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Coastal processes and anthropogenic factors influencing the geomorphic evolution of Weedon Island, Florida
h [electronic resource] /
by Jeanne Lambert.
[Tampa, Fla] :
b University of South Florida,
ABSTRACT: Weedon Island, a peninsula located on the western inner shoreline of Tampa Bay, Florida, is the location of a collaborative geological and archaeological project that aims to relate the present day geomorphology to natural processes and human occupational activity during the middle to late Holocene. The area is known for extensive archaeological sites, which were originally investigated in the 1920s, although they have received relatively little scientific attention during most of the last century. We hypothesize that activities associated with pre-historic human occupation of Weedon Island at various times during the last ca. 5,000 years influenced the geomorphic evolution of the peninsula. An interdisciplinary approach, including geomorphic mapping, sediment-coring, and archaeological survey and excavation, is being used to test our hypothesis and is expected to reveal the extent to which natural processes and human activities interacted to shape the present-day configu ration of the peninsula.A total of 41 vibra-cores have been recovered from Weedon Island in a series of transects from Riviera Bay, an inland body of water connected by tidal channel to Tampa Bay, across multiple dune ridges, depressions, freshwater wetlands, and forested uplands, to the pre-development eastern shoreline position. Coring has revealed multiple buried surfaces and archaeological midden deposits, which allow us to reconstruct the vertical aggradation of coastal and inland sediments. Initial radiocarbon dating on charcoal provides an age estimate of 1450 Â¨ 40 14C yr B.P. for the upper midden horizon. Wood fragments from a sand layer at the base of the core give a pre-occupation age of 3370 Â¨ 50 14C yr B.P. These dates and stratigraphic evaluations of sediment reveal possible paleoenvironmental shifts associated with mid to late Holocene sea-level rise, paleoclimatic shifts, and pre-historic human activity.More recent human impacts on the peninsula have impeded our efforts^ in some areas. During the twentieth century, dredging, mosquito ditching, and road construction, have disturbed the surface and portions of the upper sediment record in many locations. Sediments below obvious disturbances or in unimpacted areas of the peninsula, along with radiocarbon dating, have helped reconstruct the mid to late Holocene paleoenvironments and paleolandscape of Weedon Island.
Thesis (M.A.)--University of South Florida, 2006.
Includes bibliographical references.
Text (Electronic thesis) in PDF format.
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Adviser: Eric Oches, Ph.D.
x Environmental Science and Policy
t USF Electronic Theses and Dissertations.
Coastal Processes and Anthropogenic Factors Influen cing the Geomorphic Evolution of Weedon Island, Florida by Jeanne Lambert A thesis submitted in partial fulfillment of the requirement of the degree Master of Science Department of Environmental Science and Policy College of Arts and Sciences University of South Florida Major Professor: Eric Oches, Ph.D. Philip Van Beynen, Ph.D. Brent Weisman, Ph.D. Date of Approval: March 28, 2006 Keywords: geomorphology, sediment, Tampa Bay, shell midden, paleodune Copyright 2006, Jeanne Lambert
Acknowledgements Thanks to The Friends of Weedon Island for financin g 14C dating, Progress Energy for permission to access coring locations; P hyllis Kolianos and the Weedon Island Preserve staff for obtaining permits and hel ping with field work; and Jonathan Dean and Brent Weisman for their archaeological exp ertise. I would also like to thank the coring crew, with special thanks to the constan t members, Scott Anderson, Matt OÂ’Brien, and Dave Burns, as well as Jenn Sliko for her contributions and suggestions. Thanks to Jason Polk, Dan Dye, Phil Van Beynen, and Rick Oches for putting up with me and helping out on all the little problems along the way. Special thanks to my family and friends who have been there for me, I could not have finished without your love, guidance, sense of humor, and support.
i Table of Contents List of Tables iii List of Figures iv Abstract v Introduction 1 Background Site Location 4 Geologic Background 5 Sea level History 8 Paleoclimate 13 Archaeology of Weedon Island 16 Methods 21 Field Methods 21 Lab Methods 24 Results 26 Cores 26 Radiocarbon Dating 31 Aerial Photographs 37 Discussion 40 Fence Diagrams Descriptions 40 Fence Diagram A 40 Fence Diagram B 41 Fence Diagram C 42 Fence Diagram D 43 Fence Diagram E 44 Bed Interpretations 46 Comparison With Paleoclimate 48 Conclusion 52 References 54 Appendices 59 Appendix A: Core Digital Library 59
ii List of Tables Table 1 Core Data 23 Table 2 Facies Descriptions 29 Table 3 Radiocarbon Dates 31
iii List of Figures Figure 1. Site Location 6 Figure 2. Balsillie and Donoghue (2004) Sea Level C urve 10 Figure 3 Wanless Modified Sea Level Curve 11 Figure 4 Balsillie and Donoghue (2004) Sea Level Gr aph 12 Figure 5 Soto (2005) Oxygen Isotope Graph 15 Figure 6 Shell Tools Found on Weedon Island 19 Figure 7 Archaeological Shovel Pit Sites 21 Figure 8 Core Locations 27 Figure 9 Fence Diagram A 32 Figure 10 Fence Diagram B 33 Figure 11 Fence Diagram C 34 Figure 12 Fence Diagram D 35 Figure 13 Fence Diagram E 36 Figure 14 1943 Photograph with Paleoshoreline 38 Figure 15 1943 Photograph without Paleoshoreline 39 Figure 16 Paleoclimate Interpretation 49
iv Coastal Processes and Anthropogenic Factors Influen cing the Geomorphic Evolution of Weedon Island, Florida Jeanne Lambert ABSTRACT Weedon Island, a peninsula located on the western i nner shoreline of Tampa Bay, Florida, is the location of a collaborative geologi cal and archaeological project that aims to relate the present day geomorphology to natural pro cesses and human occupational activity during the middle to late Holocene. The area is kno wn for extensive archaeological sites, which were originally investigated in the 1920s, al though they have received relatively little scientific attention during most of the last century. We hypothesize that activities associated with pre-historic human occupation of We edon Island at various times during the last ca. 5,000 years influenced the geomorphic evolution of the peninsula. An interdisciplinary approach, including geomorphic ma pping, sediment-coring, and archaeological survey and excavation, is being used to test our hypothesis and is expected to reveal the extent to which natural processes and human activities interacted to shape the present-day configuration of the peninsula. A total of 41 vibra-cores have been recovered from Weedon Island in a series of transects from Riviera Bay, an inland body of water connected by tidal channel to Tampa Bay, across multiple dune ridges, depressions, fres hwater wetlands, and forested uplands, to the pre-development eastern shoreline position. Coring has revealed multiple buried
v surfaces and archaeological midden deposits, which allow us to reconstruct the vertical aggradation of coastal and inland sediments. Initia l radiocarbon dating on charcoal provides an age estimate of 1450 40 14C yr B.P. for the upper midden horizon. Wood fragments from a sand layer at the base of the core give a pre-occupation age of 3370 50 14C yr B.P. These dates and stratigraphic evaluations of sediment reveal possible paleoenvironmental shifts associated with mid to la te Holocene sea-level rise, paleoclimatic shifts, and pre-historic human activi ty. More recent human impacts on the peninsula have imp eded our efforts in some areas. During the twentieth century, dredging, mosq uito ditching, and road construction, have disturbed the surface and portions of the uppe r sediment record in many locations. Sediments below obvious disturbances or in unimpact ed areas of the peninsula, along with radiocarbon dating, have helped reconstruct the mid to late Holocene paleoenvironments and paleolandscape of Weedon Island.
1 Introduction Weedon Island, a peninsula on FloridaÂ’s West coast, protrudes into the estuary of Tampa Bay. Weedon Island is of geological and arch aeological interest due to its moderately well preserved (legendary) archaeologica l site and its placement in inner Tampa Bay. The outer barrier island chain and shel f area at the opening of Tampa Bay have been extensively researched (Davis, 2003), yet many regions within the bay have received less attention. The post-glacial inundati on history of Tampa Bay itself is still somewhat in question, though a better understanding of the region has recently been summarized by Donahue et al. (2003), suggesting a s unken fresh water depression that was inundated by marine waters around 5,000 BP. Su rveys on the inner bay may help clarify times and patterns of sea level fluctuation and major events that may have occurred within of Tampa Bay since marine inundatio n. The area is also known for its variety of archaeolo gical sites, which have characterized a civilization of western Florida. T hough the culture of the Weeden (sic) Island peoples (Note: known as such due to a misspe lling in 1920s archaeological literature) has been established through artifacts from limited Weedon Island archaeological excavations and excavations elsewher e, there was very little known about the prehistoric people of the actual Weedon Island site (Milanich, 2002). Reconnaissance archaeological surveys done in collaboration with o ur geomorphologic studies have located and recorded a range of previously undocume nted potential sites on Weedon
2 Island and revealed aboriginal technologies and occ upational periods (Weisman et al., 2005). Further knowledge of the area has been esta blished through our geological survey in which we reconstruct the geomorphic evolution of the peninsula during the late Holocene to help understand the paleoenvironmental relationships pertaining to the settlement patterns and timing of occupation events The purpose of this investigation is to reconstruct the geologic and paleoenvironmental evolution of the Weedon Island p eninsula as a context for the ancient civilizationÂ’s movements on the peninsula itself. Research Hypothesis: Prehistoric activities and cu ltural occupation and paleoclimatic changes influenced the geomorphic evo lution of Weedon Islands. Supporting Research Questions: 1. How did changes in sea level affect the geomorpholo gy and sedimentation processes of Weedon Island? 2. What is the relationship between human manipulation of the landscape and the natural sedimentation processes in the geom orphic evolution of Weedon Island? 3. What additional research will be required to asses the anthropogenic and paleoclimate effects on the islandÂ’s geomorphol ogy. Data from this investigation, through sediment core collection, demonstrate a transition from a freshwater environment to a shall ow brackish environment along the paleoshoreline. This is evident in the mud and pea t layers that rapidly transition to
3 shallow beach-face sands. In inland cores we saw e vidence of transitions from upland environments to more (saline/fresh) moist environme nts as well as transitions from arid dunal environments to more vegetated soil types as the water table and sea level rose.
4 Background Site Location Present day Weedon Island (Figure 1) consists of a 3,700 acre preserve owned by Pinellas County, the State of Florida, and Progress Energy Corp. The land has been jointly managed by all three entities since 1992. The preserve holds a vast variety of environments corresponding to upland, scrubland, an d marsh ecosystems. Elevation plays a key factor in the location of these ecosyst ems in the preserve. Dune complexes surround Riviera Bay along its northern and eastern shores, MasterÂ’s Bayou on its southern shore, and once flanked the paleoshoreline of western Tampa Bay. The rise of these dunes from 2.5m to 6.5 m above sea level resu lts in drastic differences in vegetation and soils. Mangrove marshes and tidal flats compri se most of the southern portion of the peninsula. Multiple springs and fresh to brackish lakes are located on the peninsula and its bordering islands. The northeastern portion of the peninsula has extensive alterations from the construction of the Florida Power electric ity generating facility. The island has undergone other historical changes d ue to fill activities, mosquito ditches, and additional human alterations during th e past century. Much of the area was cleared of vegetation to harvest pine trees, build roads and an airport runway, and construct houses and businesses during the late 19th and early 20th centuries. Portions of the area were also utilized for agricultural develo pment. Weedon Island residents, including Dr. Weedon himself, planted citrus groves over much of the northern and
5 eastern-midden capped dune ridges, which altered th e upper sediment layers. During the 1950s and 1960s extensive mosquito ditches were dug on the southern and northern portions of the peninsula to Â“improve healthÂ”. The ditches drastically altered the ecology and hydrology of the area, allowing marine waters a nd mangrove invasion into a once upland environment in the northern portion, and a f ormer mud flats ecosystem in the south. There has also been significant looting of the archaeological sites throughout the last century. Large conspicuous looting ditches ca n still be identified, especially along the large northeastern midden complex excavated by Fewkes in 1924. All of these historic and recent alterations have hampered our a bility to reconstruct the past environments of Weedon Island. Geologic Background Weedon Island is really not an island at all, as ca n be seen in Figure 1. It is a peninsula located on the inner western edge of Tamp a Bay. Tampa Bay is FloridaÂ’s largest estuary, with a surface area of 1032 km2, and an average depth of less than 4 meters is located on the extensive Neogene carbonat e Florida Platform (Duncan et al., 2003; Donahue et al., 2003).
6 Figure I. A) satellite image showing the state of Florida. B) satellite image displaying the Tampa Bay region located on the western Florida coast. C) aerial photo of Weedon Island, which is located on the inner western edge of Tampa Bay. Th is study focuses on the northern portion of Weedon Island, outlined by the box. The Florida platform, which developed since the Eoc ene period, is a tectonically stable environment created mainly from cycles of ca rbonate and siliclastic sedimentation (Smith and Lord, 1997). The Florida Platform lies between two provinces of sediment: the North Gulf sedimentary province and the Florida Peninsula sedimentary province.
7 During the Holocene, sedimentary deposits consisted mainly of siliclastic, carbonate, and organic sediments (Scott, 1997). Throughout history, the Florida platform has been c ontinually shaped and reshaped by the inundation and retreat of the ocean s (Hine, 1997). The gently sloping platform, with a maximum elevation of 104 meters, a llows for small sea level rises to have great impacts on the environment of the region (Hine, 1997). Freshwater lakes turn quickly into marine environments with the onslaught of rising sea levels, and when seas subside, areas become exposed dry land (Beck, 1984) The rate at which the sea level rises plays a crucial role in the development of co astal morphology (Schmidt, 1997). The Tampa Bay region is a low energy sedimentation environment influenced mainly by tides. Though the tidal range for the ar ea is less than one meter, Tampa Bay, because of its size, has an impressive tidal prism. These large prisms can greatly influence the geomorphology of the estuaryÂ’s tidal inlets (Hine, 1997). Other influences include impacts by tropical storms during the summe r and frontal systems during the winter (Davis et al., 2003). Although infrequent, hurricanes along FloridaÂ’s Gulf Coast can play a major role in geomorphic changes of the area when they do occur (Davis et al., 2003). There are four general theories for the formation o f Tampa Bay. Stahl (1969) believed that the topography of the area may have h ad an impact on surface drainage patterns. These patterns may have influenced erosi on of local features to create the Tampa Bay depression. Hebert (1985) believed the b ay area was influenced more by karstification of the Miocene valley system, which has been recognized on the shelf. This caused the dissolution of limestone and the cr eation of depressions. Bathymetric
8 and seismic surveys on the coastal shelf help revea l the complex nature of this system, and the theory was later expanded upon by Hine (199 7). Hine (1997) hypothesized that during periods of low ered sea levels and increased water flow through the Tampa Bay system, the rates of dissolution of limestone may have increased on the shelf-valley systems. This may ha ve caused a receding shelf-valley system and helped to create the present day Tampa B ay (Hine 1997). On the other hand, Donahue et al. (2003) suggest that there is no evid ence of an estuarine or shelf retreat path. Instead they propose that the present Tampa Bay was a mid-platform depression that contained freshwater wetlands and acted as a d rainage basin for much of the central peninsula. The freshwater depression system was qu ickly inundated by marine transgression which flooded the area during the lat e Holocene. Sea Level History The rise and fall of sea level and the rate at whic h it occurs remains the central issue to the theories for the formation of Tampa Ba y described above. During glacial periods a significant amount of water is stored in glaciers and snow cover in the higher latitudes. In response, ocean levels decline, less precipitation falls in the subtropics, causing the land to dry, and cooler ocean temperatu res cause a reduction in evaporation rates. The last major ice age maximum was around 2 0,000 years B.P., at which time sealevel was as much as 140 m below present level. Si nce the ice sheets began retreating about 15,000 years ago, sea-level has steadily rise n, although with periods of minor reversals and fluctuating rates documented in the g eologic record.
9 FairbridgeÂ’s (1974) sea-level curve, which is based on radiocarbon data and geomorphologic evidence from around the world, show s a eustatic sea level height similar to the present by about 6,000 years B.P. (G leason, 1984). The actual height of the oceans has changed very little in the last 3,500 ye ars, oscillating a few feet since then, but the volume has recently begun to increase (Dorsey, 1997). RobbinÂ’s (1984) study in the Florida Keys shows evidence of slow-fast-slow trend in the rates of rise. He suggests a rate of rise of 0.3 mm/yr from 14,000 to 7,000 yrs B.P., 1.2 mm/yr from 7,000 to 2,000 yrs B.P. and 0.3 mm/yr from 2,000 yrs B.P to the pr esent (Robbin, 1984). SchollÂ’s 1969 curve, based on radiocarbon-dated samples of peat f rom South Florida also shows a constant overall sea level rise, but with varying r ates (Gleason, 1984). Gleason (1984) found a similar continuous sea level rise through h is study of the Florida Keys. Some investigations have suggested, mainly utilizing evi dence from shell midden sites and dune scarps, that there was a higher-than-present s ea-level stand during the mid to late Holocene (Blum et al. 2001; Morton et al., 2000; St apor et al., 1991). In GleasonÂ’s study of the Keys, there was no evidence to suggest a hig her than present sea level during the Holocene. Closer to our study area, no higher than present mid-Holocene sea level stand was found along the Suwannee River coastline, but v arying rates of rise for the area were estimated (Wright et al. 2005). Figure 2 is a comp ilation of data from several studies reconstructing changes in sea-level during the past 5,000 years.
10 -2-1 012345678 0100020003000400050006000 DEPTH of MSL (m) C-14 years BP (MSL) Scholl and Stuiver (1967) Stapor et al. (1991) Froede (2002) Goodbred (1998) Walker (1994) Fairbanks (1990) Figure 2. Sea-level studies are represented by dif ferent colored lines and data points within the graph taken from Balsillie and Donoghue (2004). Th e data points and lines have been graphed to represent researched data for sea-level heights from present day to 5,000 yrs B.P. Wright and others (2005), from their extensive stud y of the Suwannee River region, established rates of sea-level rise for the stable northern Gulf Coast of Florida. Using marsh deposits Wright and others identified a rate of rise for the area of 0.16 cm/yr between 7,500 and 5,500 cal yr BP. The rise slowed to 0.07 cm/yr between 5,500 and 2,500 cal yr BP, and slowed even further to 0.05 cm /yr between 2,500 cal yr BP and 750 cal BP. Wanless (1994) also amassed information fr om a variety of sources to establish a general sea level rate of rise curve for the coast of Florida. Figure 3 shows an overview of his curve estimating sea level rate of rise for the West Coast of Florida over the Holocene (Wanless, 1994).
11 Figure 3. The Holocene sea level rate of rise curve was compiled by Wanless et al. (1994), and illustrates the variations in the rate at which the sea is rising in South Florida. This graph was created using stratigraphic studies from throughout South Florida.
12 One of the most recent compilation efforts was done by the State of Florida Environmental Protection Agency and the Florida Geo logical Survey. Balsillie and Donoghue (2003) compiled 23 data sets from what are presently on shore and marine locations. They then compared these two separate r econstructions with a global (eustatic) sea-level curve. Figure 4 illustrates their findin gs for the middle to late Holocene. Figure 4. Comparison of the Gulf of Mexico younger data set compiled by Balsillie and Donoghue (2003) with the Siddall et al. (2003) eustatic sealevel curve. The Younger data set A is a compilation of data from presently marine positions from 23 sources. The Younger data set B is a compilation of presently onshore data from 23 sou rces. The variations in sea level and rates of change pla y a major role in the geomorphic evolution of the coastline. All of the above research suggests that sea-level has changed throughout the Holocene and that the ra te at which it has changed has also fluctuated. Donahue et al. (2003) postulated a mod el for the development of Tampa Bay as sea level has fluctuated over the Holocene. The model shows Tampa Bay as a sunken fresh water depression from 11,000 yr B.P. to aroun d 5,000 yr B.P., when the depression was quickly inundated by marine water. This create d a shallow protected estuarine
13 environment suitable for mangrove and sea grass dev elopment. The rate of sea level rise was more rapid (around 10m/1000yrs) until 3,000 yr B.P., when it slowed as it reached a level near the present position, which correlates w ell with both Wanless (1994) and Wright (2005) curves. The slow rate of rise allowe d for sediment accumulation and development of coastline features such as barrier i slands and extensive mangrove systems, which are seen along FloridaÂ’s west coast (Donahue, 2003). Thus far there is very little information on how the sea level oscill ations and rates of change have affected the inner portion of Tampa Bay where Weedon Island is situated. Paleoclimate Present climatic conditions in the Tampa Bay area a re representative of a subtropical climate. The average summer and winter temperatures are 32C and 17C degrees Celsius, respectfully, and the area has an average rainfall (exclusive of hurricanes) of about 1170mm (NOAA Climate Data Cent er, 2006). More than half of the precipitation occurs during the wet season which ru ns from June through September and overlaps with the hurricane season (June-November). Precipitation in the region is highly influenced by regional climatic factors such as El Nino, the location of the Intertropical Convergence Zone (Cane, 2005), and th e position of the Bermuda High (Stahle and Cleveland, 1992). Throughout the Holocene, changes in FloridaÂ’s clima te have been influenced by changes in the regional climatic features listed ab ove. These features may themselves be influenced by a variety of events following the las t glaciation such as the EarthÂ’s orbital parameters (Milankovitch Cycles), and effects of de glaciation meltwaters flushing into
14 the Gulf of Mexico and the Northern Atlantic (Poore et al., 2003; Oglesby et al., 1998; Curtis and Hodell, 1993). The lack of high resolut ion studies has impeded reconstruction of a precise paleoclimate history for Florida durin g the Holocene (Otvos, 2005). Previous studies have focused on lake sediment anal ysis and tree ring studies, such as those at Camel Lake, Lake Tulane, and Little Salt S prings. The early Holocene is characterized by drier and cooler conditions until around 8,500 yr B.P. (Poore et al., 2003; Watts, 1980). A study at Little Salt Spring study indicates drier than present conditions from between 9,300 and 5,900 yr B.P., a wet period beginning about 5,000 yr B.P. until around 2,800 yr B.P., semi-arid conditio ns peaked between 2,700 and 1,900 yr B.P., and precipitation once again increased, peaki ng at 1,000 yr B.P. (Alvarez et al., 2005). The sediment record at Little Salt Spring i s low resolution with considerable uncertainty in the age estimates. But wetter condi tions beginning at 5,000 yr B.P. do correspond well with the increasing El Nino intensi ty beginning around the same time (Cane, 2005). A recent paleoclimate study in Florida, and the fir st one involving speleothem isotopic analysis, confirms the tree ring precipita tion models for the SE U.S. from 1,000 yr B.P. to the present (Soto, 2005). The speleothe m record extends the tree ring record, giving high resolution data on precipitation back t o 4,200 years B.P. (Soto, 2005). Soto (2005) found that the Atlantic Multidecadal Oscilla tion, with a cyclicity of about 60 years, appears to have the greatest impact on preci pitation in Florida. Their study also correlates well with the lake sediment studies list ed above and estimated precipitation variations as well as CaneÂ’s (2005) study of El Nin o events during the Holocene. Figure
15 5 is a graph of Soto (2005) speleothem isotopic dat a indicating the wetter and drier periods. Figure 5. Oxygen Isotope data from Soto (2005) ind icates periods of wetter and drier than average conditions in Florida as seen in two separa te speleothems from two separate caves. The top graph shows the oxygen isotope data for spe leothem labeled BRC03-02 from cave Brooksville Ridge Cave (BRC) in Hernando County Flo rida. The lower graph shows the oxygen isotope data for speleothem BRIARS03-02 from Briar cave in Marion County Florida. As shown in Figure 5, periods of drier than averag e conditions occurred at 3.5 ka BP, 2.75 ka BP, 1.75 ka BP and from 0.8 ka to the p resent. Wetter than average conditions are noted with peaks at 1.8 ka BP, 1.3 k a BP, and 0.9 ka BP. These dates are
16 associated with larger peaks, but there are also ma ny small oscillations, especially within the more detailed BRIAR cave record. All but the d rier period around 0.9 ka BP appear to correlate well with the previous paleoclimate re cords described from Lake Tulane and Camel Lake. Archeology of Weedon Island It has been estimated that humans arrived in Florid a between 14,000 and 12,000 years B.P. (Milanich, 2002). Their impacts along t he coast have been studied at many locations. It is important to understand the role these ancient humans may have played in the creation of Weedon Island as it exists today be cause of their possible impact on the geomorphology of the area. A greater understanding of the archaeology of the area will assist in the determination of occupational periods which may correspond with particular wet/dry periods and may have been influenced by sea level fluctuations. The Weeden Island periods I and II are generally de fined by their pottery types and chronologically come after the Santa Rosa and S wift Creek Periods (Willey, 1949). The two periods show general dates from A.D. 200/30 0 to 750 and A.D. 750 to 900-1000 (Milanich, 2002). The extent of the culture reache s down the Gulf Coast to Manatee and Sarasota counties, northward to the coastal plains of southern Georgia and Alabama, east to the Okefenokee swamp region, and west to Mobile Bay (Milanich, 2002). The sites themselves generally were small in extent with typi cal diameters of less than 100 meters (Willey, 1949). These sites were concentrated arou nd sheltered brackish and salt water environments, including coves, bays, lagoons, sound s, and estuaries (Milanich, 2002). The socioeconomic structure was centered around the natural resources provided by the
17 coastal marshes and tidal streams such as mollusks and oysters, which are the predominant shells found in middens (Milanich, 2002 ). Weedon Island archaeology was explored and partiall y excavated in 1923-24, and was reported by Fewkes (1924). His study found thr ee basic different types of shell mounds, which he labeled as burial mounds, rubbish mounds, and possibly domiciliary mounds; but there is no direct evidence associated with the third type of mound as having buildings on it. Fewkes (1924) postulated that the mounds themselves may have been dunes previously, but evidence points towards artif icial construction (Willey, 1949). Most of the ceramics Fewkes found in the shell midd ens were plain ware. Therefore, he did not associate the people who built the burial m ounds and used Weeden Island pottery, with those who lived in the village and used the pl ain pottery (Milanich, 2002). Within the few excavation areas, it was determined by Stirling, who worked with Fewkes on the excavation, that there are three dist inct layers of deposition (Willey, 1949). These include a top layer about 4 inches in depth presumed to be deposited since occupation, and 2 layers containing skeletal remain s which show very different burial techniques. Stirling believed the bottom layer to have been the original ground surface where depositions of burials as well as pottery and non-ceramics were more depicting of the Glades culture than the Weeden Island culture ( Willey, 1949). The upper layer collection of burials, pottery, and non-ceramics we re more typical of the Weeden Island II culture. The collection as a whole was incomple te, lacking information on any Weeden Island I culture, and many artifacts are mis sing. There were not any numerical ages determined, and therefore the time periods are only generalized (Willey, 1949).
18 These findings lead some archeologists to wonder wh ether or not Weedon Island itself can be considered an actual Â“trueÂ” Weeden Island I site (Milanich, 2002). A recent comprehensive cultural resource survey of the Weedon Island Preserve by Weisman and others (2005), done in collaboration with this project, revealed a number of possible human interactions with Weedon Island. They found the site to be of great significance because, despite many disturbances, a substantial area of the site is still preserved. These preserved deposits allow archaeol ogists to determine Late ManasotaWeedon Island subsistence, technology, social organ ization, and political economy. A great diversity of pottery in terms of style, tempe r, and potform were found on the site leading to questions concerning pottery production and uses. Various tools were also found amongst the sand layers. A significant reduc tion sequence not yet described elsewhere in literature was worked out for a colume lla tool found on the site (Weisman et al., 2005). Figure 6 shows some of these unique to ols made from shells found on Weedon Island by the cultural survey.
19 Figure 6. Shell tools were found on Weedon Island d uring the cultural survey. The smaller ones had not been identified in previous literature and a reduction sequence for the toolsÂ’ creation was discovered and documented by Jonathan Dean. Figure from Weisman et al. (2005). Archaeological artifacts, including tools and evide nce of tool production and culinary activities, found within yellow and white sand layers, suggest two separate
20 occupational periods. Both the Late Archaic groups and the latter Manasota-Weedon Island people lived on or adapted to a dunal settin g. Those occurring within the yellow sand layer have been associated with the Middle to Late Archaic Period occurring around 5,000 years ago. The white sand layer overlaying t he yellow sand contains artifacts indicating that people (Manasota-Weedon Island) wer e inhabiting the dune ridges during and after deposition. Shell scatters within white sand layers may have occurred prior to midden deposition, which occur predominantly above the white sand layer (Dean, personal communications, 2006). Figure 7 shows loc ations of shovel pit sites explored during the survey.
21 Figure 7. Yellow dots represent locations where sh ovel tests were taken during the archaeological inv estigation of Weedon Island. Along with these shovel tests soil probes and transects were also done in conjunction with th is study. For further information on the archaeological findings on Weedo n Island refer to Weisman et al. (2005).
22 Methods Field Methods In order to reconstruct the geomorphic evolution an d give a general overview of environmental sedimentation for Weedon Island penin sula, multiple transects were selected for sediment core collection. Transects e xtend from what is interpreted as the paleoshoreline of Tampa Bay on the eastern and nort hern edges of the peninsula, across the upland environments and lowlands that encompass the peninsula south and westward to Riviera Bay (Figure 8). Within these transects cores were taken depending topography and accessibility. Forty-one sediment cores were c ollected using the basic vibracoring technique described by Lanesky et al (1979). 10 cm Aluminum core tubes were vibrated into the ground at previously selected locations an d extracted using a coring tripod and winch. Excess core tube was trimmed using a pipe cu tter, and core tubes were capped. Once transported to the lab, cores were cut into ap proximately one meter sections using a pipe cutter and then split lengthwise using a blade saw and stored in plastic sleeves for further analysis. Figure 8 shows the locations of the core sites within the five transects; cores 04WI2, 04WI4, 04WI6, 04WI8, 04WI10, 04WI12, 0 4WI14, 04WI15, and 04WI17 are duplicates, and cores 04WI11, 04WI13, 05WI18, 0 5WI31, 05WI32, and 05WI39 are outside of any transect. Table 1 lists core collec ted, their locations, lengths, and topographic position.
23 Table 1. All cores collected in the course of this study are listed with their identification number, date collected, North and East UTM coordinates, tot al sediment recovered in centimeters, compaction in centimeters, fence diagram in which t he transect is represented, and description of the environment/landform where the core was taken. Cores represented by NA for their transect are either are either duplicates or are outside of any transect. Cores duplicates include 04WI2, 04WI4, 04WI6, 04WI8, 04WI10, 04WI12, 04WI14, 04WI15 and 04WI17. Cores outside of transects include cores 04WI11, 04WI13, 05WI18, 05W I31, 05WI32, and 05WI39. Core Number Date Collected UTM North UTM East Rec. (cm) Comp. (cm) Transect Description of location 04WI1 3/22/2004 3082722 341749 154 96 B midden ridge 04WI2 3/22/2004 3082724 341747 162 121 NA midden ridge 04WI3 4/5/2004 3082627 341796 269 60 B estimated paleoshoreline 04WI4 4/5/2004 3082628 341795 121 110 NA estimated paleoshoreline 04WI5 4/5/2004 3082436 341691 260 101 B dune ridge 04WI6 4/5/2004 3082437 341690 121 105 NA dune ridge 04WI7 4/5/2004 3082229 341567 260 43 B upland 04WI8 4/5/2004 3082226 341565 241 68 NA upland 04WI9 4/5/2004 3081656 341497 250 51 D edge of Riviera Bay 04WI10 4/5/2004 3081655 341496 411 29 NA edge of Riviera Bay 04WI11 10/30/2004 3082888 341819 172 122 NA estimated paleoshoreline 04WI12 10/30/2004 3082887 341818 289 58 NA estimated paleoshoreline 04WI13 10/30/2004 3082849 341805 81 0 NA upland 04WI14 10/30/2004 3082840 341805 71 0 NA upland 04WI15 10/30/2004 3082199 341495 211 63 NA wetland 04WI16 10/30/2004 3082196 341494 255 89 B wetland 04WI17 10/30/2004 3082048 341345 281 37 NA dune ridge 04WI18 10/30/2004 3082046 341340 315.5 44 B dune ridge 05WI18 1/27/2005 3082414 340579 239 37 NA dune ridge 05WI19 1/27/2005 3082298 340579 337 9 E wetland 05WI20 1/27/2005 3082281 340581 343 0 E dune slope 05WI21 2/3/2005 3082259 340453 223.5 81 E midland 05WI22 2/3/2005 3082258 340456 326.5 20 E dune ridge 05WI23 2/3/2005 3082293 340776 335 4 C lowland 05WI24 2/3/2005 3082289 340838 246.5 81 C midland 05WI25 2/11/2005 3082358 341094 249.5 2 C dune ridge 05WI26 2/11/2005 3082304 340989 255 97 C dune ridge 05WI27 2/11/2005 3082281 340838 289 58 C dune slope 05WI28 2/11/2005 3082281 340447 251 45 E dune slope 05WI29 2/17/2005 3081883 341551 232 38 D dune slope 05WI30 2/17/2005 3082103 342022 299 38 D lowland (Table 1 continued next page)
24 Table 1. (continued from p. 23) 05WI31 2/17/2005 3081791 341805 224 67 NA lowland 05WI32 2/17/2005 3081812 341691 257 24 NA lowland 05WI33 2/17/2005 3081905 341622 208 115 D wetland 05WI34 2/24/2005 3082756 341204 188 162 A midden ridge slope 05WI35 2/24/2005 3082744 341219 208 97 A midden ridge 05WI36 2/24/2005 3082685 341221 328 172 A lowland 05WI37 2/24/2005 3082734 341063 235 60 A lowland 05WI38 5/10/2005 3082184 340400 504 70 E Riviera Bay 05WI39 5/10/2005 3081533 341458 434 143 NA Riviera Bay 05WI40 5/10/2005 3082232 340773 318 69 C Riviera Bay Lab Methods A trowel was used to scrape excess sediment from th e cores, and one half of each core was then wrapped in plastic to serve as an und isturbed archive. All cores were photographed prior to further analysis. Visual str atigraphic and lithologic descriptions of sediment size, composition, structure, Munsell colo r, and organic content were then constructed for all cores. Core logs are presented in Appendix A. Three radiocarbon samples were taken from cores 04WI-1 and 04-WI-3. A few small pieces (few mm) of charcoal were extracted at 51cm below ground surface (BGS) from the shelly midden layer of core 04-WI-1. Fibr ous rootlets, with no obvious surface connections, were collected [in core 04-WI-3] from a bedding plane in finely laminated, carbonate mud at a depth of 81 cm BGS. Finally, woo d fragments were collected from a sand layer at the base of core 04-WI-3, at 268cm BG S. These were assumed to pre-date the thick homogeneous carbonate clay bed above. Th e radiocarbon samples were collected to target two events: 1) age of the midde n deposits in an inland, upland core,
25 and 2) bracketing ages for the unusual carbonate mu d beds within a core interpreted to be from a nearshore paleoenvironment. Selected core descriptions and photographs have bee n applied along with the three radiocarbon age estimates to reconstruct lith ologic and geomorphologic changes for the transects. Fence diagrams were created to corr elate selected cores and stratigraphic units across the transects. Maps and aerial photographs were also used to deter mine recent historical changes that have occurred on Weedon Island. This was essential in determining an approximate historical shoreline of the peninsula p rior to the extensive mosquito ditching activities and artificial fill associated with powe r plant construction on the northeast portion of the island. These aerial photos and map s were obtained from various county and state sources and orthorectified (if not alread y in the proper format). They were then processed and analyzed using ArcGIS software. A m ap of present geomorphic settings was created for comparison with possible previous s edimentation environments. Digital elevation models and USGS topographic maps from Pinellas County, Florida were also employed for estimation of elevat ions of core sites and topographic features in the study area. The 10 meter DEM, in A ppendix B, was enhanced and corrected in Arcscene prior to the addition of cor e locations and an aerial photo overlay.
26 Results Cores: Photos and descriptions of each core are contained in Appe ndix A. Cores representing five transects across selected landfor ms and environments were assembled into fence diagrams. Figure 8 shows the locations of each core transect as well as the cores used for each fence diagram. Table 1 lists a ll cores collected in the course of this study.
27 Figure 8. The red dots indicate locations where cor es were taken on Weedon Island. The lettered boxes indicate groups of cores that are represented in fence diagrams A through E (Figures 913). Some cores were not represented within fence diagrams due to their locations or because they are duplicates of others used in the fence dia grams. Transects were selected based on topographic positi on, targeted landforms, archaeological relevance, and accessibility. Trans ect A extends across a midden-capped dune ridge and is located just south of MasterÂ’s Bo you. Numerous archaeological artifact
28 sites are scattered throughout this transect area. Four cores were taken to represent transect A. One core was taken on the top of the d une ridge, one on both the northern and southern slopes, and one on the northern slope west of the other three locations. The fourth core was taken to determine the distribution of midden material. Transect B contains six cores and runs from northeast to the s outhwest across midden capped dune ridges containing artifacts, low lying freshwater w etlands, to the western dunes lining Riviera Bay. The northeastern most core (04-WI-13) in this transect is positioned on what we have interpreted as the paleoshoreline. Tr ansect C is situated near Old Weedon Island drive, which lies atop a high dune ridge run ning along the northern edge of Riviera Bay and is close to archaeological test sites. Tra nsect D extends northeast to southwest past a small lake, to the dune ridge along the east ern edge of Riviera Bay. The transect was selected in order to try and determine the exte nd of the wetland, presently known as Boy Scout Lake, in the past. Transect E begins in Riviera Bay and extends in an irregular pattern northeast across two dune ridges. Cores we re taken in Riviera Bay in order to determine whether a freshwater-marine transition co uld be identified in the sediment record (cores 37-40). Additional cores (04WI11, 04 WI12, 04WI13, and 04WI140) were collected in the Northeastern most part of the stud y area, in the transitional zone, between natural sediments and construction fill, in order t o further delineate the paleo-shoreline. Sediment types were categorized and symbols for eac h facies were assigned. Descriptions of each core facies are found in Table 2.
29 Table 2. List of facies identified in Weedon Islan d Cores. Symbols correspond to those used stratigraphic columns in figures 9-13 Facies Name Description Symbol Archaeological shell midden Characteristic of a layer containing many, approximately 80%, large and small mollusk shells. Bones, charcoal, and other organic material may als o be present. The boundaries are generally distinct. These layers have been identified during the archaeological reconnaissance survey as being anthropogenic created midden layers containing artifacts. Brown sand Characteristic of a layer containing dark brown ver y fine grained sand with medium amount of organic content. Very similar to the very pale brown sand layer, but sand is considerably darker in color. Brown highly mottled sand Characteristic of a layer containing pale brown to brown highly mottled with yellow, white, and brown sand. Organic content is generally moderate to hig h, approximately 50% or more. The layer often appears marbled and differs from the mottled white and brow n sand layer with the high organic, mostly root, cont ent. Brown highly mottled sand with shell fragments Characterisitc of a layer containing pale brown to gray, highly mottled, very fine sand. Organic cont ent consists of few to medium amounts of shell fragment s. Brown sand with shell fragments Characteristic of a layer containing pale brown to brown highly compacted fine grained sand. Many, approximately 70%, tiny well mixed shell fragments are found within this type of layer. Boundaries ar e relatively distinct. Coarse sand and gravel Characteristic of a layer containing white to gray very fine sand with many approximately 80% or more, solid white to very pale brown chunks. Tiny pieces of crushed shells are typically the only organic conte nt present. Dark yellow reddish-brown sand Characteristic of a dark brown to yellowish brown v ery fine sand. Generally the layer is darker in color near the top and gradually becomes lighter. Organic material is found in small amounts, generally consisting of a few tap roots. The sand has a rust y metallic glimmer that is characteristic of sands containing maganese.
30 Grayish brown sand Characteristic of a layer containing grayish brown very fine sand with few, about 20% or less, organic materials. This layer generally occurs below a lay er with high organic content, but tends to be comprise d mainly of sand itself. Carbonate mud Characteristic of a layer containing high, approximately 90% or more, calcium carbonate clay sized sediment. The color of the clay ranges from a white (5Y8/1) to a dark bluish gray (5PB4/1) and is often finely laminated. The boundaries are abrupt and very distinct. Light gray sand and detritus Characteristic of light gray, very fine grained san d containing medium to high, 30-70%, amounts of detritus material. This layer is located at the to p of most cores, which corresponds well with its interpretation as top soil. Light gray sandy clay Characteristic of a layer containing light gray to very pale brwon sand with a medium carbonate content. The sand appears cemented when dry. Mottled white and brown sand Characteristic of a mottled mixture of white and li ght brown very fine sand, giving a marbled appearance. Organic content is moderate to few, approximately 20%, and consists of mainly roots. Organic-rich mud Characteristic of dark brown to black organic rich layer. The sand content is low, approximately 10-20%, and there is a noticeable organic smell. Organic-rich sandy mud Characteristic of a layer containing grayish brown to dark brown compressed fine grained sand. Many flaky roots are present up to, about 70%, but the l ayer contains a higher content of fine grained sand than the 'mud' or 'peat' layers. Peat Characteristic of a layer containing a high percent age, approximately 70% or more, of densly compressed flakey roots. The sediment is generally dark brown with approximately 30% or less being fine grained sand. Very pale brown sand Characteristic of very pale brown very fine grained sand. These layers generally contain well mixed sa nd with some bioturbation mainly from plants. Organic material gernerally consists of a few to medium amount of tap roots. White sand Characteristic of a layer containing white (10YR8/1 or 10YR7/1) very fine single grained sand. The layer generally contains few, about 20% or less, organic content and is typically homogenous throughout. Organic content present usually consists of tap roo ts. Few to medium amount of tiny black phosphate flecks are also seen in this type of layer.
31 yellow sand Characteristic of a layer containing homogenous yellow (10YR8/6) very fine sand with few, about 20% or less, organic material. The organic content pre sent typically consists of a few long tap roots. Radiocarbon Dating Radiocarbon samples were measured by University of Arizona NSF-AMS lab. Radiocarbon age estimates were calibrated using the Cologne Radiocarbon Calibration software, CalPal ( www.calpal.de ). An age estimate of 1453 36 14C yr B.P., determined on charcoal from the 04WI1 core midden layer, is co mparable to radiocarbon ages determined on archaeological materials associated w ith aboriginal occupation in the area (Weisman et al., 2005). Ages acquired for the 04WI 3 core indicate that the calcium carbonate sediment layers formed between 3369 45 and 456 36 14C yr B.P. Table 3 lists radiocarbon samples measured and their calibr ated results. Table 3. Radiocarbon age estimates determined throu gh this study. 14C ages were calibrated using the Cologne Radiocarbon Calibration software ( www.calpal.de ). Sample ID Material 14C age BP Calendric Age calBP Calendric Age calAD/BC 04-WI-1-51 charcoal 1,45336 135028BP 60028AD 04-WI-3-81 fine roots 45636 51215BP 143815AD 04-WI-3-268 wood 336945 361360BP 166360BC Stratigraphic columns arranged in fence diagrams ( Figures 9-13) indicate the different facies within each core and correlations between cores across transects shown in figure 8. Core elevations are estimates based on t opographic maps and field notes. The elevation differences are not accurate; they are ge neralizations to show relative differences in topographic position within each tra nsect. Detailed core descriptions and photographs are compiled in Appendix A.
32 Figure 9. This figure represents transect A, cores 05WI34-37. These cores transect the northern-most midden-capped dune ridge.
33 Figure 10. Transect B extends northeastward from t he intersection of Weedon Island Drive and Progress Energy Road, across the midden-capped dune ridge, t o the paleoshoreline. The transect encompasses pre sent day upland, midland, and lowland environments
34 Figure 11. Transect C, which includes cores 05WI40, 05WI23, 05WI24, 05WI27, 05WI26, and 05WI25, extend s eastward along the dune ridge on the northern edge of Riviera Bay. Core 05WI40 was taken about 100 me ters offshore in the northern portion of Riviera Bay; th e rest of the cores were onshore just north of core 05WI40.
35 Figure 12. The figure represents Transect D, with c ores 04WI9, 05WI29, 05WI33, and 05WI30. This irregular transect extends from the eastern shore o f Riviera Bay, east, then south across a dune ridge ending northeast of Boy Scout Lake.
36 Figure 13. Transect E contains cores 05WI38, 05WI21 05WI22, 05WI28, 05WI19, and 05WI20, which crosses the dune ridge beginning at the northwest end of Riviera Bay. The cores make a northeasterly transect from core 05WI 38, which was taken about 100 meters offshore, across an east-west tren ding dune ridge to an upland area north of Weedon I sland Drive.
37 Aerial Photographs As seen in Figures 14 and 15, the paleoshoreline an d paleodune ridge can be viewed on the rectified 1943 aerial photograph. Th is photo provides a geomorphic perspective prior to large-scale alteration of the natural shoreline and topography through the construction of the Progress Energy power plant in the northeastern part of the study area. The locations of core sites are shown in rela tion to the natural shoreline position. It is also noteable to recognize that the paleodunerid ges and paleoshoreline are not the same location. There was a low lying possibly tidal fla t or marsh area in between the dunes and the beach zone.
38 Figure 14. A 1943 aerial photo, from Pinellas Coun ty Florida, was georectified and utilized to digiti ze the paleodune ridge as well as the paleoshoreline prior to power plant construction. The cores that are c losest to the paleoshoreline and paleodune ridge near the fill ar ea have been labeled.
39 Figures 15. The digitized lines created from the 19 43 photograph were overlayed directly onto the most recent aerial photo from Pinellas County Flori da.
40 Discussion Fence Diagrams Descriptions Fence diagrams were created for the core transects (Figures 9-13) in order to determine the geomorphic changes that occurred on W eedon Island and how humans may have impacted the evolving geomorphology of Weedon Island. Fence diagram A (Figure 9): The base of core 36 contains dark brown metallic sa nd possibly due to higher amounts of maganese, colored and organically enrich ed probably by an adjacent spring or standing freshwater. The pale brown and yellow san d in cores 34, 35, 36, and 37 correspond with a drier period of vegetated upland landscape. The darker sand layer in core 37 correlates with these layers, but its proxi mity to the inlet resulted in wetter conditions and greater organic matter accumulation and preservation. White eolian (dune) sand layers in core 36 correlate with the gr ay sand layers in cores 34, 35, and 37, which were darkened due to leaching of organics fro m the overlying archaeological shellmidden layers. No midden material is identified in core 36, possibly due to its position farther from the shoreline or proximity to a former fresh water source. Organic rich mud above the midden horizon in core 37 is indicative o f inundation either by freshwater or migration of the nearby tidal inlet, or could repre sent highly compacted saw palmetto and other vegetation root matter. The vegetation envir onment, midland containing concentrations of palm trees and saw palmettos, nea r core 37 suggests that the second explanation for the organic rich mud horizon may be more acceptable. A yellow sand layer separates two midden horizons in core 35. The two distinct midden horizons may represent two separate periods of habitation or may simply indicate reworking during
41 20th century human activities. Further dating of t he shell material is needed in order to confirm the possible explanations. Fence Diagram B (Figure 10): The base of core 3, located at the paleoshoreline, contains two separate layers of peat formed within a moist environment, directly above a layer of pale brown sand that is radiocarbon dated to 3,369 + 45 14C yr B.P. The lower pale brown sand layer does n ot contain shells, and most likely represents a vegeta ted dry land environment prior to marine inundation. Above the peat layers in core 3 is an abrupt transition into a homogeneous, finely laminated, carbonate clay, poss ibly created in a zero-energy lacustrine or lagoonal environment by whiting event s. Above the carbonate layer, highly fragmented shelly sand, representing a beach face e nvironment, indicates a paleoshoreline position. A coarse sand and gravel layer lies above the shelly sand, separated by a sharp, horizontal boundary. We interpret the c oarse layer to be a storm deposit, which extends across the transect into core 1. Abo ve the storm deposit in core 3, the beach environment continues briefly, then abruptly transitions into an upper bed of finely laminated clays. This might indicate a transition f rom a back lagoonal area to an open water environment and then back to a lagoonal envir onment before becoming an open water area again prior to the construction of the p ower plant. Organics compressed between laminae are dated to 456 + 36 14C yr B.P. Core 1 contains two separate archaeological shell-midden deposits, which may cor relate to the time period in which pale brown sand accumulated in cores 16, 5, and 7. Midden material in core 1 was deposited on dune sand, which correlates with the w hite eolian sand layers in the lower
42 part of core 16, 5, and upper layer of 18. Below t he layers of white sand there is a layer of organic mud or sandy organic mud in both cores 1 8 and 16. These organic layers would be associated with wetland environments. The mottled facies in core 7 may either indicate high bioturbation within the pale brown sa nd layer or human disturbance. When viewing the 1943 aerial photo, it becomes apparent that core 7 is located at or near the former location of Weedon Island Drive. The yellow sand layer in core 18 indicates a vegetated upland or midland environment. It is lik ely that this layer occurs in other core locations, but we did not penetrate to that layer. All cores in this diagram contain a light gray layer at the top indicative of top soil. Fence Diagram C (Figure 11): The lower part of cores 23, 24, and 27 are dominant ly dark yellow reddish-brown metallic sand, similar to that found in core 36, w hich we interpret to represent a westward migrating spring outlet adjacent to this t ransect. Pale brown sand in cores 25 and 26 correlates with the metallic sands in cores 23, 24, and 27. We conclude that the pale brown sand represent the same sediment accumul ation period as the metallic sand. Organic muds in core 23 indicate an adjacent water source Â– possibly a spring and corresponding wetland environment. At that same tim e, a dune ridge was forming across the sites of cores 24-27. As the spring discharge point migrated westward, away from the site of core 23, sand accumulated in the low lying area. Core 24 does not have the light brown sand layer identified at similar levels in co res 23 and 27, possibly due to excavation during road construction. In the upper part of core 23, which lies closest to Riviera Bay, is a muddy organic layer overlying the light brown sand, representing water
43 inundation and possibly mangrove expansion. The up permost bed of light gray-brown sand in core 23 represents eolian accumulation foll owing a drop in water levels or fill associated with nearby mosquito ditch excavation. The first two layers in core 26 may also represent human disturbance due to road constr uction in the early nineteenth century. The mottled white and brown sand in 26, though indi cative of bioturbation, contain little or no organic material, which supports our conclusi on of human disturbance rather than bioturbation. Core 40, taken about 100 meters from shore in the northern portion of Riviera Bay, shows no apparent correlation with the cores taken on land. We conclude that the cores taken from the bay may not be deep e nough to determine past environments, and the sediments may have been affec ted by local dredging of the Bay. Fence Diagram D (Figure 12): The brown highly mottled sand near the base of cor es 9, 29, and 33 suggest a period of vegetation and higher bioturbation. This probably occurred during the period of sediment accumulation, but tap roots may have exten ded downwards from above layers during the later periods as well. The grayish brow n sand found in cores 29 and 33 may have been whiter eolian sand like that found in cor e 30. The once white sands in core 33, possibly more so than core 29 due to its location o n the edge of Boy Scout Lake, may have been altered due to leaching from the above la yers, causing it to become a grayish brown. The yellow sand, possibly indicating a vege tated semiarid or upland environment, in core 9 may have accumulated during the same period as the white and grayish brown sands in cores 29, 33, and 30. Due t o its location on the opposite side of the dune ridge, sediments accumulated at the positi on of core 9 may have, depending on
44 wind direction, had a different source and been mor e protected than the other core locations in Transect D. A protected environment m ay have allowed for more vegetation growth, which is suggested by the higher abundance of roots. The peat and organic rich sandy mud layers, as well as the dark yellow brown layers below, found in cores 33 and 30, may indicate higher water levels in Boy Scout L ake. These higher water levels could have enriched the soils with manganese, accounting for the metallic luster of the dark yellow-brown sands. Higher water may have allowed more vegetation growth around the lakeÂ’s edge, creating the peat and organic-rich san dy-mud layers. The yellow sand seen at the bottom of cores 9 and 30 represent a vegetat ive environment that would have been drier than the preceding environment that created t he darker, more organic rich sediments. All cores within diagram D contain a li ght gray layer at the top indicative of top soil. Fence Diagram E (Figure 13): The white and grayish brown sand layers in cores 38, 22, and 20 are interpreted as eolian dune sand, which may represen t a drier period. Due to the locations of cores 19 and 20 in a lower lying area near wetla nds, more sediment may have accumulated during that time period. The light bro wn sand layers in cores 28 and 21 may have also accumulated at that time, but due to thei r locations on the opposite side of the dune ridge north of Riviera Bay, there may have bee n more vegetation growth or less sand accumulation. Another possible explanation fo r the lack of eolian whitish sand in cores 21 and 28 is that they may have been removed during the construction of Weedon Island Drive. Below these layers of white, grayish -brown, or pale-brown sands, there are
45 layers of organic-rich sandy mud in cores 21, 22, 1 9, and 20. All four cores are in relatively lower lying areas presently adjacent to wetland areas containing mangroves and other wetland indicator vegetation. Core 22 may ha ve been even lower lying during this period of accumulation than core 21. As the wetlan d area dried or shifted, location 22 may have been filled in with sediment before the lo cation around core 21. A yellow sand layer generally lies below both the white sand and organic rich mud. We interpret this layer to be indicative of a vegetated semi-arid loc ation. This layer may also indicate a drier period proceeded by a wetter period which cre ated the organic layers overlaying the yellow sand. Cores 19 and 20 appear to have revers ed layers. The dark yellow-brown metallic sand is interpreted to have been altered t hrough spring-water flow. The spring outlet or pooling location may have migrated from t he location of core 20 to the position of core 19. The area around core 20 was then fille d in by pale brown sediment prior to the layers of white and grayish brown sand. Below the dark yellow-brown sand layer in core 19, there is a pale-brown sand layer. It is u nknown whether core 20 would have penetrated into this layer, had the core been longe r, or if this layer is not present at the location of core 20. Core 38 does show some correl ation with the landward cores in the transect, but due to its location about 100 meters offshore from the northern edge of Riviera Bay, it is unclear whether these are legiti mate correlations or simply represent recent resedimentation associated with channel dred ging. If the lower layers are undisturbed it would appear that this northern area of Riviera Bay was either once dry land during periods of eolian sand movement, or sed iment layers accumulated relatively rapidly in a nearshore marine embayment. The layer containing sand partially cemented with calcium carbonate suggests a dry environment w here secondary CaCO3 was
46 precipitated in the shallow subsoil. Therefore, th e area would have either been wet then dry and then wet again, or it contained water the w hole period, but accumulated sediment rapidly, wind blown or erosion driven, at a fast en ough pace not to be too bioturbated. All cores accept for 38 have either light gray or b rown highly mottled sand indicating a top soil layer. Clay Bed Interpretations Clay sized sediment, concentrated in distinct foun d within cores 04WI3, 04WI4, 04WI11, and 04WI12 is almost entirely calcium carbo nate, with only minor traces of siliclastic grains. This would not have been a sou rce for clay used in the creation of pottery and other clay artifacts found within archa eological deposits on Weedon Island. Possible explanations for the carbonate clay deposi ts include whiting events like those described by Glenn et al. (1995). Conditions for w hiting events in the past may have been more suitable due to past climatic changes inc luding wetter and possibly warmer more tropical conditions as seen in the Soto (2005) and Lake Tulane (Cross et al., 2004; Grimm et al., 1993) studies. Another possible explanation is that the area wher e the carbonate clays formed and accumulated was formerly seaward of the paleosh oreline within a back-barrier microtidal carbonate lagoonal environment, as descr ibed by Nichols (1999). Figure 14 illustrates the location of cores compared with the shoreline prior to power plant construction in the area, which indicates the possi bility of a lagoonal paleoenvironment. That type of environment would have been associated with hypersaline, calm conditions deterring bioturbation and restricting coarse silic iclastic inputs. The barrier islands in
47 that scenario, examples of which are present offsho re of Weedon Island today, may have originated as oyster bars with mangroves colonizing the banks. MangrovesÂ’ associated fauna are known to create calcium carbonate waste t hat could be oxidized creating the light gray color (Brinkman, personal communication, 2006). These back barrier conditions could have also been ideal environments for whitings to occur. The laminations within the carbonate clays are more sug gestive of repeated whiting events, rather than semi-continuous sedimentation that woul d be expected under the mangrove model. It is likely that the paleoenvironments adjacent t o Weedon Island were formerly analogous to that described by Donahue and others ( 2003). According to DonahueÂ’s model, the marine inundation of Tampa Bay began aro und 5,000 yr B.P., and a shallow protected estuarine environment replaced what was p reviously once a freshwater depression. Our cores along the paleoshoreline may preserve a record of the initial encroachment of rising sea-level to a position just high enough to inundate the region of Tampa Bay where Weedon Island is situated. Prior t o the creation of the carbonate clay layers peat layers indicate a wetland environment, although the absence of fossils precludes a freshwater vs. marine interpretation. R adiocarbon ages for the basal sand layer, around 3,600 14C yr B.P. fall at the end of a period of higher rat e of sea-level rise, according to Donahue and others (2003). Donahue et al. (2003) and Wanless (1994) interpret a reduction of the rate of sea-level rise around 3,000 yr B.P., although sea-level has gradually continued to rise since that time. Wright and others (2005) interpreted a slightly lower rate of rise during that period, but all agree that sometime between about 3,000 and 2,500 yr B.P., the rate of sea-level rise decreased considerably compared with
48 the period prior to 5,000 yr B.P.. This slowing in sea level rise allows for mangrove and oyster beds to colonize surfaces and keep up with t he rate of vertical aggradation, resulting in the formation of sand bars and islands in the newly indundated tidal regions. We interpret the 3,600 14C yr B.P. paleoshoreline of Weedon Island to have b een approaching a similar position to that observed in the 1943 aerial image (Figure 14). While it would have been approximately 0-2m meters below present, it would have reached the inner Tampa Bay region. Coastal enviro nments would have been stabilizing, allowing for more long-term human occupation of the coastal zone. These environments allowed for human occupation of the area as the sea level continued to slowly rise and the climate shifted from wetter to drier conditions. Comparison W ith Paleoclimate Records Radiocarbon age estimates on samples taken from the cores appear to match well with both archaeological and paleoclimatic data. C harcoal dated 1453 36 14C yr B.P., collected from midden sediments within core 04WI1, corresponds well with archaeological findings previously reported in the region and recently identified through archaeological reconnaissance on Weedon Island (Wei sman et al., 2005). My interpretations suggest a correlation between th ree radiocarbon-dated sedimentary horizons with wetter and drier periods identified in the speleothem paleoclimate record of Soto (2005). Figure 16 shows the calibrated ages determined in my study compared with Soto (2005) speleothem data and interpreted Little Salt Springs (Alvarez et al., 2005) data compiled and graphed by Van Beynen (2006).
49 Figure 16. The top graph represents oxygen-isotope measurements on speleothems from Briars cave in Florida, and are shown interpreted to repre sent wetter and drier periods (Soto, 2005). The bottom graph is an interpretation of the Little Salt Springs (Alvarez et al., 2005) graph created by Van Beynen (2006). From this figure approximate periods of wet and dry can be associated with core facies associated with dated material. G ray vertical shaded intervals indicate calibrated radiocarbon ages determined from Weedon Island Core s. Horizontal shadings represent interpreted time periods of sediment accumulation. The white shaded region indicates time period of white sand deposition. The yellow shaded region represents the period of yellow and pale brown sand deposition. The black shaded regi on represents the time period of midden deposition My dated samples were taken from a shell midden, a carbonate clay bed, and a sand layer underlying the carbonate clay bed. The oldest sample dated 3600 60 cal yr B.P., within the sand layer below the carbonate cla y, falls within a relatively wet phase.
50 According to our ages, the carbonate formed between 3600 60 and 510 15 cal yr. B.P., which correspond to a relatively long wet per iod. An age of 1350 30 cal yr B.P. determined on charcoal within the midden layer, cor responds with the end of a wet period that preceded a much drier period. Below all of th e midden layers and within many of the other cores a layer of white eolian sand was fo und with very little organic material. This facies may correlate with the drier period aro und 1.3 ka BP. The climate was drier during the period from about 1.75 to 1.3 ka B.P., with a sharp increase in precipitation around 0.9 ka BP, w hich may correlate with shell midden construction and human occupation. In cores 04WI1 and 05WI35 I identified potentially two distinct occupation horizons, represented by se parate midden beds. With so few radiocarbon dated samples, it is difficult to inter pret specific time periods of occupation. It is also possible that the double midden beds rep resent erosion and downslope redeposition, which could be revealed through addit ional radiocarbon dating. With the dates I have one possible explanation, if there are multiple events, which is that the layer of white sand occurring between the midden layers a ccumulated during the drier period around 1.75ka BP. A possible explanation for leavi ng the area at that time might be the lack of fresh water if the drier climate caused the fresh springs in the area to become less active. Other facies within the cores also correlate with the speleothem data. Below the white sand layers within all of the cores, layers o f either yellow sand or organic-rich sand/peat are observed. These facies are interpret ed as forming under vegetation cover. According to the speleothem data, there was a drier period that I associated with the white sand facies. Without further age control, ho wever, these are only speculations.
51 The cores along the paleoshoreline show no obvious indications that sea level was higher than present during the period studied, as s uggested by Stapor et al. (1991). Instead, there appears to be evidence of a continua l rise in sea level, as indicated by Wright et al. (2005). The sediment at the bottom o f the paleoshore cores (04WI3) reflects a vegetated dryland environment much like the facies seen in other more upland cores. Separate layers of peat and intermixed sand which may be interpreted as ephemeral wetlands or could be indicative of mangro ve transgression and regression seen in the Ten Thousand Island area of Florida as the r ate of sea level rise has fluctuated (Donahue et al., 2003). Finely laminated clay laye rs occur directly above these peat layers indicating a possible transition from a shal low shoreline environment to a slightly deeper back lagoonal environment. Sand with interm ixed broken shells in the preceding layer, as well as gravel layers indicating a possib le storm event, show a transition to a beach environment. That type of environment persis ted until the construction of the power plant, and can be viewed in the 1943 aerial p hoto (Figure 14).
52 Conclusion There appears to be some correlation within our cor es and dates taken from our samples to the time periods found in both the paleo climate as well as the archaeological records of the area. Sand layers below the midden layers indicate a drier phase in the climate and suggest that the ancient humans settled on existing dune structures in a region containing freshwater springs and an estuarine food source. According to Weisman et al. (2005), ancient humans occupied the area to some ex tent prior to deposition of the white eolian sand layers. The shell middens, which overl ie the white sand, would have been created at the end of, or following formation of th ese dune ridges. We infer that the indigenous peoples created the middens after sea-le vel had reached near present elevation. The environment at the time would be th at of an estuary ideal for oyster bed creation and other mollusk inhabitation, enabling t he creation of shell middens. We did not find evidence of a higher than present sea leve l, but one that has continued to rise at varying rates. In review of my hypothesis I asked three research questions. After analysis and further interpretation of my data I have made the f ollowing conclusions. How did changes in sea level affect the geomorpholo gy and sedimentation processes of Weedon Island? The paleoshoreline cores show a transition from veg etated soils to wetland environments, to marine environments.
53 What is the relationship between human manipulation of the landscape and the natural sedimentation processes in the geomorphic e volution? Humans appear to have settled on existing dune ridg es and modified and enhanced the topography through the creation of mid den piles. What additional research will be required to assess the anthropogenic and paleoclimate affects on the islandÂ’s geomorphology? Future research is needed to understand the timing of formation of the natural and anthropogenic features on Weedon Island Considerably more radiocarbon dating would assist in the effort to co rrelate facies across core transects, toward the ultimate goal of reconstruct ing relationships between sea-level rise, coastal geomorphology, paleoclimato logy, and the archaeological record.
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57 Poore, R.Z., Dowsett, H.J., Verardo, S., and Quinn, T.M., 2003, Millennialto centuryscale variability in Gulf of Mexico Holocene climat e records: Paleoceanography, v. 18, p. 13, doi: 10.1029/2002PA000868. Robbin, D.M., 1984, A new Holocene sea level curve for the upper Keys and Florida Reef tract, in Gleason, P.J., ed., Environments of South Florida, present and past; II: United States (USA), Miami Geological Society, Cora l Gables, FL, United States (USA), Schmidt, W., 1997, Geomorphology and physiography o f Florida, in Randazzo, A.F. and Jones, D.S., eds., The geology of Florida: United S tates (USA), University Press of Florida, Gainesville, FL, United States (USA), Scott, T.M., 1997, Miocene to Holocene history of F lorida, in Randazzo, A.F. and Jones, D.S., eds., The geology of Florida: United States ( USA), University Press of Florida, Gainesville, FL, United States (USA), Smith, D.L., and Lord, K.M., 1997, Tectonic evoluti on and geophysics of the Florida basement, in Randazzo, A.F. and Jones, D.S., eds., The geology o f Florida: United States (USA), University Press of Florida, Gainesville, FL United States (USA), Soto, L., 2005, Reconstruction of Late Holocene Pre cipitation for Central Florida as Derived from Isotopes in Speleothems [Ph.D. thesis] : Tampa, FL, University of South Florida, p. 1-1-90. Stahl, L.E., 1969, The marine geology of Tampa bay (Florida) [Ph.D. thesis]: United States (USA), Florida State University, Tallahassee FL, United States (USA), Stahle, D.W., and Cleaveland, M. K., Reconstruction and analysis of spring rainfall over the Southeastern U.S. for the past 1000 years: Bull iten of the American Meteorological Society, v. 73, p. 1947-1961. Stapor, F.W.,Jr, Mathews, T.D., and Lindfors-Kearns F.E., 1991, Barrier-island progradation and Holocene sea-level history in Sout hwest Florida: Journal of Coastal Research, v. 7, p. 815-838. Van Beynen, P., 2006, verbal communication: Paleocl imate Conversation. Wanless, H.R., Tedesco, L.P., Cottrell, D., Tagett, M.G., Prospero, J.M.(., and Harwell, C.C.(., 1994, Holocene environmental history of car bonate banks in Florida Bay and
58 Biscayne Bay, south Florida; Symposium on Florida K eys regional ecosystem: Bulletin of Marine Science, v. 54, p. 1087. Watts, W.A., and Stuiver, M., 1980, Late Wisconsin climate of northern Florida and the origin of species-rich deciduous forest: Science, v 210, p. 325-327. Weisman, B.R., Dean, J., O'Brien, M., and Collins, L.D., 2005, Comprehensive Cultural Resource Survey of the Weedon Island Preserve, Pine llas County, Florida: University of South Florida, Report 1, 1-1-401 p. Willey, G.R., 1949, Archaeology of the Florida Gulf Coast: Gainesville, FL, USA, University Press of Florida, p. 100-1-100. Wright, E.E., Hine, A.C., Goodbred, S.L.,Jr, and Lo cker, S.D., 2005, The effect of sealevel and climate change on the development of a mi xed siliciclastic-carbonate, deltaic coastline; Suwannee River, Florida, U.S.A: Journal of Sedimentary Research, v. 75, p. 621-635, doi: 10.2110/jsr.2005.051.
59 Appendix A Core digital Library
60 Site Name: Weedon Island Core length: 154cm Core Sections:2__ Core I.D.: 04WI1 Number of Layers: 7 Compaction: 115cm Date Taken: 3/22/04 UTM Location: UTM-17-0341749E 3082722N I. 0-20 10YR6/3 pale brown very fine single grained sand, medium to many detritus material, abrupt boundary. II. 20-33cm 10YR6/3 pale brown very fine sand w/ very high whole shell and crushed shell content, about 70%, a bone and large root lay vertically near bottom of layer, abrupt boundary. III. 33-45cm 10YR8/6 yellow sand pretty homogenous layer, some darker flecks and mottles, very few shell frags, little to no organics, abrupt boundary. IV. 45-63cm 10YR5/1 gray very fine sand, 90% whole and crushed shells, high organic content in sand, abrupt boundary. V. 63-87cm 10YR7/1 light gray clor gradually gets lighter to a 10YR8/1 white very fine single grained sand abrupt boundary. VI. 87-110cm 10YR8/1 white sand w/ horizontal layers of solid 10YR8/2 very pale brown chunks, possibly reworked limestone or nodules, 3 main horizontal lines of chunks w/ smaller pieces throughout, abrupt boundary. VII. 110-150cm 10YR8/1 white very fine single grainedsand gradually turning 10YR8/2 very pale brown, homogenous layer, no organics.
61 Site Name: Weedon Island Core length: 162cm Core Sections:2__ Core I.D.: 04WI2 Number of Layers: 5 Compaction: 135cm Date Taken: 3/22/04 UTM Location: UTM-17-0341749E 3082722N I. 0-5cm 10YR2/2 very dark brown high organic detritus content, many tiny roots, distinct boundary. II. 5-27cm 10YR4/1 dark gray very fine single grained sand, well mixed medium amount of broken shells and fragments, about 40%, abrupt boundary. III. 27-62cm 10YR4/1 dark gray very fine sand very high large and broken/fragmented shells, highly compacted 90% shells, abrupt boundary. IV. 62-115cm 10YR8/1 white very fine single grained sand, light gray at top gradually getting lighter, few 10YR7/1 white light brown chunks of either reworked limstone or nodules mixed throughout layer, not in distinct layers, semi-distinct boundary. V. 115-162cm 10YR7/1 very pale brown very fine single grained sand, highly mottled at top of layer w/ 10YR6/3 pale brown sand, few mottles continue throughout layer, tiny organic fragments (possibly roots) at top of layer.
62 Site Name: Weedon Island Core length: 269cm Core Sections:3__ Core I.D.: 04WI3 Number of Layers: 11 Compaction: 100cm Date Taken: 4/5/04 UTM Location: UTM-17-0341796E 3082627N I. 0-20cm 10YR7/2 light gray very fine single grained sand, well mixed w/ tiny detritus frags, semi-abrupt boundary. II. 20-72cm 10YR8/2 very pale brown very fine sand, very compacted, circular chunk of clay at 55cm, well mixed tiny shell frags thoughout layer, pretty homogenous, very distinct boundary. III. 72-90cm 5Y8/1 white clay w/ highly laminated layers of 5PB4/1 dark bluish gray and 2.5Y5/4 light olive brown, mainly finely laminated layers of white and bluish clay, very distinct boundary. IV. 90-100cm 10YR8/2 very pale brown very fine sand very well mixed w/ tiny shell frags, abrupt boundary. V. 100-104cm 10YR8/2 very pale brown sand, mainly 90% chunks, possibly reworked limestone or nodules, few shell frags intermixed, abrupt boundary. VI. 104-140cm 10YR8/2 very pale brown highly compacted single grained sand, many tiny well mixed shell frags throughout layer, less at bottom of layer, very distinct boundary. VII. 140-240cm 5Y8/1 white clay highly laminated at top of layer w/ 5PB4/1 dark bluish green clay, from 165-200cm pure white clay w/ very few bluish streaks, from 200-240 highly laminated w/ blue and 5Y7/2 light gray streaks. VIII. 240-245cm 10YR2/1 black highly compacted muddy peat, very distinct boundary. IX. 245-249cm 10YR7/2 light gray very fine single grained sand, no shell frags, homogenous sand, distinct boundary. X. 249-253cm 10YR2/2 very dark brown
63 highly compacted muddy peat, very high flaky root content, very abrupt boundary. XI. 253-257cm 10YR7/2 light gray very fine single grained sand, no shell frags homo. sand, distinct boundary. XII. 257-260cm 10YR2/2 very dark brown highly compacted peat, iron stained near bottom of layer, distinct boundary. XIII. 260-269cm 10YR7/2 light gray very fine sand w/ iron staining.
64 Site Name: Weedon Island Core length: 121cm Core Sections:3__ Core I.D.: 04WI4 Number of Layers: 3 Compaction: 181cm Date Taken: 4/5/04 UTM Location: UTM-17-0341796E 3082627N I. 0-20cm 10YR6/2 light brown gray very fine single grained sand, few well mixed organic and shell frags, distinct boundary. II. 20-70cm 10YR8/2 very pale brown very fine highly compacted sand, medium amount of very tiny well mixed shell frags, tiny streak of clay at 62cm, very distinct boundary. III. 70-82cm 5y8/1 white clay highly laminated w/ 5PB4/1 dark blueish gray and 2.5Y5/4 lihgt olive green clay, very distinct boundary. IV. 82-132cm 10YR8/2 very pale brown very fine highly compacted single grained sand, large and small chunks of reworked limstone or nodules throughout layer, very abrupt boundary. V. 132-179cm 5Y8/1 white clay laminated throughout most of layer w/ 5PB4/1 dark bluish gray and 2.5Y5/4 light olive green clay, little to no laminations from 155-175cm, very abrupt boundary. VI. 179-183cm 10YR2/2 very dark brown highly compacted muddy/peat, orange possible iron stained mottles, very abrupt boundary. VII. 183-187cm 10YR8/2 very pale brown very fine single grained sand, little to no organics, very abrupt boundary. VIII. 187-188cm 10YR2/2 very dark brown highly compacted muddy/peat
65 Site Name: Weedon Island Core length: 260cm Core Sections:2__ Core I.D.: 04WI5 Number of Layers: 4 Compaction: 152cm Date Taken: 4/5/04 UTM Location: UTM-17-0341690E 3082437N I. 0-35cm 10YR6/1 gray very fine single grained sand, high content of detritus at top of layer, well mixed leaf litter and organic matter, gets less towards bottom of layer, gradual boundary. II. 35-112cm 10YR7/4 very pale brown very fine single grained sand, medium sized roots/sticks at top of layer, smaller roots at 60-80cm, organic matter decreases throughout layer 80-112cm pure sand, gradual boundary. III. 112-140cm 10YR8/1 white very fine single grained sand, pure sand w/ medium amount of tiny black phosphate flecks, higher content of flecks from 115-125cm.
66 Site Name: Weedon Island Core length: 121cm Core Sections:3__ Core I.D.: 04WI6 Number of Layers: 3 Compaction: 247cm Date Taken: 4/5/04 UTM Location: UTM-17-0341690E 3082437N I. 0-40cm 10YR6/1 gray very fine single grained sand, high content of detritus at top of layer, large root at 15-22cm, well mixed leaf litter and organic matter gets less toward bottom of layer, gradual boundary. II. 40-110cm 10YR7/4 very pale brown very fine single grained sand, little to no organic matter, very few tiny roots near top of layer and at 65cm, gradual boundary. III. 110-121cm 10YR8/1 white very fine single grained sand, pure sand w/ little to no organic matter, medium to few tiny black phosphate flecks.
67 Site Name: Weedon Island Core length: 260cm Core Sections:2__ Core I.D.: 04WI7 Number of Layers: 4 Compaction: 106cm Date Taken: 4/5/04 UTM Location: UTM-17-0341567E 3082229N I. 0-20cm 10YR6/1 gray very fine single grained sand, very high detritus content, large roots and sticks at top, gradual boundary. II. 20-148cm 10YR6/3 pale brown single grained sand, highly mottled w/ medium root content throughout, mottled w/ white, yellow, brown, black; roots mainly horizontal, looks marbled, semi-abrupt boundary. III. 148-234cm 10YR8/4 very pale brown very fine single grained sand, very few roots/organic matter, one long root from 166-175cm, homogenous pure sand throughout gradually lightening to 10YR8/2 very pale brown, abrupt boundary. IV. 234-260 10YR8/4 very pale brown very fine single grained sand, highly mottled w/ 10YR5/4 yellow brown sand, mottles gradually decrease near end of core.
68 Site Name: Weedon Island Core length: 241cm Core Sections:3__ Core I.D.: 04WI8 Number of Layers: 6 Compaction: 126cm Date Taken: 4/5/04 UTM Location: UTM-17-0341567E 3082229N I. 0-35cm (loss of sed. from 0-15cm) 10YR7/1 light gray very fine single grained sand, high very small root and detritus content, roots decrease at layer boundary, gradual non-distinct boundary. II. 35-80cm 10Yr6/1 gray very fine single grained sand, medium to few flaky root content, highly mottled w/ 10YR8/3 very pale brown, 10YR8/2 very pale brown, and 10YR5/1 gray sand, looks marbled, very distinct boundary. III. 80-100cm 10YR5/3 brown very fine single grained sand, very few flaky roots thoughout layer, few darker and lighter mottles of 10YR5/4 yellow brown and 10Yr7/4 very pale brown, distinct boundary. IV. 100-153cm 10YR5/2 grayish brown very fine single grained sand, high content of medium sized (mangrove) roots and smaller roots, highly mottled and streaked w/ 10YR7/1 light gray, 10YR7/3 very pale brown, and 10YR3/3 dark brown sand, looks marbled, very distinct boundary. V. 153-203cm 10YR7/4 very pale brown very fine single grained sand, dark streak of 10YR4/3 brown sand at 157-159, smaller streaks from 170-176, very few roots/organic matter, pretty homogenous pure sand layer w/ very few tiny flaky roots throughout, sand gradually gets lighter, gradual boundary. VI. 203-241cm 10YR8/2 very pale brown gradually becoming 10YR8/1 white very fine single grained sand, very few small flaky roots throughout layer.
69 Site Name: Weedon Island Core length: 250cm Core Sections:3__ Core I.D.: 04WI9 Number of Layers: 4 Compaction: 119cm Date Taken: 4/5/04 UTM Location: UTM-17-0341497E 3081656N I. 0-39cm 10YR6/2 light brown gray fine single grained sand high to medium content of larger roots (mangrove), and medium to high content (gradually decreasing towards bottom of layer) of tiny roots, sand highly mixed w/ darker and lighter colors, very gradual boundary. II. 39-76cm 10YR7/3 very pale brown fine single grained sand, medium sized roots run down through layer, very gradual boundary. III. 76-140cm 10YR3/6 dark yellow brown very fine single grained sand, long root runs from 76-98cm, little to no other organic matter, mottles of 7.5YR2.5/2 very dark brown, sand gradually gets lighter brown, very gradual boundary. IV. 140-248cm 10YR5/3 brown very fine single grained sand, few 7.5YR2.5/2 mottles near top of layer, very little to no organic matter throughout layer, few tiny dark streaks/mottles from 165-195cm, mostly homogenous pure sand layer, sediment gradually decreases towards end of core.
70 Site Name: Weedon Island Core length: 411cm Core Sections:3__ Core I.D.: 04WI10 Number of Layers: 7 Compaction: 44cm Date Taken: 4/5/04 UTM Location: UTM-17-0341497E 3081656N I. 0-43cm 10 YR7/2 light gray fine single grained sand, medium to high root content, large (mangrove) root chunks at 10cm, 115cm, 30cm, and 42cm, many tiny roots and plant material from 0-30, decreasing after 30cm, color gradually gets darker, gradual boundary. II. 43-91cm 10YR5/3 brown fine single grained sand, medium sized roots (mangrove?) throughout layer gradually becoming less, color gradually turns more yellow, gradual boundary. III. 91-298cm 10YR5/6 yellow brown very fine single grained sand, little to no organic (few roots near top) matter, mostly homogenous sand 153-200cm fine streaks of 10YR3/3 dark brown, distinct boundary. IV. 298-336cm 5YR3/4 dark red brown very fine highly compacted sand, mottles and streaks of 10YR5/6 yellow brown from 305-341, highly compacted chunks of dark (possibly organic) matter from 305-341cm, wavy semi distinct boundary. V. 336-395cm 10YR7/3 very pale brown, medium amount of mottling w/ 5YR3/4 dark red brown, few streaks of plant matter gradually decreasing towards bottom of layer, very distinct boundary. VI. 395-396cm 5YR3/4 dark red brown highly compacted fine sand, very distinct boundary. VII. 395-411cm 10YR6/4 light yellow brown highly compacted very fine sand, broken into chunks, little to no organic matter.
71 Site Name: Weedon Island Core length: 289cm Core Sections:15__ Core I.D.: 04WI12 Number of Layers: 3 Compaction: 58cm Date Taken: 10/30/04 UTM Location: UTM-17-0341818E 3082887N I. 0-20cm 10YR7/1 light gray many medium sized pieces of chert and gravel, abrupt boundary. II. 20-65cm 10YR8/3 very pale brown sand w/ medium amount of tiny shell fragments in horizontal layers, abrupt boundary. III. 65-70cm 10YR7/1 light gray clay, highly horizontally laminated, abrupt boundary. IV. 70-89cm 10YR8/3 very pale brown sand w/ medium amount of tiny shell fragments throughout, clay chunk at 76cm, abrupt boundary. V. 89-92cm 10YR2/1 black highly compacted peat and intermixed sand layers abrupt boundary. VI. 92-95cm 10YR8/3 very pale brown very fine sand w/ medium amount of tiny shell fragments throughout, abrupt boundary. VII. 95-98cm 10YR2/1 balck peat layers intermixed w/ sand layers, abrupt boundary. VIII. 98-112cm 10YR8/3 very pale brown very fine sand w/ medium amount of tiny shell fragments, abrupt boundary. IX. 112-120cm 10YR7/1 light gray clay highly laminated abrupt boundary. X. 120-138cm 10YR8/1 white sand and clay mix some laminations, abrupt boundary. XI. 138-160cm 10YR8/1 whitish clay, somewhat laminated near top, abrupt boundary. XII. 160-181cm 10YR8/1 white sandy clay mix, some laminations abrupt boundary. XIII. 181-211cm 10YR7/1 light gray to whitish and blueish gray pure clay, laminated especially near bottom, abrupt boundary.
72 IXV. 211-248cm 10YR7/2 light gray highly mottled sand, high organic content, many flaky roots, gradual boundary. XV. 248-289cm 10YR7/3 very pale brown very fine sand with few roots running downward through layer.
73 Site Name: Weedon Island Core length: 72cm Core Sections:1__ Core I.D.: 04WI14 Number of Layers: 3 Compaction: 0cm Date Taken: 10/30/04 UTM Location: UTM-17-0341805E 3082849N I. 0-18cm 10YR8/2 very pale brown very fine single grained sand, few well mixed organic materials (hair roots, small sticks, tiny broken shell frags) wavy semi-abrupt boundary. II. 18-58cm 10YR8/3 very pale brown very fine single grained sand, more compacted than top layer, medium to many mottles of 10YR8/1 white sand throughout layer, and from 21-27cm few small (less than 1cm) mottles of 10YR4/4 dark yellow brown clay, and streaks of 10YR4/4 clay at boundary, wavy abrupt boundary. III. 58-72cm 2.5Y8/3 pale yellow clay sand mixture sand is coarser than above layer, large rock at 63-66cm, more sand than clay surrounding rock, clay turns to a 5Y6/2 light olive gray below rock mixed w/ some sand mottles and lighter clay 2.5Y8/3.
74 Site Name: Weedon Island Core length: 255cm Core Sections:2__ Core I.D.: 04WI16 Number of Layers: 5 Compaction: 89cm Date Taken: 10/30/04 UTM Location: UTM-17-0341494E 3082196N I. 0-6cm 10YR8/2 very pale brown fine single grained sand, pretty homogenous, few black 10YR2/1 organic specks and very fine hair roots, very abrupt boundary. II. 6-20cm 10YR2/1 black, compacted sticky organic sandy mud, sand content increases slightly towards end of layer, few very fine hair roots, pretty abrupt wavy boundary. III. 20-184cm 10YR6/3 pale brown fine single grained sand, top of layer has darker organic leaching from above layer until 30cm, medium small roots scattered from top of layer to 100cm, then again at 125cm to bottom of layer, organic wavy streak at 45cm, organic matter w/ rusty appearance from 68-76cm mottling of 10YR8/2 very pale brown sand begins at 150cm and continues to increase to bottom of layer, gradual boundary. IV. 184-254cm 10YR8/1 white very fine single grained sand, few thin roots from 184-195cm, speckles (very small mottles) of 10YR6/3 pale brown sand starting at 220cm to 254cm, mostly homogenous layer of pure white sand, abrupt boundary. V. 254-255cm 10YR2/1 black organic mud possibly more sand below streak, or maybe another layer, end of core.
75 Site Name: Weedon Island Core length: 188cm Core Sections:3__ Core I.D.: 04WI18 Number of Layers: 4 Compaction: 43cm Date Taken: 10/30/04 UTM Location: UTM-17-0341345E 3082048N I. 0-15cm 10YR7/1 light gray very fine single grained sand, medium amount of thin hair roots, roots end abruptly at boundary and sand gradually gets lighter, few black flecks (possibly charcoal) semi gradual boundary. II. 15-73cm 10YR8/1 white very fine single grained pure sand, very little organic matter, a medium sized root at 28-33cm, small very thin plant matter at 42-48cm and 58-61cm, sand begins to darken at 65cm, boundary is semi abrupt w/ somke darkening of sand in layer II. III. 73-107cm 10YR5/2 grayish brown very fine compressed sand, many flaky roots, peety in consistancy, from 90-100cm sand lightens to 10YR8/2 very pale brown and then at boundary begins to darken again to 10YR6/4 light yellow brown, roots gradually decrease but continue into layer IV, semi gradual boundary. IV. 107-299cm 10YR6/4 light yellow brown at top of layer very fine single grained sand, medium sized and medium amount of flaky roots at top of layer, roots gradually decrease until 160cm, from 160-299 little to no organic matter pure sand, one long medium root from 210-260cm, sand lightens slightly to 10YR8/6 from middle of layer towards the bottom 160-250 and then darkens again slightly from 250-299cm w/ very few thin flaky roots.
76 Site Name: Weedon Island Core length: 337cm Core Sections:3__ Core I.D.: 05WI19 Number of Layers: 6 Compaction: 9cm Date Taken: 1/27/05 UTM Location: UTM-17-340579E 3082298N I. 0-8cm light gray 10YR7/1 very fine single graine d sand, medium amount of organic (detritus) material, semi-abrupt boundary. II. 8-15cm 10YR2/2 very dark brown very fine sand, high organic content, large root at 11cm, many smaller flaky roots, abrupt boundary. III. 15-68cm 10YR8/1 white very fine single graine d sand, medium organic, tiny roots throughout layer, abrupt boundary. IV. 68-100cm 10YR2/2 very dark brown very fine sand, high organic decayed content, compacted w/ some flaky roots, sand b/c lighter brown towards bottom of layer, semi-abrupt boundary. V. 100-245cm 10YR3/4 dark yellow brown very fine single grained sand w/ very little organic matter, few flaky roots near top of layer, sand has metallic glimmer, gradual boundary. VI. 245-332cm 10YR8/2 very pale brown very fine single grained sand very few tiny roots.
77 Site Name: Weedon Island Core length: 324cm Core Sections:4__ Core I.D.: 05WI20 Number of Layers: 5 Compaction: 0cm Date Taken: 1/27/05 UTM Location: UTM-17-0340581E 3082281N I. 0-25cm 10Yr6/1 gray very fine single grained sand medium to high well mixed organic matter, many very thin hair roots, wavy, somewhat gradual boundary. II. 25-100cm 10YR7/2 light gray very fine single grained sand, gradual transition to 10YR6/3 pale brown, smaller thin roots from 25-45cm larger roots at 45-65cm in clumps, very few roots from 65-90cm, 90-100 more dense flaky type roots and sediment seems compacted, somewhat like peet at layer boundary, semi gradual boundary. III. 100-155cm 10 YR8/2 very pale brown to 10YR8/1 white very fine single grained sand, high root content throughout layer, larger roots at 118-135cm, all roots flaky, abrupt boundary. IV. 155-200cm 10YR2/1 black compacted very fine sand and organic matter, dark peety layer w/ intermixed roots, pretty homogenous, gradual transition at bottom of layer to 5YR3/4 dark red brown very fine sand, gradually little to no organic matter near bottom, gradual boundary. V. 200-324cm 5YR3/4 dark red brown fine sand, slightly sticky, few roots at 210-220cm, 300-308cm, 310-320cm, sand has metalic glimmer, gradual transition to a lighter 5YR4/6 yellowish red sand, pretty homogenous layer.
78 Site Name: Weedon Island Core length: 224cm Core Sections:2__ Core I.D.: 05WI21 Number of Layers: 4 Compaction: 81cm Date Taken: 2/3/05 UTM Location: UTM-17-0340453E 3082259N I. 0-33cm 10YR7/3 very pale brown coarse single grained sand w/ medium to high organic matter, dark organic peet like streaks at 9-10cm and 19-21cm, amount and size of roots increase towards bottom of layer, and sand b/c slightly finer, straight abrupt boundary. II. 33-51cm 10YR2/1 black very fine compacted single grained sand, high flaky root content, peet like layer, roots lesson near bottom and color gradually lightens, nondistinct gradual boundary. III. 51-96cm 10YR3/4 dark yellow brown very fine single grained sand, medium root content w/ long medium sized roots extending downwards from upper layer, amount of roots lesson near bottom, few at bottom, sand gradually gets lighter, gradual boundary. IV. 96-224cm 10YR6/4 light yellow brown very fine single grained sand at top of layer gradually turning more yellow 10YR6/6 brown yellow at 145-205cm and last 19cm light yellow brown, few small roots at top of layer exstending down from previous layer, medium to large roots at 115-130cm, 160-165cm, and 187-197cm.
79 Site Name: Weedon Island Core length: 325cm Core Sections: __ Core I.D.: 05WI22 Number of Layers: 4 Compaction: 20cm Date Taken: 2/3/05 UTM Location: UTM-17-0340453E 3082259N I. 0-21cm 10YR6/1 gray very fine sand, well mixed, very high root and organic content from 0-10cm, roots mainly small hair-like roots, medium to few roots from 10-21cm and a gradual transition from gray to white sand, boundary gradual. II. 21-105cm 10YR7/1 light gray very fine single grained sand, gradually turning to 10YR8/1 white by 70cm to the end of layer, medium to high root content from 21-65cm, very few roots from 65-105cm, last 5cm (100-105cm) gradual transition to 10YR7/2 light gray sand, gradual boundary. III. 105-158cm 10YR3/3 dark brown very fine sand, high organic matted root matter, roots are medium sized and flaky, very compacted, much like peet, at 140cm begins to b/c less compacted and medium root content, from 140-168cm gradual transition to 10YR6/6 brown yellow sand and fewer roots. IV. 218-325cm 10YR7/6 yellow very fine single grained sand, few medium sized roots like those in layer III near top of layer, 173-190cm 2 long medium sized roots and others at 212-214cm, 235-242cm, and 250-255cm, sand is homogenous and gradually turns slightly lighter 10YR8/4 by the bottom, little to no organic matter after 255cm until last 1cm of core which has medium amount of small roots, few black flecks around 280cm.
80 Site Name: Weedon Island Core length: 335cm Core Sections:3__ Core I.D.: 05WI23 Number of Layers: 6 Compaction: 4cm Date Taken: 2/3/05 UTM Location: UTM-17-0340776E 3082293N I. 0-23cm 10YR7/1 light gray very fine single grained sand, medium amount of well sorted organic matter, clump of roots and sticks from 15-23cm, well sorted layer gradual nondistinct boundary. II. 23-70cm 10YR5/2 grayish brown very fine single grained sand, few to medium amount of organic matter at top of layer gradually increasing to high orgainc (mainly roots) content, large thick roots start at 40cm, small patches of white sand around roots from 55-70cm, abrupt straight boundary. III. 70-80cm 10YR2/1 black sandy mud, very compressed w/ high flaky root content, peaty layer, semi-abrupt boundary. IV. 80-212cm 10YR6/2 light brown gray w/ many streaks and mottles of 10YR2/2 very dark brown at top of layer gradually decreasing and becoming few by 150cm, medium amount of long flaky roots until 150cm, from 160-212cm few organic matter, pure sand, pretty abrupt boundary. V. 212-231cm 10YR2/1 black organic muddy sand layer, few solid roots or organic matter, more sandy than layer III, gradual boundary. VI. 231-335cm 10YR3/6 dark yellow brown very fine single grained sand w/ few to medium amount of roots at top gradually decreasing towards bottom, sand has metallic glimmer at top gradually decreasing, sand gradually b/c lighter to 10YR5/4 yellow brown by bottom, 2 long roots at 285-320cm.
81 Site Name: Weedon Island Core length: 246cm Core Sections:2__ Core I.D.: 05WI24 Number of Layers: 5 Compaction: 81cm Date Taken: 2/3/05 UTM Location: UTM-17-0340838E 3082289N I. 0-13cm 10YR7/2 light gray very fine single grained sand, few to medium amount of broken shells, sticks, roots (organic matter), well mixed sand gradually gets lighter, gradual boundary. II. 13-173cm 10YR8/1 white very fine single grained sand, highly mottled at top of layer w/ 10YR8/2 very pale brown sand and gradually mottling lessons and by 95cm pure white sand, few black phosphate flecks throughout layer, very few organic matter, medium roots at 40-45cm 57-58cm, tiny hair roots at 73cm, large root 90-95cm, no organics from 95cm-163cm, few small flacky roots at 163-173cm, very abrupt straight boundary. III. 173-184cm 10YR2/2 very dark brown very fine single grained sand, darker streaks of 10YR2/1 black throughout layer, slight metallic glimmer, sand gradually gets lighter and more yellowish/red very gradual boundary. IV. 184-245cm 7.5YR3/4 dark brown very fine single grained sand, streakeds of 10YR7/4 very pale brown from 200-207cm, no organic matter, sand gradually lightens to 7.5YR4/6 strong brown, abrupt wavy boundary. V. 245-246cm 10YR6/4 light yellow brown very fine single grained sand.
82 Site Name: Weedon Island Core length: 248cm Core Sections:2__ Core I.D.: 05WI25 Number of Layers: 3 Compaction: 2cm Date Taken: 2/11/05 UTM Location: UTM-17-0341094E 3082358N I. 0-18cm 10YR7/1 light gray very fine single grained sand, few to medium amount of organic matter, few very small roots/sticks/leaves, well mixed, larger medium sized root clump at 8-12cm, wavy semi-abrupt boundary. II. 18-143cm 10YR8/1 white very fine single grained sand many medium (1cm wide) mottles from 18-32cm, pure white homogenous sand afrter 32cm, w/ few well mixed black phosphate particle, one large root at 45cm, one medium root at 75cm, very abrupt wavy boundary. III. 143-248cm 10YR8/4 very pale brown very fine single grained sand, a streak of 10YR6/2 light brown gray sand at top boundary, very small mottles and streaks throughout layer, layer looks spotted, medium to large mottles of 10YR8/1 white sand from 210-220cm, w/ 10YR6/2 surrounding white sand, sand gradually darkens throughout layer to 10YR5/4 yellow brown w/ a streak of 10YR2/2 very dark brown sand in last 1/2cm of core.
83 Site Name: Weedon Island Core length: 254cm Core Sections:2__ Core I.D.: 05WI26 Number of Layers: 6 Compaction: 97cm Date Taken: 2/11/05 UTM Location: UTM-17-0340989E 3082304N I. 0-14cm 10YR6/2 light brown gray very fine sand highly well mixed; medium twigs, leaves, and other organic matter highly bioturbated non-sticky single grained sand abrupt boundary. II. 14-45cm 10YR8/1 white very fine sand, highly mottled w/ 10YR6/2 light brown gray very fine sand, a net or twine rope from about 25-45cm, piece of green glass at 41cm, piece of white chipped rock at about 35cm, layer gradually gets lighter in color, gradual boundary. III. 45-110cm 10YR8/1 white very fine single grained sand, few black phosphate flecks, few mottles near top of layer 45-80cm of 10YR7/1, sand more pure white towards bottom boundary, distinct wavy boundary starting at 110cm and slanting to 124cm. IV. 110-233cm 10YR8/4 very pale brown very fine single grained sand, medium mottling from 110-185cm of 10YR6/3 pale brown sand, small root at 148 and 154cm, long skinny root from 210-215cm, abrupt straight boundary. V. 233-252cm 10YR8/1 white very fine sand, few well mixed black phosphate flecks, very homogenous layer, no organic matter, abrupt straight boundary. VI. 252-254cm 10YR3/2 very dark gray brown very fine, single grained sand.
84 Site Name: Weedon Island Core length: 289cm Core Sections:3__ Core I.D.: 05WI27 Number of Layers: 5 Compaction: 58cm Date Taken: 2/11/05 UTM Location: UTM-17-0340838E 3082281N I. 0-16cm 10YR6/2 light brown gray very fine single grained sand, highly mixed w/ small twigs and other organic matter, gradual boundary. II. 16-73cm 10YR7/4 very pale brown very fine single grained sand, highly mottled w/ 10YR5/2 grayish brown and 10YR8/2 very pale brown sand appears highly disturbed, many tiny hair roots and twigs from 16-40cm, and few towards bottom of layer, larger roots at 45cm, 50cm, and a very thick root at 70cm (appears to be mangrove). III. 73-127cm from 10YR7/1 light gray near top of layer and gradually becomes 10YR8/1 white at bottom of layer, gradual transition, very fine single grained sand few small roots from 73-115cm, no roots in bottom of layer abrupt straight boundary. IV. 127-258cm 10YR5/1 gray gradual transition to 10YR5/6 yellow brown at bottom, many black phosphate flecks and some mixed white sand like layer III near top of layer, gradually ddecreasing, gradual transition tp pure very fine sand, small pieces of organic matter (possibly decomposed root) at 205cm, sand has metalic glimmer especially in second half of layer. V. 258-289cm 10YR6/4 light yellow brown highly mottled and streaked w/ 10YR4/4 dark yellow brown very fine single grained sand, no organic matter.
85 Site Name: Weedon Island Core length: 252cm Core Sections:2__ Core I.D.: 05WI28 Number of Layers: 3 Compaction: 45cm Date Taken: 2/11/05 UTM Location: UTM-17-0340447E 3082342N I. 0-17cm 10YR7/1 light gray very fine single grained sand, very well mixed medium to high orgainc content, many large/medium/small roots and sticks from 11-17cm, first 10cm many very small organic frags, well mixed and homogenous, sand gradually gets browner, gradual non-distinct boundary. II. 17-61cm 10YR7/3 very pale brown very fine single grained sand, highly mottled and streaked w/ 10YR7/1 light gray sand from 17-40cm, and highly mottled w/ 10YR8/4 very pale brown sand, 10YR8/6 yellow sand and 10YR7/1 light gray sand, appears marbled, medium to high root content from 17-30cm w/ medium and small sized roots, few small roots, abrupt straight boundary, one large root from 55-65 through boundary. III. 61-252cm 10YR8/6 yellow very fine single grained sand, medium to few orgainc root content from 61-140cm long roots from 130-140cm, scattered smaller roots from 61-130cm, mottling of 10YR6/6 brown yellow and 10YR7/3 very pale brown from 61-77cm, w/ a streak at 70-75cm, one long medium sized root from 181-194, sand gradually gets lighter thoughout layer becoming 10YR8/4 very pale brown at bottom, few mottles of 10YR7/2 light gray from 200-220cm, one large mottle of 10YR6/4 from 250-252cm, mostly pure homogenous sand from 140-252cm.
86 Site Name: Weedon Island Core length: 230cm Core Sections:2__ Core I.D.: 05WI29 Number of Layers: 4 Compaction: 38cm Date Taken: 2/17/05 UTM Location: UTM-17-0341551E 3081883N I. 0-30cm 10YR7/1 light gray very fine single grain ed sand, very high organic content, many small medium sized roots from 5-15cm, smaller broken organic matter in first 5cm, roots and sticks throughout layer, sand gradually gets lighter, very gradual boundary. II. 30-157cm 10YR7/2 light gray very fine single grained sand, very high amount of medium sized roots thoughout rest of layer, many 10YR8/1 white mottles from 50-70cm making a marbled appearance, white sand seems to have mixed into layer from 70-157 giving a frosted appearance, semi abrupt wavy boundary. III. 157-205cm 10YR3/2 very dark gray brown very fine single grained sand, from 157-180cm many small mottles of 10YR7/2 light gray sand, mottles gradually decrease, medium root from 157-163cm, 172-176cm, and 180-190cm, sand gradually lightens after 195cm, sand has frosty appearance throughout layer, very gradual boundary. IV. 205-230cm 10YR5/3 brown very fine single grained sand, medium root at 205-207cm, 210cm, and 220cm, few roots compared to above layers, sand appears frosted.
87 Site Name: Weedon Island Core length: 299cm Core Sections:3__ Core I.D.: 05WI30 Number of Layers: 5 Compaction: 38cm Date Taken: 2/17/05 UTM Location: UTM-17-0342022E 3082103N I. 0-35cm 10YR5/1 gray fine single grained sand, high content of leaf litter, and organic matter from 0-10cm, few from 10-25cm, 25-35cm medium amount of medium sized roots, sand gradually gets lighter, gradual boundary. II. 35-86cm 10YR7/1 light gray to 10YR8/1 white very fine single grained sand, few very small roots from 35-45cm and one large root at 40-45cm, very few to no organic matter and fine roots throughout rest of layer, pretty homogenous pure white sand, very abrupt straight boundary. III. 86-108cm 10YR3/3 dark brown very fine compacted single grained sand and organic matter, medium to many flaky roots and organic matter, somewhat peety layer, homogenous, abrupt straight boundary. IV. 108-145cm 5YR4/6 yellowish red fine single grained sand, sand has metallic glimmer, few decomposing larger roots at 110cm and 125-135cm, few medium sized roots from 135-145cm, sand gradually gets lighter, gradual boundary. V. 145-299cm 10YR6/4 light yellow brown very fine single grained sand gradually lightening to 10YR7/3 very pale brown sand by 195cm, medium amount of medium sized roots running downward throughout layer, pretty homogenous layer.
88 Site Name: Weedon Island Core length: 225cm Core Sections:2__ Core I.D.: 05WI31 Number of Layers: 5 Compaction: 67cm Date Taken: 2/17/05 UTM Location: UTM-17-0341805E 3081791N I. 0-20cm 10YR2/1 black organic mud, very small sand content, 0-10cm 80% small to medium roots, few larger roots at 10cm, 10-20cm more compact mud and less roots, very abrupt boundary. II. 20-74cm 10YR7/2 light gray very fine single grained sand, few to medium mottles of 10YR2/1 black sandy mud throughout, few medium sized roots at 25cm, 32-35cm, and 55-60cm, sand gradually gets lighter brown to 10YR8/2 very pale brown, abrupt wavy boundary. III. 74-77cm 10YR2/2 very dark brown very fine sand, feels slightly muddy, pure muddy homogenous sand, abrupt boundary. IV. 77-200cm 10YR4/4 dark yellow brown very fine single grained sand, medium amount of long stem roots running downward throughout layer, sand gradually gets lighter 10YR5/4 yellow brown nea boudary, very gradual boundary. V. 200-225cm 10YR8/3 very pale brown very fine single grained sand, gradually turning lighter 10YR8/2 very pale brown by end of core, very few organic matter, few medium roots at 205-207cm and 224cm.
89 Site Name: Weedon Island Core length: 257cm Core Sections:2__ Core I.D.: 05WI32 Number of Layers: 7 Compaction: 24cm Date Taken: 2/17/05 UTM Location: UTM-17-0341691E 3081812N I. 0-10cm 10YR3/1 very dark gray very fine sand w/ high orgainc content, well mixed homogenous layer w/ many small roots throughout, somewhat sticky and compacted, sand gets slightly lighter, semi-abrupt boundary. II. 10-97cm 10YR7/1 light gray very fine single gr ained sand, medium organic content smaller flaky roots from 10-40cm then roots become slightly larger, one medium to large sized root from 30-33cm, longer medium sized flaky roots from 65-97cm, sand gradually gets lighter after 35cm turning 10YR8/2 very pale brown, mottled and streaked w/ 10YR7/3 very pale brown, looks marbled, very abrupt boundary. III. 97-105cm 10YR2/1 black mudy sand, 2 long root s stretching through layer running from above layer through to the layer below, few flaky roots at bottom of layer, abrupt boundary. IV. 105-120cm 10YR5/3 brown very fine single grain ed sand, few black 10YR2/1 long streaks, one long medium sized root running down from above layer, abrupt boundary. V. 120-123cm 10YR2/1 black muddy sand, homogenous, abrupt boundary. VI. 123-201cm 10YR3/2 very dark gray brown near to p of layer gradually lightening to 10YR6/4 lighter yellow brown, medium amount of medium sized roots from top of layer to 165cm, black 10YR2/1 mottling and streaking until 140cm, sand has frosted appearance, gradual boundary. VII. 201-257cm 7.5YR4/4 brown very fine single grained sand, metallic or frosty appearance, few streaks and mottles of 7.5YR2.5/3 very dark brown, streak at 234-236cm.
90 Site Name: Weedon Island Core length: 188cm Core Sections:2__ Core I.D.: 05WI33 Number of Layers: 6 Compaction: 115cm Date Taken: 2/17/05 UTM Location: UTM-17-0341622E 3081905N I. 0-12cm 10YR5/1 gray very fine single grained sand, well mixed, high organic content (roots, leaves, sticks), abrupt straight boundary. II. 12-35cm 10YR2/1 black organic mud mottles w/ 10YR6/2 light brown gray fine sand, many large mangroves roots at 15-23cm, broken mollusk shell at 24-25cm, mottling increases towards bottom of layer abrupt straight boundary. III. 35-100cm 10YR6/2 light brown gray, turning lighter towards bottom, fine single grained sand w/ many streaks and mottles of 10YR2/1 black organic mud 1-2mm thick, w/ few tiny root hairs w/in mud, streaks from 40-50cm then becomes more mottled from 50-84cm then one thick streak at 84-90cm of 10YR2/1 black organic mud w/ few tiny hair roots, then sandy and mottled again, root pieces at 49cm and 62cm, abrupt boundary. IV. 100-116cm 10YR4/4 dark yellow brown very fine sand, single grained, streaked w/ a mottle of 10YR8/1 white sand at 108-110cm, mixed streaks of 10YR8/1 white and 10YR2/1 black organic mud, layer appears somewhat mixed and bioturbated, abrupt pretty straight boundary. V. 116-165cm 10YR5/6 yellow brown fine sand, slightly sticky, few black 10YR8/1 organic mottles from 116-150cm, sand gradually lightens to
91 10YR6/4 light yellow brown at bottom of layer. VI. 165-185cm 10YR5/3 brown very fine sand, very mottled w/ 10YR6/4 light yellow brown sand and one big mottle of 10YR5/6 yellow brown sand at top boundary from 165-168cm
92 Site Name: Weedon Island Core length: 170cm Core Section:2__ Core I.D.: 05WI34 Number of layers: 5 Compaction: 161.5cm Date Taken: 2/24/05 UTM Location: 17-0341204E 3082756N I. 0-25cm 10YR4/1 dark gray homogeneous oxidized sand, clear quartz grains, loose single grained, with few to common fine rootlets and charcoal flecks, few medium oak roots near base, few scattered small shell fragments in lower 10cm (oyster lighting whelk), clear wavy boundary. II. 25-48cm 10YR3/2 very dark grayish brown slightly organic fine sand, clear quartz grains, few fine dark grayish mottles, loose, single grained to weakly granular structure, 30% of matrix is shells (eastern oyster, crown conch, lightning whelk, moonsnail), some animal bone fragments, few fine roots at top, few fine charcoal flecks, clear wavy boundary. III. 45-59cm 10YR4/2 dark grayish brown becoming 10YR5/2 grayish brown fine sand, loose, single grained to weakly granular structure, trace amount of shell (moonsnail and oyster fragments), few fine roots, clear quartz grains, irregular boundary, possible root/bioturbation, few fine pale brown mottles, with midden organics and shells and leaching from zone II. IV. 58-134cm 10YR7/4 very brown to 10YR7/6 yellow fine sand, loose, single grained, 58-80cm bioturbated with 10YR5/3 brown and 10YR6/3 pale brown mottles and common roots, yellow sand has a few medium roots at 105 and 115-132cm, faint charcoal impressions, clear smooth boundary, yellow qurtz grains mixed with clear. V. 134-170cm 10YR7/3 becoming 10YR8/2 very pale brown fine sand, loose, single grained, fairly homogeneous, few root fragments at 150-165cm, mixture of clear patinated quartz 134-140cm, below is clear quartz.
93 Site Name: Weedon Island Core length: 208cm Core Sections:2__ Core I.D.: 05WI35 Number of layers: 6 Compaction: 97cm Date Taken: 2/24/05 UTM Location: 17-0341219E 3082744N I. 0-23cm 10YR5/2 grayish brown very fine sand, medium amount of small shell fragments evenly interspersed in layer, very small root and organic matter, homogeneous layer, abrupt boundary. II. 23-54cm 10YR5/2-10YR4/2 grayish brown to dark grayish brown very fine sand, large mullusk shells and fragments surrounded by sand large root at 25-30cm and 43-47cm abrupt shell boundary. III. 54-65cm 10YR6/4 light yellow brown very fine sand, no shells and only very few small roots and organic matter, upper part wavy boundary with darker sand but no shells, abrupt bottom boundary, homogeneous sand layer. IV. 65-88cm 2.5Y2.5/1 black to 10YR5/1 gray, mostly large shells and shell fragments intermixed with some sand, top part very dark black sand surrounding shells, sand and shells get lighter towards bottom, mixture of shells, mainly oysters, abrupt lower boundary. V. 88-102cm 10YR6/2 light brown gray very fine sand, very few shell fragments, one small gastropod at 91cm, some roots and shell fragments at 98-102cm mostly homogeneous layer, wavy bottom boundary. VI. 102-208cm 10YR8/6 yellow fine sand, top boundary wavy with 10YR6/2 gray sand extending down in places to 114cm, small stringy roots at 149-157cm and scattered in small amounts in layer, pretty homogeneous with a few small white chunks, larger root at 126cm, sand seems well packed with some harder chunks, color gets slightly lighter at bottom gradually.
94 Site Name: Weedon Island Core length: 319cm Core Sections:4__ Core I.D.: 05WI36 Number of layers: 5 Compaction: 21.5cm Date Taken: 2/24/05 UTM Location: 17-0341221E 3082685N I. 0-22cm. 10yr7/1 light gray, very fine grained sand, organic leafs and roots throughout, decreasing towards end of section. Flecks of charcoal present, transition is gradual and mottled. II. 22-74cm. 10YR8/1 white very fine sand, mottled with 10YR7/1 light gray very fine sand towards top of section, larger roots and organic matter from 22cm-42cm, smaller bits speckled throughout, lower boundary gradual with darker sediment intermixed from 70-74cm. III. 74-118cm. 10YR3/4 dark yellow brown very fine sand, a few thin roots near top of layer, from 94-118cm, many long thin roots as well as thicker roots and organics from 108-119cm, gradual color change to lighter yellow brown near bottom of layer, gradual transition. IV. 118-182cm. 10YR8/4 very pale brown very fine sand, starts out darker at top of layer and transitions to very pale brown and then begins to get darker again. Medium amount of root matter from 118-146cm, larger root at 140-146cm, then a few small root and darker organic matter from 146-182cm, very gradual transition to darker metalic brown looking sand. V. 182-319cm. 10YR4/6-10YR3/6 dark brown very fine sand, lighter at top of layer and gradually darker, long dark roots from 185-198, and 208-223, and a large root chunk at 244-248cm (collected for dating), very few other small roots and organics mixed in, sand has metalic glimmer.
95 Site Name: Weedon Island Core length: 234cm Core Sections:3__ Core I.D.: 05WI37 Number of Layers: 7 Compaction: 60cm Date Taken: 2/24/05 UTM Location: UTM-17-0341063E 3082734N I. 0-27cm 10YR7/1 light gray very fine single grained sand, well mixed w/ very fine roots and flecks of organic matter, medium sized root at 12cm, few flaky roots near end of layer, abrupt straight boundary. II. 27-49cm 10YR4/3 brown very fine sandy peat like layer, very compacted w/ many flaky roots and organic flecks, very abrupt boundary. III. 49-72cm 10YR3/1 very dark gray, organic sand, very high content (90%) shells (oysters mainly), abrupt end of shells at 72cm. IV. 72-89cm 10YR3/1 very dark gray very fine sand, very compacted some what peat like w/ some flaky roots, small chunks of 10YR8/6 yellow sand mixed in, homogenous layer, abrupt boundary. Sediment lost from 89-115cm. V. 89-129cm 10YR4/1 dark gray very fine single grained sand w/ some very small mottles of 10YR2/1 black sand, few flaky roots at bootom of layer, semi gradual boundary. VI. 129-157cm 10YR2/2 very dark brown very fine sandy peat, highly compacted especially middle of layer, w/ flaky roots, semi gradual boundary as sand becomes less compacted and lighter in color. VII. 157-234 10YR7/3 very pale brown very fine single grained sand, long tap roots starting at top of layer running down to 205cm, smaller root chunks from 205-234cm, sand gets gradually lighter from 10YR5/3 brown at top to 10YR8/3 very pale brown at bottom.
96 Site Name: Weedon Island Core length: 504cm Core Sections:6__ Core I.D.: 05WI38 Number of Layers: 6 Compaction: 70cm Date Taken: 5/10/05 UTM Location: UTM17-0340400E 3082184N I. 0-38cm 10YR6/1 gray, dries to 10YR7/1 light gray, fairly homogeneous fine sand, moist, very fine clear quartz, some silt; few scattered clam valves and fragments, one has drill hole at 34cmbs, 1 root frag at 32cmbs, clear smooth boundary; few scattered phosphate particles. II. 38-228cm 10YR6/2 light browniosh gray fine sand dries to 10YR7/1 to b7/2 light gray sand, has marble appearance w/ 10YR3/2 many, medium to fine very dark grayish brown, organic or organic coated quartz in thin streaks and rounded mottles, mnay mottles or streaks of 10YR5/2 grayish brown sand, has sulfer smell, base is slighly scoured w/ blotch of organic mud, clear quartz throughout. III. 228-287cm 2.5Y8/1 white very fine sorted; homogeneous, well sorted; few medium 10YR6/2 light brownish gray mottles and small organic streaks in upper 15cm, boundary is clear wavy; clear quartz grains, few black phosphate particles. IV. 287-381cm 10YR7/3 very pale brown to 10YR7/2 light gray moist fine silty sand w/ some clay, dries to 10YR7/2, common medium mottles of white fine sand (zone III color) throughout, clear abrupt
97 boundary, clear quartz grains. V. 381-384cm 2.5Y8/1 white fine sand w/ clear quartz sand grains, few phosphate particles scattered, similar to zone III, clear abrupt boundary. VI. 384-504cm 2.5Y7/1 light gray silty sand w/ faint very thin 1-2cm streaks of 2.5Y6/1 to 7/1 organic mud, or sandy clay, common medium mottles of light gray to light brownish gray silty sand and white sand, at 480-484cm 7.5YR6/3 light brown streaks w/ silty sand.
98 Site Name: Weedon Island Core length: 434cm Core Sections:5__ Core I.D.: 05WI39 Number of Layers: 6 Compaction: 143cm Date Taken: 5/10/05 UTM Location: 17-0341458E 3081533N I. 0-39cm 10YR6/1 gray fine moist sand, dries to 10YR7/1, fairly homogenous, few fine organic mottles in lower half, very fine clear quartz, some silt, very few shell fragments diffuse boundary. II. 39-238cm 10YR6/2 light brownish gray fine sand, and 10YR4/1 dark grayish brown organic matter or organic coated quartz, in thin streaks or rounded mottles, many mottles of 10YR5/2 grayish brown sand, has sulfer smell, scoure4d boundary, dark organic mottles and streaks start at 52cm and continues to140cm w/ fewer above and below that area. III. 238-276cm 2.5Y7/1 light gray fine sand, well sorted few organic streaks from zone II, diffuse gradual boundary, few scattered black phosphate particles; clear quartz sand. IV. 276-293cm 10YR6/3 pale brown or 2.5Y6/3 light yellowish brown silty sand dries to 10YR6/2 light brownish gray, gradually grades to 10YR7/2 light gray color below 290cm, diffuse gradual boundary, clear quartz sand. V. 293-414cm 2.5Y7/1 light gray fine sand, w/ some silt near upper 30-50cm of zone, dries to 2.5Y8/1 white sand, few scattered phosphate, clear wavy boundary, few organic streaks of 10YR5/2,
99 clear quartz. VI. 414-434cm 2.5Y7/1 light gray silty sand w/ faint very thin 1-3mm streaks of 2.5Y6/1 to 7/1 organic mud or clay throughout, common medium mottles of light gray to light brownish gray silty sand and white sand, clear quartz.
100 Site Name: Weedon Island Core length: 418cm Core Sections:5__ Core I.D.: 05WI40 Number of Layers: 7 Compaction: 69cm Date Taken: 5/10/05 UTM Location: UTM-17-0340773E 3082232N I. 0-31cm 10YR8/2 pale brown fine wellsorted sand, homogenous, very few dark gray 10YR4/1 mottles, boundary gradual, very few shell frags. II. 31-148cm 10YR8/2 pale brown fine well-sorted sand, mottles increase to many giving a marble appearance, darker mottles 10YR3/2 very dark gray brown, few tiny shell frags throughout, larger bivalve half shell at 130cm, bark or wood fragment at boundary, wavy boundary. III. 148-214 10YR6/2 light brown gray, large black 10YR2/1 mottle at top of layer, mottles of 10YR5/4 yellow brown starting around 160cm very few tiny shell frags, mottling becomes lighter towards gradual boundary, sand begins to become cemented as it dries, very sticky when wet, at end of layer. IV. 214-232 10YR8/3 very pale brown sticky sand w/ many 10YR8/1 white mottles, no shells, completely cemented when dry, large dark mottle, or decomposed root mark at layer boundary. V. 232-305cm 10YR8/3 very pale brown sticky sand w/ few mottles, mottles are more horizontal laminations (less mixed) of 10YR8/1 white sand, few thin darker laminations, completely cemented when dry, laminations
101 begin to end around 280cm. VI. 305-318cm 10YR8/1 white sticky sand w/ medium mottles of 10YR8/3, cemented completely, abrupt wavy boundary from 316-220cm. VII. 318-418cm 10YR8/3 very fine sticky sand, cemented as dries, w/ few to medium 10YR8/1 white laminations and mottles.