.42 0.73 2.30 ND 1.45 1.19 0 36 1.70 ND 1.31 1.21 0.16 12.40 ND 1.65 2.17 -0 09 1.90 ND 1.31 1.18 0 29 0.20 ND 1.47 1.19 -0.73

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134 APPENDIX 3. POINT COUNT DATA FOR SURFACE AND CORE SAMPLES The following several pages represent point count data for all samples taken, surface and core Each page consists of20 samples, of which one hundred grains were counted per section. Methods of point counting are described in the methods section.

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Grea t Ba h ama B ank-S u r fa ce Sediment S a mpl es Sam ple# s s1 ss-2 ss3 ss-4 ss 5 ss-6 Pelle t s 30 23 32 32 42 45 O oi d s 1 0 2 0 0 I 0 M ic.Grai n s 25 26 22 27 13 1 7 G r a pest o n e 0 0 I 0 0 0 Hali m eda 23 32 3 1 22 29 25 Foram I 5 I 6 4 3 B ivalve 1 0 9 1 0 9 9 7 Gas tr o pod I 3 3 0 0 3 Echinoid 0 0 0 3 0 0 Cor a l 0 0 0 0 0 0 B ryozoa n 0 0 0 0 0 0 Lithic F r ag ment s 0 0 0 0 0 0 Uni d e n tified 0 0 0 I 2 0 Tota l 1 00 100 1 00 100 100 100 Sample# ss-1 1 ss1 2 ss1 3 ss 14 ss1 5 ss-16 Pellets 4 7 42 30 49 52 55 Ooids 0 0 0 0 0 2 M ic.Grains 2 4 35 4 6 27 23 20 Grapestone 0 I 0 0 0 2 Ha l imeda 20 1 6 1 3 13 8 7 Fo r a m 2 I I 2 5 7 B iva l ve 6 5 9 8 8 5 Gastropod 0 0 I 0 4 0 Ec h i n oi d 0 0 0 0 0 2 Cora l 0 0 0 0 0 0 B ryozoan 0 0 0 0 0 0 Lithic Fr agments 0 0 0 0 0 0 Uni dent ifie d I 0 0 I 0 0 Tota l 100 100 '--JOO_ 100 1 00 Tabl e 6. Po i n t c o un t d a t a for all s u face and core se dim e nt s ampl es. ss 7 3 4 2 32 0 1 7 3 1 0 2 0 0 0 0 0 100 ss-17 55 0 29 0 5 2 9 0 0 0 0 0 0 1 00 ss 8 ss 9 ss -10 25 29 38 I I 0 24 27 21 0 0 0 23 2 6 25 15 2 2 8 II 9 2 I 2 2 0 0 0 0 0 0 0 0 0 0 0 0 3 3 1 0 0 100 100 s s1 8 ss1 9 ss-20 4 7 51 6 1 0 0 0 25 37 22 0 I 0 8 0 2 3 5 8 1 5 5 7 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 I I 0 100 1 00 100 (conti nued on ne xt page) I z t=' w -Ci 0 = -e r = (t) .e -w V\

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Great Bahama Bank-Surface Sediment Samples Sample# ss-21 ss-22 ss-23 ss-24 ss25 Pellets 60 57 64 45 50 Ooids 6 I 0 2 I Mic Grains 24 17 20 30 25 Grapestone 2 I 0 0 0 Halimeda 4 16 8 4 6 Foram I 2 3 10 10 Bivalve 3 6 5 6 3 Gastropod 0 0 0 2 0 Echinoid 0 0 0 0 0 Coral 0 0 0 0 2 Bryozoan 0 0 0 0 I Lithic Fragments 0 0 0 0 0 Unidentified 0 0 0 I 2 Total 100 100 100 100 100 Sample# ss-31 ss-32 ss-33 ss-34 ss-35 Pellets 42 41 54 29 31 Ooids 0 0 I 0 0 Mic.Grains 30 30 11 27 15 Grapesto n e 0 0 0 2 0 Halimeda 6 11 17 26 44 Foram 8 6 5 4 4 Bivalve 13 12 10 11 3 Gastropod I 0 I 0 I Echinoid 0 0 0 0 0 Cora l 0 0 0 0 0 Bryozoan 0 0 0 0 0 Lithic Fragments 0 0 0 0 0 Unidentified 0 0 I I 2 Total 100 100 100 100 100 ss-26 ss-27 47 41 0 0 29 26 0 0 7 10 13 12 I 7 3 2 0 0 0 0 0 0 0 0 0 2 100 100 ss-36 ss-37 19 37 2 0 19 17 0 0 48 39 5 3 5 3 2 I 0 0 0 0 0 0 0 0 0 0 100 100 ss-28 ss29 ss-30 37 36 42 0 0 0 32 35 31 0 0 I 11 10 I 16 9 9 3 10 11 0 0 I 0 0 0 0 0 I 0 0 I 0 0 0 I 0 2 100 100 100 ss-38 ss-39 ss-40 38 52 51 I 0 0 8 12 5 8 I 3 28 31 34 I I 2 1 3 3 5 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 100 100 (continued on next page) OOIZ = w .... e:r= (1 ('D 0 .._... .... Ei' = ('D -e ...... w 0\

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Great B ahama Bank-Surface Sed im e n t Samples Samp le# ss-41 ss-42 ss-43 ss-44 ss-45 Pellets 58 47 58 40 66 Ooids 0 5 0 2 0 Mic.Grains 8 II 1 7 I I 15 Grapestone 9 5 II 14 6 H alimeda 8 14 7 8 4 Foram 4 3 2 7 3 B iva l ve 13 12 5 12 3 Gastropo d 0 3 0 5 I Echinoid 0 0 0 0 0 Coral 0 0 0 0 0 Bryozoan 0 0 0 0 0 Lithic Fragments 0 0 0 0 0 Uni d en tified 0 0 0 I 2 Tota l 1 00 100 100 100 100 Sample # ss-51 ss 52 ss-53 ss-54 ss-55 Pellet s 62 67 60 52 68 Ooids 5 0 4 36 I M ic Grains 14 12 14 8 10 Grapes t one 6 12 10 2 0 Halimeda 6 I 2 0 3 Foram I 3 0 0 6 Biva l ve 6 4 10 2 6 G astro pod 0 I 0 0 2 Echinoid 0 0 0 0 0 Cora l 0 0 0 0 0 Bryozoan 0 0 0 0 0 Lithi c Fragments 0 0 0 0 2 Unidentified 0 0 0 0 2 Total 1 00 1 00 100 100 100 ss-46 ss-47 36 49 0 I 24 22 6 4 1 3 II 1 0 2 9 9 0 I 0 0 0 0 0 0 0 0 2 I 100 100 ss -5 6 ss 57 5 6 53 7 0 1 2 1 6 II 9 2 9 2 5 8 5 0 2 0 0 0 0 0 I 0 0 2 0 100 1 00 ss -4 8 ss-49 ss5 0 60 53 6 1 4 0 II 13 1 2 17 0 7 3 3 16 3 8 3 I 5 5 3 4 2 I 0 I 0 0 0 0 2 I 0 0 0 0 I 0 0 10 0 1 00 100 ss 58 ss-59 ss -6 0 52 51 49 4 0 6 II 19 1 8 1 7 10 19 I 9 I I 3 4 10 8 I 2 0 2 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 100 100 100 (continued on next page) J I I C"'"C ;'t;rj 0 = w e;,.-... c: (] ttl 0 c.= .._, s = ttl Q. .._, ....... VJ -....]

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Great Bahama B a n k Surface Sed i ment Samples Samp le# ss 6 1 ss-62 ss 63 ss 64 ss-65 Pelle t s 47 48 47 42 56 Oo i ds I I I 7 I Mic.G r a i ns 12 14 1 5 10 1 2 Grapestone 1 4 14 26 27 7 H a l imeda 19 4 4 2 14 Fo r am I I I 5 6 B i va l ve 6 1 5 5 5 3 Gas tr o p od 0 2 I 0 I Ec h i n o i d 0 0 0 0 0 Cora l 0 0 0 0 0 Bryozoa n 0 0 0 0 0 L i t h ic F r ag m e nt s 0 0 0 2 0 Un i de n tified 0 I 0 0 0 Tota l 1 00 1 00 100 1 00 100 Sam ple# ss-7 1 ss-72 ss 73 ss-7 4 ss-75 Pellets 1 9 15 1 7 19 7 Ooids 0 0 0 0 0 Mic.G r ains 25 1 6 32 2 1 1 7 Grapes t one 6 5 5 7 2 Ha l imeda 42 32 28 40 54 Foram 2 1 0 I 5 5 B i valve 6 14 16 7 14 Gas tr opod 0 4 0 0 0 Ec h inoid 0 0 0 0 0 Cora l 0 0 0 0 0 Bryozoa n 0 0 0 0 0 Lit hic Fragme n ts 0 2 0 0 0 Uniden t ifie d 0 2 I I I Tot a l 100 1 00 1 00 100 1 00 ss-66 ss 67 34 33 0 0 2 1 23 27 26 7 9 4 2 .s. 5 0 I 0 0 0 0 0 I 2 0 0 0 100 1 00 ss-76 ss-77 5 6 0 0 32 33 4 II 33 26 II I 14 22 0 0 0 0 0 0 0 0 0 0 I I 100 100 ss 68 ss-69 35 1 0 I 0 2 1 3 8 7 9 24 18 2 4 10 1 8 0 2 0 0 0 0 0 0 0 0 0 I 100 100 ss-78 ss 79 1 0 1 4 0 0 37 15 5 0 22 59 5 3 19 8 I 0 0 0 0 0 0 0 0 0 I I 100 1 00 (conti n ued o n nex t page) ss 70 15 0 28 1 0 1 9 7 1 9 I 0 0 0 0 I 100 ss-80 36 0 22 2 34 2 4 0 0 0 0 0 0 1 00 I I I ('I) C'\Z 0 = w .... =-= (') ('I) 0 c.= --.... = = ('I) ,e ....... V..l 00

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G r eat Bah a m a Bank Surface Se d ime n t Samp l es Sam ple# ss-81 ss-82 ss-83 ss-84 ss85 P ellets 37 40 22 23 20 Oo i d s 0 0 0 0 2 M i c G r a in s 14 20 1 5 28 1 3 G r a p es to n e 2 7 23 48 36 52 Ha l i meda 1 3 2 2 II I Fora m 3 1 0 6 0 2 Biva l ve 3 5 4 2 5 Gas tr opo d 0 0 I 0 I Echinoi d 0 0 0 0 0 Coral 0 0 0 0 0 Bryo z o an 2 0 0 0 0 Lit h ic Fragments 0 0 0 0 0 Unident i fied I 0 2 0 4 Tota l 1 00 1 00 100 1 00 100 Sampj e # ss-9 1 ss-92 ss-93 ss-94 ss 9 5 Pelle t s 48 4 0 45 37 39 Oo i ds 0 I 0 0 I Mic G r a in s 10 1 6 3 0 2 1 1 5 G r a p es t o n e 29 26 1 3 25 2 8 H a l i m eda 8 3 6 13 7 Fo r a m 2 4 2 0 2 Bivalve 2 7 4 3 7 Gastropo d I I 0 I 0 Echino i d 0 I 0 0 0 Co r al 0 0 0 0 0 Bryo z oan 0 0 0 0 0 Lithic Frag m e n ts 0 0 0 0 0 U n ide nt ified 0 I 0 0 I Tota l 1 00 100 1 00 1 00 100 ss-86 ss-87 28 22 0 I 13 14 40 52 II 2 2 3 5 6 0 0 0 0 0 0 0 0 0 0 I 0 10 0 100 ss 96 ss-97 4 9 57 0 0 I I 2 4 36 6 0 6 0 2 I 4 3 I 0 0 0 0 0 0 0 0 0 0 1 00 1 00 ss-88 ss-89 3 0 42 2 0 1 6 13 44 3 1 3 6 2 4 I 2 I I 0 0 0 0 0 0 0 0 I I 1 00 100 ss-98 ss 99 66 60 0 2 1 6 1 3 6 9 4 7 6 2 I 2 0 3 0 0 0 0 0 0 0 2 I 0 1 00 1 00 (co ntinu ed o n n e x t p age) ss-90 2 4 0 26 38 2 I 5 4 0 0 0 0 0 1 00 ss-100 5 9 7 1 6 1 6 I I 0 0 0 0 0 0 0 1 00 0"'1-0 ti'l:'j = w ::t. == (") 0 Q.= '-'::t. = = s -w \0

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G r eat Ba h ama Ban k S u rface Sed i m e nt Sam pl es Sam ple# ss 10 1 ss-1 02 ss1 03 ss1 0 4 ss-10 5 Pell e t s 62 56 81 82 7 1 Oo i ds 2 0 0 I 2 Mic G r ains 22 27 9 9 1 6 G rap es t o n e 0 2 5 4 0 Hal i m eda 2 2 3 2 4 Fora m 2 6 0 0 2 Biva l ve 1 0 5 2 2 4 Gastro pod 0 2 0 0 0 Ec h ino i d 0 0 0 0 0 Co r a l 0 0 0 0 0 B ryozoan 0 0 0 0 0 Li th ic F r agments 0 0 0 0 0 Uni d en ti fied 0 0 0 0 I T otal 1 0 0 100 1 00 1 00 1 0 0 S a mple# ss-111 ss-112 ss-113 ss-114 ss 1 1 5 Pelle t s 60 56 57 66 69 Ooids 1 8 2 4 0 I Mic G r ai n s 1 2 20 18 20 21 G r a p es t o n e I 0 0 0 0 Ha lim eda 4 10 II 4 6 Fo r am 0 6 5 2 I Biva l ve 4 6 4 6 2 Gas tr opo d I 0 0 0 0 Ec hin oi d 0 0 I 0 0 Co r a l 0 0 0 0 0 B ryozoa n 0 0 0 0 0 Lit h i c Fragme nt s 0 0 0 0 0 Unide n tified 0 0 0 2 0 Tot a l 100 1 00 1 00 1 00 1 00 ss-106 ss 107 8 4 38 4 0 5 3 9 I I 5 11 0 3 I 6 0 0 0 0 0 0 0 I 0 0 0 I 100 100 ss-116 ss1 17 4 4 44 0 0 32 3 4 2 I 11 1 6 4 3 5 2 0 0 0 0 0 0 0 0 0 0 2 0 100 1 00 -ss -10 8 ss-1 09 58 63 4 4 28 2 1 0 2 3 0 0 2 6 8 0 0 0 0 0 0 0 0 0 0 I 0 1 00 10 0 ss-118 ss-119 5 0 49 0 2 28 22 I 6 14 2 3 6 4 9 0 0 0 0 0 I 0 0 0 0 0 3 1 00 100 (co ntinued o n n ext page) ss -110 70 3 11 6 4 0 5 0 0 0 0 0 I 1 00 ss1 20 48 2 27 5 7 2 9 0 0 0 0 0 0 1 00 c::r"'C C'\Z 0 ::< = w ...... er= (j t!l 0 c::l.= ..... = = t!l c::l. -...... 0

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Great Baham a Ba n k-Surface Se d iment Samples Sam ple# ss -121 ss1 22 ss1 23 ss-124 Pellets 57 52 57 41 Oo i ds 0 0 0 0 Mic G r ains 19 26 20 36 Gra p es t one 4 2 I 2 H a l i m e d a 13 6 1 5 5 Foram 4 4 3 5 Bivalve I 8 2 7 Gastropo d 0 0 0 2 Ec h inoid 0 I 0 0 Coral 0 0 0 0 B ryozoan 0 0 0 0 Li t hic Fragments 0 I 0 0 Unidentified 2 0 2 2 Tota l 100 100 1 00 1 00 Samp le# ss-131 ss132 ss-133 ss1 3 4 Pellets 60 5 1 55 56 Ooids 0 0 0 I Mic Grai n s 2 5 28 1 9 25 Gra p estone 2 0 2 0 Ha l i m eda I 5 6 1 3 Fo r am 4 4 6 2 Biva l ve 5 8 I I 2 Gastropod 3 I 0 I Ech i n oid 0 0 0 0 Cora l 0 0 0 0 Bryozoa n 0 0 0 0 Lithic F r agments 0 0 0 0 U n identified 0 3 I 0 Tota l 100 1 00 1 00 100 ss-125 ss126 ss1 27 5 5 61 57 0 0 0 28 1 7 29 I 3 0 9 3 6 4 8 7 2 I I 0 5 0 0 0 0 0 0 0 0 I 0 0 0 0 I I 0 1 00 1 00 1 00 ss1 35 ss1 36 ss1 37 72 66 53 0 0 0 20 2 1 29 2 0 0 3 7 3 0 I 8 2 3 6 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 I I I 100 100 1 00 (c on t inued o n next p a g e ) ss-128 ss1 29 54 56 0 0 21 30 4 0 1 0 6 5 6 3 2 3 0 0 0 0 0 0 0 0 0 0 0 1 00 1 00 ss-130 68 0 13 2 5 7 3 0 0 0 0 0 2 1 00 C"loO o...z = w ..... .... =-= (j n> 0 Q.= '-' ..... 5i' = n> -e ........ .J:>. ........

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Great Bahama Bank-Core Sediment Samples Sample# GBB-1 O.Om GBB-1 0.5m GBB-1 0.85m GBB-1 I.IOm GBB-1 1.37m Pellets 48 54 41 41 31 Ooid s 0 0 0 0 0 Mic.Grain s 30 20 24 16 22 Grapestone 0 0 0 0 0 Halim eda 6 7 6 5 4 Foram 5 II 16 27 24 Bivalve 10 7 II 8 15 Gastropod 0 0 I 0 2 Echinoid 0 0 0 0 0 Coral 0 0 0 0 0 Bryo zoa n 0 0 0 0 0 Lithic Fragments 0 0 0 I 0 Unidentified I I I 2 2 Tot a l 1 00 100 100 100 Sample# GBB-21 20 m GBB-2 1 50m GBB-3 0.30m GBB-3 0.60m GBB-3 1.20m Pellet s 50 62 66 67 58 Ooids 0 0 3 0 0 Mic.Grains 1 8 17 1 7 18 1 6 Grapestone 6 0 0 5 4 Halimeda 4 8 2 I 8 For a m 2 I 8 4 3 Biva lve 5 5 3 3 3 Gastropod 0 0 I 2 0 Echinoid 0 0 0 0 0 Cora l 0 0 0 0 0 Bryozoan 0 0 0 0 0 Lithic Fragments 14 7 0 0 8 Unide ntifi ed I 0 0 0 0 T otal 100 1 00 100 100 100 GBB1 1.65m GBB2 O.Om GBB-2 0.30m 7 66 44 0 0 2 19 16 33 0 I 0 4 I 8 17 5 I 37 4 0 7 0 0 0 0 0 0 0 0 0 0 0 7 7 II 2 0 I 100 100 100 GBB-31.70m GBB-4 0.5m GBB-4 1 0m 6 8 62 67 0 0 0 II 19 1 9 7 0 0 4 0 8 0 8 2 1 0 6 3 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 0 2 I 100 100 100 GBB-2 0.60m GBB-2 0 .90m 29 50 0 0 38 27 0 0 10 9 6 5 6 7 0 0 0 0 0 0 0 0 9 I 2 I 100 100 GBB-41 25m GBB-41.75m 58 76 I 0 20 1 2 I 0 9 I I I 9 9 0 I 0 0 0 0 0 0 0 0 I 0 100 100 ( continu e d o n next page) 0''"= Q\Z 0 >< = w ..... .... == ('D 0 c.= ..._ .... sr = ('D ,e -N

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Great Bahama Bank-Core Sediment Samples Sample# GBB-SO .Om GBB-5 0.30m GBB-50. 60m GBB-50. 90m GBB-51.20m Pellets 75 66 52 59 70 Ooids 0 0 I 0 0 Mic.Grains 1 5 20 20 30 17 Grapestone 0 0 0 0 0 Halimeda 2 3 3 4 2 Foram 2 4 4 2 2 Bivalve 5 7 6 4 8 Gastropod 0 0 3 0 0 Echinoid 0 0 0 0 0 Coral 0 0 0 0 0 Bryozoan 0 0 0 0 I Lithic Fragments 0 0 11 0 0 Unidentified I 0 0 I 0 Total 100 100 100 100 100 ----Sa mple # GBB-61 95m GBB-70. 0m GBB-7 O .Sm GBB-71.0m GBB-71.50m Pellets 39 37 55 44 42 Ooids 0 6 I 7 3 Mic.Grains 16 15 12 15 11 Grapestone 4 I I I 3 Halimeda 24 20 20 21 23 Forarn 2 8 3 3 3 Bivalve 13 12 5 9 12 Gastropod I 0 0 0 0 Ech in oid 0 0 0 0 0 Cora l 0 0 3 0 0 Bryozoan 0 0 0 0 0 Lithic Fragments 0 0 0 0 2 Unidentified I I 0 0 I Total 100 100 100 100 100 GBB-51 50m GBB-60. 0m GBB-60.50m 70 37 45 0 2 4 18 II 19 0 3 2 2 32 1 8 0 3 4 6 12 5 3 0 2 I 0 0 0 0 0 0 0 0 0 0 0 0 0 I 100 100 100 GBB7 2 0m GBB-7 2.50m STA-1 O .Om 33 35 64 3 2 6 16 15 12 4 I 9 25 26 I 3 2 0 II 7 3 I 2 0 0 0 0 0 I 0 0 0 0 4 9 4 0 0 I 100 100 100 GBB-6 1.0m GBB-61 5m 54 45 5 3 16 8 I 0 15 28 5 8 3 8 0 0 0 0 0 0 0 0 0 0 I 0 100 100 STA-1 0.45m STA-1 0 80m 53 54 3 2 10 16 6 5 12 8 3 3 9 7 I 0 0 0 0 0 0 0 0 4 3 I 100 100 (continued on next pa g e) I I 1-3> ""= r:J'""= ;"trj 0 = ..,. sr= (j t'D 0 .._., ..,. e; = t'D .._., ....... w

PAGE 155

Grea t Bah a ma B a n k Co re S edim ent Sampl es Sampl e # S T A-11.3 5 m S T A-11. 70m S T A 2 O O m S T A 2 0 35m STA3 0 .5 m Pell e ts 78 57 50 56 6 1 Ooids 6 3 0 0 0 Mic Grains 9 II 1 7 1 3 14 G r apes t o n e 2 8 9 2 2 H a l ime d a 0 3 9 6 2 F o r a m 0 I 0 0 8 B ival ve I 7 6 6 4 Gas tr o pod I 0 0 0 2 Ec h i n o i d 0 0 0 0 0 Co r a l 0 0 0 0 0 Bry o zoa n 0 0 0 0 0 Lith ic Fragm e nts 3 9 8 1 7 5 U n ide nt ifie d 0 I I 0 2 T ota l 100 100 100 100 100 Samp le# S T A-4 1.0m S T A-4 1 .5 m STA-42. 0 m ST A-1 9 O.Om ST A 1 9 0.5 m Pelle t s 69 72 85 66 67 Ooids I I 0 0 0 Mic.Grains 7 1 2 7 1 5 12 G r apestone 0 3 I 0 0 H a l i meda 7 6 3 8 6 Fora m I 3 0 5 3 Bi va lve 6 3 3 4 I I Gastropod 2 0 0 0 0 Ec hin o id 0 0 0 0 0 Cora l 0 0 0 0 0 B ryozoa n 0 0 0 0 0 Li t hi c Frag m ents 5 0 I 0 0 U nid entifie d 2 0 0 2 I T o ta l 1 00 1 00 1 00 1 00 1 00 -STA-31.0 m STA-31.50m STA-32.0m 7 0 72 8 3 0 0 0 5 4 I I 2 2 3 8 5 0 2 2 I 5 4 I I 7 0 0 0 0 0 0 0 0 0 0 6 4 I I 0 0 100 100 1 00 ST A-19 o.am STA-19 1.5m S T A-20 .05 m 72 64 5 0 I 0 0 I I 13 2 5 0 0 I 0 0 5 7 4 9 8 19 6 0 0 2 0 0 0 0 0 0 I 0 0 0 0 2 0 0 0 1 00 1 00 100 S TA-4 O O m STA-4 0 5 m 8 1 68 I I 8 15 3 0 I I 2 2 2 5 0 4 0 0 0 0 0 0 I 4 I 0 1 00 100 STA-20 24m S TA20 .4 4 m 6 1 47 0 0 27 31 0 0 I 10 6 8 5 2 0 0 0 0 0 0 0 0 0 0 0 2 100 100 (conti nu e d o n n ext p age) ('!) 0\Z ,;..._'=' Q ;;< = w = = (;) ('!) Q ._., -.... = = ('!) ,e ......

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Great Bah ama Bank-Core Sediment Sam ple s Sa mple # STA-20 65m STA -2 0 .85m STA-20 1.04m S TA -20 1 24m STA-20 1.45m Pellets 69 66 68 59 67 Ooids 0 0 0 0 0 Mic.Grains 1 9 19 17 18 23 Grapesto ne 0 0 0 0 0 Halimed a 3 2 5 1 2 2 Foram 3 7 6 6 2 Bivalve 5 6 4 3 6 Gas tr opod 0 0 0 0 0 Echinoi d 0 0 0 0 0 Co r a l 0 0 0 0 0 Bryozoan 0 0 0 0 0 Lithic Fra g m e nt s 0 0 0 0 0 U nidentifi e d I 0 0 2 0 T ota l 100 100 100 1 00 100 Samp le # 8821 1 35m 882-2 O .Om 882-2 0 5m 882-2 1 0m 882-3 0.1m Pellets 51 47 42 34 47 Ooids I 0 0 0 0 Mic.Grains 16 18 23 13 14 Gra pestone 0 0 0 0 0 Halimeda 23 21 23 36 27 For am 2 3 6 4 2 Bivalve 7 9 6 10 7 Gastropod 0 I 0 3 3 Echinoid 0 0 0 0 0 Co r a l 0 0 0 0 0 Bryozoan 0 0 0 0 0 Lithic Fragments 0 0 0 0 0 Unidentified 0 I 0 0 0 Total 100 100 100 1 00 100 STA 20 1 63m 882-1 O.Om 68 30 0 0 22 1 8 0 0 3 44 5 4 ,2 2 0 I 0 0 0 0 0 0 0 I 0 0 100 100 882-4 0 15 m 882-4 0.5m 50 27 I 0 15 34 0 0 1 7 17 2 15 1 3 6 2 I 0 0 0 0 0 0 0 0 0 0 100 100 882-1 0 25m 882 1 0.50m 882 11.0m 39 58 53 0 0 0 1 0 13 1 0 0 0 0 35 19 23 4 2 3 1 2 8 10 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 100 100 100 --882-4 0 95m 882-5 0.30m 882-5 0. 75m 6 64 37 0 0 0 18 II 1 5 0 0 0 0 16 12 I 3 13 2 6 II 0 0 0 0 0 0 0 0 0 0 0 0 73 0 12 0 0 0 1 00 100 100 (con t inued on next pa ge) ;...._t:::' (j"""' 0 = w ..... e:r= (j 0 Q.= _. ..... sr = Q. -..j::o. Vl

PAGE 157

Great Bahama Bank-Core Sediment Samples Sample# 662-51. 20m 662-7 0 20m 6627 0 70m 662-7 1 25m 663-1 0.2m Pellet s 29 78 65 51 54 Ooids 0 0 0 0 0 Mic.Grains 17 13 14 18 15 Grapestone 0 0 0 0 15 Halimeda 16 2 5 16 0 Foram 14 I 8 7 2 Biva lve 14 4 6 4 6 Gastropod 2 0 I 4 0 Echinoid 0 0 0 0 0 Cora l 0 0 0 0 0 Bryozoan 0 0 0 0 0 Lithic Fragments 5 0 0 0 8 Unidentified 3 2 I 0 0 Tota l 100 100 100 100 100 Sample# 663-2 0 65m 663-20.80m 663-21.0m 663-2 1 20m 663-30.2m Pellets 39 43 47 39 35 Ooids 0 I 0 0 0 Mic.Grain s II 1 2 1 8 II 16 Grapestone 6 6 2 9 4 Halimeda II 4 2 5 6 Foram I 3 2 2 8 Bivalve 14 4 2 4 2 Gastropod 0 0 3 0 0 Echinoid 0 0 0 0 0 Cora l 0 0 0 0 0 Bryozoan 0 0 0 0 0 Lithic Fragments 18 27 24 30 28 Unidentified 0 0 0 0 I Total 100 100 100 100 100 663-1 O .Sm 663-11. 0m 663-2 0 20m 59 52 51 0 0 0 12 10 12 II 9 1 2 5 6 8 0 I 0 6 7 7 0 I 0 0 0 0 0 0 0 0 0 0 7 14 10 0 0 0 100 100 100 663-3 0 7m 663-3 1.1m 663-31. 3m 36 39 35 0 I 2 6 8 9 II II 7 2 3 13 6 5 2 5 3 3 0 I 2 0 0 0 0 0 0 0 0 0 34 29 27 0 0 0 100 100 1 00 663-2 0.40m 663-2 0 60m 51 44 I 0 16 1 8 9 5 5 13 0 6 4 4 0 0 0 0 0 0 0 0 12 10 2 0 100 100 663-4 0 10m 663-4 0 27m 53 47 I 0 1 6 14 9 5 I 9 5 8 6 4 0 I 0 0 0 0 0 0 9 12 0 0 1 00 100 (continued on next page ) I I '='""t' 0\Z = --er--= 0 --..... = = ,e ...... 0\

PAGE 158

Great Bahama Bank-Core Sediment Samples Sample# BB3-4 0.60m BB3-41 10m BB3 -5 0.50m BB3-51 0m BB3-51 .25m Pellets 64 61 71 81 70 Ooids 0 0 0 0 2 Mic.Grains 8 9 6 4 8 Grapestone 4 9 2 2 2 Halimeda 7 5 I 5 3 Foram I 2 3 0 I Biva lve 2 3 3 3 5 Gastropod 2 0 2 I I Echinoid 0 0 0 0 0 Coral 0 0 0 0 0 Bryozoan 0 0 0 0 0 Lithic F r agments 12 II 12 4 7 Unide ntifi ed 0 0 0 0 I Total 100 100 100 100 100 Sample# BB3-6 1 8m BB3-6 2 12m BB3-7 0.25m BB3-7 0.50m BB3-7 0 75m Pellets 78 60 70 58 62 Ooids 2 3 0 0 0 Mic .G rain s 6 7 1 3 24 15 Grapestone 2 0 I 0 0 H a l imeda 6 2 2 3 4 Foram 0 0 5 4 6 Biva l ve 6 I 9 4 II Gastropod 0 0 0 0 2 Echinoid 0 0 0 0 0 Coral 0 0 0 0 0 Bryozoan 0 0 0 0 0 L ithi c Fragments 0 27 0 7 0 Unide ntifi ed 0 0 0 0 0 Total 100 100 100 100 100 -BB3 -5 1 75m BB3-6 0.20m BB3 -6 0 60m BB3-6 1.0m 75 79 78 83 0 8 4 6 5 7 7 6 0 I 3 3 3 I 2 0 3 I I 0 7 2 4 2 I I I 0 0 0 0 0 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 100 100 100 100_ BB3 -8 0 20m BB3-8 0.60m BB3-81 0m BB3-81.40m 64 72 57 56 0 0 0 0 14 16 14 14 0 0 0 0 3 5 1 2 I I 3 3 4 8 5 4 2 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 II 0 II 2 0 0 0 0 100 100 100 100 (co ntinued on next page) BB3-6 1 4m 80 I 3 3 3 0 6 0 0 0 0 4 0 100 BB3-81.70m 4 7 0 24 0 3 5 19 I 0 0 0 I 0 100 t;'t'-'j 0'\Z (j)ooooC 0 :>< = w -. c:r-. = (] I'D 0 c.= ---e:r = I'D 5 --.._)

PAGE 159

Grea t B a ham a Bank-Co re Sedimen t Samp l es Sam ple# 663-9a 0 .20m 663-9a 0 60m Pellets 58 39 Ooids 0 0 M i c G r ains 32 35 Grape s tone 0 0 H a l i med a 2 4 Fo r am 5 9 B ival v e 3 3 Gastropod 0 0 Ec h i n oid 0 0 Coral 0 0 Bryozoan 0 0 Lit hi c F r agme nt 0 10 U n ide nt ified 0 0 Total 1 00 100 6 63-9a 1 0 m 663 0 .20m 7 54 0 0 1 2 28 0 0 7 6 4 6 5 4 0 0 0 0 0 0 0 0 6 5 2 0 0 10 0 1 00 (co n t i nued on next page) 663-10 0 60 m 50 0 28 0 7 1 0 5 0 0 0 0 0 0 100 S!:""d ;...._!:::' 0 :>< = w .... = = (j 0 Q.= .... ..... = = .e -00

PAGE 160

Great Bahama Bank-Surface Sediment Samples Sa mple# BB2-1 BB2-2 BB2-3 BB2-4 P e llets 75 52 57 68 Ooids 0 0 0 0 Mic.Grains 6 17 24 14 Grapestone 0 0 0 0 Halimeda 12 19 9 7 Foram 2 3 2 4 Bivalve 5 9 8 6 Gastropod 0 0 0 0 Echinoid 0 0 0 0 Coral 0 0 0 0 Bryozoan 0 0 0 0 Lithic Fragments 0 0 0 0 U n identified 0 0 0 I Tota l 100 100 100 100 Sample# BB3-4 BB3-5 BB36 883-7 Pellet s 56 87 80 67 Ooids 0 0 6 0 Mic.Grains 1 9 I 4 24 Grapestone 3 2 2 0 Halimeda II 4 0 I Foram 3 0 2 3 Bivalve 2 4 3 5 Gastropod 0 I I 0 Echinoid 0 0 0 0 Cora l 0 0 0 0 Bryozoan 0 0 0 0 Lithic Fragments 6 I 2 0 Unidentified 0 0 0 0 Total 100 100 100 100 BB2-5 BB2-6 BB2-7 68 46 79 0 0 0 14 13 II I 2 0 5 6 4 4 9 I 7 19 5 I 0 0 0 0 0 0 0 0 0 0 0 0 4 0 0 I 0 100 100 100 883-8 883-9 883-10 70 46 41 0 0 0 14 30 25 0 0 0 5 5 3 2 2 5 I 2 6 0 0 2 0 0 0 0 0 0 0 0 0 8 15 18 0 0 0 100 100 100 BB3-1 BB 3 2 66 49 0 0 12 12 7 II 4 9 3 3 3 7 0 0 0 I 0 0 0 0 5 8 0 0 100 100 i BB 3 3 21 0 7 9 I 2 3 I 0 0 0 56 0 100 5!:'"'0 1:.'1 0\Z ('jjoooo( 0 = w ..... sr= ('j 0 c.= .._ .... s = Q. .._ ...... 1.0

PAGE 161

APPENDIX 4 PETROGRAPHIC DESCRIPTIONS FOR LITHIFIED SEDIMENTS AND HARDGROUNDS 150 Detailed petrographi c descriptions of lithi fied sediment samples and hardground samples are contained in the following table. This information is suplimentary to that which is given on core lo gs in Appendix 1

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151 APPENDIX 4. (Continued) SAMPLE# GBB-2 LU GBB-2 LL BB3-3 LU BB3-3 LL BB3-4 L STA-2 R STA-3 R BB3-5 R BB3-7 R BB3-9 R GBB-1 HG STA-2 HG DESCRIPTION Oopelsparite with variable Halimeda, forams and bioclasts Cement is very fine crystalline, fibrous, intragranular pore lining marine cement forming isopachous rinds around some grains same as above same as above same as above same as above, with an absence of ooids Oopelbiosparite showing multiple cementation events Some inter and intragranular spary cements, surrounded by micrite stringers. Possible episodes of dissolution and subaerial exposure followed by resuspension, deposition and further dissolution Large bivalve fragment which is partially recrystalli z ed. Sparite with very few identifiable grains Many micrite envelopes within fine to coarse crystalline inter and intragranular freshwater blocky spar. Primary calcite recrystallized by coarse blocky spar Biopelsparite with micritic stringers Cements are fine crystalline interand intragranular freshwater cements Highly recrystallized pelsparite. Micrite env e lopes are only remains of grains. Cements are fine to coarse crystalline interand intragranular spar (freshwater). Pelsparite with interand intragranular fine to medium crystalline spar cements (freshwater). Biopelsparite with abundant Halim e da fragments. Many micrite envelopes within a fine to medium crystalline drusy freshwater cement. (continued on next pag e )

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152 APPENDIX 4. (Continued) BB2-4HG BB2-5 HG BB2-6HG BB3-7 HG Pelsparite showing considerably less diagenetic alteration Inter and intragranular medium to coarse freshwater spary cements still exist. Sparite with few identifiable grains. Some gastropod and foram fragments. All primary calcite replaced by blocky spar Interand intragranular pore filling cements persist (freshwater) Pelsparite with variable Halimeda fragments. Primary calcite present in some fragments. Cements are pore filling spar Possible soil horizons identifiable by alveoli structures. Pelsparite exhibiting almost total recrystallization. Neomorphic recrystallization of primary calcite. Cements are fine to coarse crystalline inter and intragranular pore filling spar


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