Speleogenesis

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Speleogenesis

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Speleogenesis
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Speleogenesis
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Klimchouk, Alexander B. (Aleksandr Borisovich)
Ukrainian Institute of Speleology and Karstology
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No. 11 (2011)

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Issue 11, 2011Speleogenesisand Evolution of Karst Aquifersonline scienti c journal www.journal.speleogenesis.info/journal/ The Prichernomorsky (Black Sea) artesian basinThe Prichernomorsky artesian basin is a major hydrogeological structure of the north Black Sea region, occupying the south of the continental part of Ukraine and the north-central plain part of the Crimea Peninsula (Fig. 1). It roughly corresponds to the Prichernomorsky tectonic depression developed during Cretaceous-Paleogene on the Arhean-Mesoproterozoic basement of the Eastern-European Platform (within the continent) and the neoproterozoic-Early Triassic basement of the Scythian Plate (within the Crimea Peninsula). The upper part of the sedimentary cover is comprised by the Neogene (lower Pliocene through uppermiddle Miocene) sequence of intercalated limestones, sands, clays and marls. The sequence lays on Paleogene (Eocene through Paleocene) and Cretaceous carbonate and clay deposits. The Neogene sequence hosts an extensive multistory aquifer system, with aquifers in limestones and sands separated by leaky aquicludes comprised by clays and marls (Lushchik, Lisichenko, Yakovlev, 1988). Subaerial clays of Pliocene age form the upper con ning unit. The con ning cover and the upper aquifer units are incised by erosion and partially drained throughout the large part of the basin (Fig. 1A). Aquifers in carbonate members of the Paleogene and Cretaceous succession are less extensive and overall con ned except of the southern edge of the basin. In the southern edge in Hypogene speleogenesis in the Cenozoic carbonates of the Prichernomorsky artesian basin (north Black Sea region)A.B. Klimchouk1*, E.I. Timokhina1 and G.N.Amelichev1This article is an extended abstract of the paper presented at the International Conference on Karst Hydrogeology and Ecosystems (8-11 June 2011, Bowling Green, Kentucky) and the 3rd Middle-East Speleology Symposium (23-35 Sept. 2011, Beirut, Lebanon)1 Ukrainian Institute of Speleology and Karstology, 4 Vernadsky Prospect, Simferopol, Ukraine orresponding author: e-mail: klim@speleogenesis.info by the authors. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license Klimchouk, A.B., Timokhina, E.I., Amelichev, G.N. 2011. Hypogene speleogenesis in the Cenozoic carbonates of the Prichernomorsky artesian basin (north Black Sea region). Speleogenesis & Evolution of Karst Aquifers 11, 48-51 ( http://www.speleogenesis.info/content/ )Abstract: This paper demonstrates the dominant hypogenic origin of caves and other karst features in the Prichernomorsky artesian basin, a major hydrogeological structure of the north Black Sea region. The basin occupies the south of the continenta l part of Ukraine and the north-central plain part of the Crimea Peninsula and is dominated by the Neogene (lower Pliocene throug h upper-middle Miocene) and Paleogene (Eocene through Paleocene) carbonate rocks, intercalated with sands, sandstones, clays and marls. The key study areas, in which some limestone members are exposed and partially drained, lie in the opposed sides of the basin: the north Black Sea region in the continental part (caves in lower Pliocene and Miocene limestones) and the Inner Range of the fore-mountain Crimea in the south, where the basin borders with the fold-trust Alpine mountain region (caves in Eocene and Paleocene limestones). The hypogenic origin of caves is strongly suggested by the analysis of cave morphology and occurrence relative to lithostratigraphy and structural features, cave sediments, isotopic and mineralogical dat a, and paleohydrogeological analysis. Despite of differences in age and diagenetic maturity of the host rocks, the caves demonstra te remarkable common features imposed by their common origin. The hypogenic speleogenetic model well explains observed speci c hydrogeological and geochemical features of the regional multi-storey aquifer system in the central con ned part of the basin. Hypogene speleogenesis is likely to play a role in the formation of carbonate-hosted reservoirs, as well as in the migra tion and accumulation of hydrocarbons in the Prichernomorsky basin. Keywords: Karst, Hypogene speleogenesis, Black Sea Basin, Ukraine.

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49Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 online scienti c journal www.journal.speleogenesis.info/journal/Klimchouk A.B. et alHYPOGENE SPELEOGENESIS IN THE CENOZOIC CARBONATES OF THE PRICHERNOMORSKY ARTESIAN BASINCrimea, the basin borders with the Crimean Mountains (the Alpine fold-thrust region) and encompasses the cuesta-like Outer and Inner Ranges of the Crimean fore-mountains (Fig. 1B). Along the Inner Range, the Neogene rocks are eroded away and Paleocene and Eocene limestones are uplifted and tilted at 5-20 degrees, forming a northwest-dipping monocline and southeast-facing cuesta scarps. Karst features occur in Pontian (Early Zanclean), Meotian (Late Messinian) and Sarmatian (Early Messinian) limestones of the Neogene system. In Paleocene and Eocene limestones, deep-seated cavities and karsti ed zones are known from borehole data in the Plain Crimea part of the basin. In the fore-mountain Crimea, accessible caves, karsti ed fractures, numerous grottoes and clusters (zones) of cavernosity in these limestones are abundantly displayed in the cuesta scarps of the Inner Range. Karst in the region has been previously interpreted in the framework of the traditional epigenic paradigm, with deepseated features being regarded as paleokarst. Recent studies, however, strongly suggest that hypogene speleogenesis is the region-wide process responsible for the formation of conduits, caves and cavernous zones, presently relict in the areas where limestones are uplifted and drained, and still developing in the con ned areas.Odessa Region: Karst in lower Pliocene Limestones The most instructive type area for studying speleogenesis in the Pontian limestones is the Odessa city in the south of the continental Ukraine (see Fig. 1, A for location), where extensive ancient underground mines (locally called ‘catacombs’) intercept numerous karst caves and karsti ed fractures. 68 intercepted caves with total length of about 7,150 m are documented there, including 7 caves with individual lengths of over 300 m and two caves longer than 1 km (Pronin, 2009). The most outstanding features of these caves are their complete lateral isolation and apparent irrelevance to the surface (Fig. 2), which rules out any possibility of their formation by lateral ow and surface recharge. Caves are fracture-controlled, single linear passages, or clusters of intersecting passages, blind-ended in every lateral direction. The analysis of cave morphology and sediments (Klimchouk, Pronin & Timokhina, 2010) has rmly established that the caves had been formed under shallow leaky con ned conditions by waters rising across the Pontian limestones from deeper aquifers and mixing with lateral shallow ow along certain beds, which caused renewal of the aggressiveness. Similar caves are known in the south-west of Ukraine and Moldova where the Pontian and Sarmatian limestones are incised by erosional valleys.The Fore-Mountain Crimea: Karst in Eocene and Paleocene LimestonesThe type area for studying origins of solution porosity in the Eocene and Paleocene limestones is the Inner Range of foremountain Crimea in the southern edge of the basin, where these limestone beds form distinct cuestas (Fig. 1B). Recent studies have revealed ample and systematic evidences that caves are of hypogenic origin, and that most of solution features in the scarps are remnants of morphologies of caves and karsti ed Fig. 1. A Hypogene caves and relevant hydrogeologic features in carbonate successions in the Prichernomorsky artesian basin, South Ukraine. Major tectonic structures (circled characters): A Eastern-European Platform (pre-Rifean); B Scythian Plate (epi-Paleozoic); C North Dobrogea fold-thrust region (Hercynian); D Crimean foulded region (Kimmerian-Alpine); E Crimean foredeep (Kimmerian-Alpine). Other tectonic structures: 1 Ukrainian Shield; 2 Dnieper-Donetzk Depression (Mesozoic); 3 Prichernomorsky Depression (Cretaceous-Paleogene); 4 Central-Crimean Uplift (Cretaceous-Paleogene). B – Geologic map of the southwest part of the Crimean Peninsula and schematic geologic pro le (after Yudin, 2008).

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Klimchouk A.B. et al 50online scienti c journal www.journal.speleogenesis.info/journal/ Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011HYPOGENE SPELEOGENESIS IN THE CENOZOIC CARBONATES OF THE PRICHERNOMORSKY ARTESIAN BASINfractures, the walls of which are now exposed due to block-fall retreat of the scarp faces (Klimchouk, Timokhina & Amelichev, 2009). The solution features in various beds demonstrate strong lithostratigraphic control in their distribution and are vertically stacked into transverse complexes (Fig. 3). Caves are fracturecontrolled, linear, or crude maze clusters, demonstrating the complete suite of speleomorphs indicative of hypogenic origin (Klimchouk, 2007). Isolated cavities, observed in the contemporary scarps as grottoes and niches, as well as zones of spongework porosity (cavernous zones), develop where laterally conductive beds of high initial porosity are crossed by penetrating vertical fractures that once conducted rising uids from a regional ow system (Fig. 4A). Large linear faultrelated rift-type conduits in the underlying Upper Cretaceous marls, that served as feeding ‘roots’ for hypogenic caves in the limestones above, have been recently documented in the foot of some cuestas. Besides the cave morphology, the hypogenic origin of the caves is corroborated by the isotope alteration halo in the host rocks (Dublyansky et al., 2011) and by recent nding of a massive crust of phreatic columnar calcite and a hydrothermal mineral stibnite in some caves. The abundance, outstanding expression, preservation and accessibility of relict hypogene karst features in the extensive cuesta exposures of the Inner Range makes the latter a foremost region for studying regularities of hypogene solution porosity development, the process currently ongoing in the adjacent artesian basin of the Plain Crimea.Concluding remarksRegional cave studies and analysis of hydrogeological and geochemical features of the regional aquifer system throughout the basin (Fig. 1A) reveal the basin-wide role of hypogene speleogenetic processes in the development of solution porosity and permeability in carbonate rocks. In spite of some distinctions imposed by tectonic position and local structural features, hypogene caves in limestones of different age and of Fig. 3. Conditions of the formation (A) and the current geomorphic situation (B) of caves and other karst features in the Inner Range of the Crimea fore-mountains. Fig. 2. Distribution of caves (red lines) intercepted by ancient mines (grey lines) in the Pontian (lower Pliocene) limestones in the Odessa region, south Ukraine (modi ed after Pronin, 2009).

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51Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 online scienti c journal www.journal.speleogenesis.info/journal/Klimchouk A.B. et alHYPOGENE SPELEOGENESIS IN THE CENOZOIC CARBONATES OF THE PRICHERNOMORSKY ARTESIAN BASINdifferent degree of diagenetic maturity and pre-speleogenetic matrix porosity, have some remarkable common features in occurrence and morphology. The main speleogenetic process, clearly discerned from hydrostratigraphic/ structural relations and morphology of caves, is renewal of aggressiveness due to mixing of deep vertical and shallow lateral ow in the con ned aquifer system (Fig. 4). Dissolution by rising thermal waters Fig. 4. Conceptual models of the speleogenetic effects of dissolution due to mixing of the upwelling deep ow along a sub-vertical fracture conduits with shallower lateral ow along beds of high pore matrix permeability. A Formation of cavernous zones and isolated cavities, B Symmetric (2) and assymmetric (3) widening of an original fracture conduit (1) along the bed of high matrix porosity and permeability.and by sulfuric acid (due to oxidation of H2S) is also likely to play a role, at least locally. The Plain Crimea part of the Prichernomorsky artesian basin is known to be an area of hydrothermal and mineral groundwater resources. We argue that thermal and chemical anomalies of groundwaters in the strati ed predominantly carbonate succession in the basin are related to the development of transverse high permeability zones, one of the prime results of hypogene speleogenesis. Another result is the high degree of hydraulic connection between individual aquifers in the multi-story aquifer system, a characteristic feature of regional hydrogeology (Lushchik, Lisichenko, Yakovlev, 1988). Hypogene speleogenesis is also likely to play a role in the formation of carbonate-hosted reservoirs, in the migration and accumulation of hydrocarbons in the Prichernomorsky basin. AcknowledgmentsThis study was partially supported by a grant 0110U002248 of the Ministry of Education and Science of Ukraine. ReferencesDublyansky, Yu., Klimchouk, A., Timokhina, E., Spotl, C. 2011. Isotopic indications of water-rock interaction in the hypogene Tavrskaya cave, Crimea, Ukraine. Geophysical Research Abstracts, 13, EGU2011-3055. Klimchouk, A.B., 2007. Hypogene Speleogenesis: Hydrogeological and Morphogenetic Perspective NCKRI Special Paper 1. Carlsbad: National Cave and Karst Research Institute, p. 106. Klimchouk, A.B., Pronin, K.K., Timokhina, E.I., 2010. Speleogenesis in the Pontian limestones of Odessa. Speleology and Karstology, 5, 76 – 93. (in Russian). Klimchouk, A.B., Timokhina, E.I. & Amelichev, G.N., 2009. Hypogene Speleogenesis in the Piedmont Crimea Range. In Klimchouk, A. & Ford, D., eds, Hypogene Speleogenesis and Karst Hydrogeology of Artesian Basins, UISK Special Paper 1, Simferopol, Ukraine. Lushchik, A.V., Lisichenko G.V., Yakovlev, E.A., 1988 Formirovanie rezhima podzemnykh vod v rayonakh razvitiya aktivnykh geodinamicheskikh processov [ The Formation of a Regime of Groundwaters in Regions of Active Geodynamic Processes ]. Naukova dumka, Kiev, p. 160. (in Russian). Pronin, K.K., 2009. Natural Caves of the Prichernomorsko-Azovsky and Moldavsko-Podolsky Karst Regions Ukrainian Institute of Speleology and Karstology, Simferopol, p. 104. (in Russian).



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Issue 11, 2011Speleogenesisand Evolution of Karst Aquifers IntroductionIn karst systems, extended periods of static base level along with active dissolution lead to the development of elevations are believed to be formed by the same event and are collectively termed a level (Palmer, 1987). Knowing the and limited downcutting, revealing information about what was occurring climatically as the levels were forming. Static base level can be related to global glaciations as water is limited and consumed by glaciers. Multiple cave levels form from intermittent local base level lowering caused by changes in regional discharge, river patterns, catchment areas, or climate (Audra et al., 2007; Palmer, 1987). The cave level boundary is change to low gradient phreatic passages (i.e. tubes, caverns). Determining the duration of level development provides insight history of the area. Developing a timeline of events can combine with other area studies to develop an understanding of paleoclimate and demonstrate how upstream events affect regions downstream. Engel and Engel (2009) suggest that by understanding the timing of cave development, researchers can begin interpreting a regions paleoclimate and hydrologic systems. Open cavities underground are pathways for groundwater to uncover paleoclimate and hydrologic history has only been occurring in the past few decades (White, 2007). Through dating the cave sediment, geologists are able to develop a 2004). Sediments accumulate in mature cave passages during static base level and remain in the passages even after deposited sediment provides a record of when water ceased 1Illinois State University, Campus Box 4400, Normal, IL 61790-44002Department of Geosciences, Southeastern Minnesota Water Resource Center, Winona, MN 55987 by the authors. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution licenseEstimating the Timing of Cave Level Development with GISB.S. Jacoby1, E.W. Peterson1*, T. Dogwiler2 and J C. Kostelnick1 Speleogenesis & Evolution of Karst Aquifers )Abstract: Keywords:

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Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Jacoby B.S. et al surface events and can aid in developing a regions climate and geomorphology history. example of where successful sediment dating research has exposed information on the development of a cave system. River using cosmogenic dating of 26Al and 10Be isotopes in cave sediments. Their results showed incision occurred during the Pliocene-Pleistocene in response to various glacial events and the area maintained erosion rates of 2-7 meters per million years (m/my) for the past 3.5 my, despite increased river base level and valley incision that controlled the development of the cave system. The authors concluded that as a result of multiple incision events, a minimum of four levels developed within Mammoth Cave National Park. The authors describe differentiate between the two levels at the highest elevations. experienced about 180 million years of differential lowering between the sandstone units at the top of the plateau and the underlying limestone units. The differential lowering is linked to drops in the elevation of the water table. When the water table elevation maintained one elevation, time allowed for the development of passages and subsequently, levels. As the water table lowered again, rapid incision would terminate level development until the water table reached and maintained a stable elevation and the pattern would repeat itself. Anthony dating of 26Al and 10Be isotopes and found the clastic sediments in the area correlated well with known past deposition, uplift, and incision events in the area. Additionally, the authors River and Cumberland River, which occurred at times similar to those of the Mammoth Cave area. They also found that the area had a similar lithology and climate history to the Mammoth Cave system. Both systems are located within the unglaciated Ohio River Basin and their history of cave development went into the Pleistocene. While numerous work has been published on the denudation in karst systems (Balazs, 1973; Corbel, 1959, 1965; and Oleksynowa, 1971; Plan, 2005; Pulina, 1971; Smith and Newson, 1974; White, 2009), there is limited published research that examines the calculation of the volume lost within a karst system, and none of the published work uses system. There have been other varieties of volume calculation volume (Bocker, 1996; Clarke et al., 2009), gully monitoring (Marzolff and Poesen, 2009), and isostatic rebound of lakes (Yang and Teller, 2005), among others. Collectively, these calculations is an innovative and successful approach.

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Jacoby B.S. et al Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Approximately 290 kilometers east-northeast of Mammoth Carter Caves karst system is located within Carter Caves State Resort Park (CCSRP). The state park is located within Carter (1974), Engel and Engel (2009), Peterson et al. (2011), and Jacoby et al. ( ) all discuss in detail the geology and the hydrogeology of the area. Below is a brief summary of those studies. CCSRP contains about 106 kilometers of Tygarts Creek. Tygarts Creek controls the local base level sandstone, siltstone, and shale. This unit is overlaid by the similar to those found at Mammoth Cave, but have a thinner unit thickness. CCSRP has not been explored to the extent of Mammoth Cave, but is an ideal location to identify cave levels because of the amount of daylighted-caves at various elevations. Cave data can be used to establish the evolution of the cave system. There are over 130 documented caves at CCSRP and over 18 kilometers of mapped passageways. Phreatic caves, active and inactive, in CCSRP tend to follow bedding planes less resistant beds within the limestone (Engel and Engel, 2009). Base level lowering has led to many of the caves in CCSRP displaying an overprinted vadose morphology on the phreatically formed conduits. Caves are found in all limestone Preceding Pleistocene glaciations, the regions landscape developed rather slowly and the base level remained at a stable elevation as compared to changes in the area after the development of large upper-level trunk conduits at Mammoth Peterson et al., 2011). At this time, the headwaters of the Teays River were located on the edge of the Piedmont Plateau periods glaciations even though the area is south of the glacial maximum. As glacial meltwaters incised the area, sediments accumulated in the valleys. Engel and Engel (2009) suggest that remnants of these deposits can be found in the upper levels at CCSRP (i.e. Saltpetre Cave). As changes in base level continued, caves were forming at or below the water two separate cave systems. There is limited published information available that research is growing. An unpublished database concerning the geographic locations of cave openings has been assembled Sediment entrainment dynamics and frequency of the Cave Dogwiler and Wicks (2004). Woodside (2008) surveyed and to evaluate if they were true surface features or collapsed al. (2011) began the work of identifying cave levels within the elevation model (DEM) with a 30-meter by 30 meter horizontal resolution. Those authors proposed a preliminary delineation results in Mammoth Cave and the Cumberland Plateau, which using a 10-meter by 10-meter DEM and introduced the Advancing the work of Jacoby et al. ( ), the eroded during the level development and the interval of time required for each level to develop within CCSRP. Calculating the development time provides a better understanding of the evolution of the park. These calculated times will be analyzed to see how they compare to the speleogenesis of the Mammoth Cave system and the Cumberland Plateau system between the systems would provide insight to the role of base level changes and paleoenvironments on karst development as well as provide more insight into the complicated karst hydrogeology. A secondary hypothesis examined in this work is that the number of cave entrances within each level correlates with the duration of time required to develop that development. This hypothesis relies on the assumption that the number of cave openings was a proxy for passage size. We assumed the number of caves entrances (exits) to be directly related to the duration of cave development because longer exposure to water results in more dissolution greater passage development. Thus, as the river incises through the limestone, be presented below, this hypothesis was shown to be invalid.

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Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Jacoby B.S. et al 1. MethodsJacoby et al. ( CCSRP. The authors referred to the levels within CCSRP as either Option 1, which consisted of 4 levels, or Option 2, which consisted of 5 levels. The difference between the two options is (Table 4). Jacoby et al. ( ) results were used in ESRIs denudation rates from the literature were used to determine the time required to erode the material between each level. and longitudes of cave entrance (exit) locations provided by seamless.usgs.gov. The DEM was used to calculate the area to the National Standard for Spatial Data Accuracy (NSSDA) horizontal accuracy associated with these 10 meter DEMs is approximately 13.906 meters while the vertical accuracy is approximately 0.3632 meters (Blak, 2007). To calculate surface area and volume of removed material with the least amount of distortion, the DEM was converted to elevations from Jacoby et al. ( ) (Table 1) were used in the volume and area of material lost beneath each level. 3D Analysis connects raster cell centers, creating a triangulated irregular network (TIN), and determines its contribution to area and volume. The output volume is the surface area times and 2b). The output volume is only a measurement of the material lost within the valleys. Note that this tool only provides the volume of material lost on the surface and does not measure the volume of material lost within the non-daylighted karst system. Another issue is that an assumption is made that all material that was removed was removed during the development of the next level, which is not true given erosional process will be continuous. The implication of this assumption volume and surface area of each level was calculated through Total Level Volume = (Volume Beneath Top of Level) (Volume Beneath Base of Level) (1) The calculation for the total thickness of material lost needs to consider the variation in topography as seen in the DEM. Therefore, calculating the difference between level elevations is not an accurate estimation of material lost and the quotient of volume over area must be used. To calculate the thickness of lost material, Equation (2) was used. Again, this value is a measurement of thickness lost within the valley, not the thickness of material lost within the existing cave passageways. Total Thickness Lost = (Level Volume) / (Level Area) (2) Option 1 Elevations (m)1Mean Cave Elevation (m) Number of Caves Percentage of Caves (%) 3) Area (m2) Equivalent thickness lost (m) 253-274 262 52 36 399,196,336 14,135,946 28.2 240-253 247 44 30 120,945,389 5,969,867 20.3 228-240 234 37 25 61,563,967 3,052,859 20.2 214-228 222 13 9 39,026,737 2,472,838 15.8 Option 2 Elevations (m)1Mean Cave Elevation (m) Number of Caves Percentage of Caves (%) 3) Area (m2) Equivalent thickness lost (m) 263-274 268 27 19 253,014,693 8,909,453 28.4 253-263 259 25 17 146,181,642 5,226,493 28.0 240-253 247 44 30 120,945,389 5,969,867 20.3 228-240 234 37 25 61,563,967 3,052,859 20.2 214-228 222 13 9 39,026,737 2,472,838 15.8Table 1.1 (Jacoby et al., in review).

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Jacoby B.S. et al Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Once the thickness of material lost (Table 1) was calculated, the amount of time required to remove the material was determined. Time was calculated using equation (3) calculations compares to regional isotopic dating studies (Table 2). Time = (Thickness Lost) / (Denudation Rate) (3) Denudation rates were obtained from the literature gradients and rock type, multiple rates were used in the modeling. White (2009) has established a rate of 30 m/Ma for the Appalachian region, which includes the CCSRP area. greater than and less than to 30 m/Ma to determine the most representative rate. Denudation rates were chosen based on their common occurrence in the literature or their relationship to 30 m/Ma (Table 3). There are multiple denudation rates presented for comparison, thus allowing for an understanding of how sensitive the time calculations are to denudation rates.2. ResultsTable 1 shows the volume and area calculation results for options 1 and 2. Regardless of the option designation, the volume, area, and equivalent material thickness lost for has an estimated volume loss of 39 million cubic meters and an estimated volume loss of 62 million cubic meters and a an estimated volume loss of 121 million cubic meters and a has an estimated volume loss of 400 million cubic meters and 2 has an estimated volume loss of 146 million cubic meters

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Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Jacoby B.S. et al Option 2 has an estimated volume loss of 253 million cubic meters and a thickness loss of approximately 28.4 meters. After using the equivalent thickness lost from Table 1 and the denudation rates from Table 3, the range of level development extent times were found (Table 3). It is possible that speleogenesis took anywhere from 1.69 Ma (at 50 m/ Ma) to 11.85 Ma (at 9.5 m/Ma) to occur (Table 4). Regional karst formation is believed to have begun after 5.6 Ma before The estimation concerning the beginning of karst formation can help narrow down an appropriate denudation rate for CCSRP. to the speleogenesis represented by Option 2 taking 5.63 Ma to form and the speleogenesis represented by Option 1 taking 4.22 Ma to form. The extent of level development in Mammoth Cave and Cumberland Plateau are shown in Table 2. After comparing the timing calculations to isotopic dating studies performed at Mammoth Cave and the Cumberland Plateau, it is evident that speleogenesis. Taking this possibility into consideration, it Table 2 data were estimated and not used for comparisons in this study. Note that levels in for Mammoth Cave and Cumberland Plateau are in reverse order of the designation at CCSRP. Therefore, A and 1 are the oldest and highest elevation at Mammoth Cave and Cumberland Plateau, respectively. Mammoth Cave1CCSRP2Cumberland Plateau3 Age (Ma B.P.)4Extent (Ma) Option 1 Age (Ma B.P.) Cave Option 2 Age (Ma B.P.) Cave Age (Ma B.P.) Extent (Ma) NA 5 5.74 1 5.7-3.5 2.2 A 3.25 0.95 3.38 4 3.37 2 3.5-2 1.5 B 2.3 0.38 3 2-1.5 0.5 C 1.92 0.53 1.97 3 1.97 D 1.39 0.15 1.46 2 1.46 4 1.5-.8 0.7 E 1.24 0.54 0.79 1 0.79 5 0.8 0.812(Peterson et al., 2011)34Ma B.P. stands for millions of years before present. Rate (m/Ma) Climate Conditions (if provided) 9.5 TEMPERATE 12-13 Poland (Pulina, 1971) TEMPERATE TEMPERATE TEMPERATE 20 Krakow Plateau (Corbel, 1965) TEMPERATE TEMPERATE 30 Yucatan, Mexico (Corbel, 1959) TEMPERATE 40 Austrian Alps (Plan, 2005) N/A 50 Mendips, England (Smith and Newson, 1974) Poland (Oleksynowa and Oleksynowa, 1971) TEMPERATE TEMPERATETable 3Table displaying chosen denudation rates and their corresponding geographic location

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Jacoby B.S. et al Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 0.79 Ma to form at 20 m/Ma. This equates to Option 2 taking approximately 5.74 Ma to form and Option 1 taking 3.38 Ma The thickness estimations showed that the greatest volume lost within the system was at the top most levels. The timing estimations indicated that the upper levels also took the longest to form. It is important to note that levels at higher elevations were continuing to erode, even past their suggested the top most elevations because the value of thickness lost includes material lost during the formation of lower levels. Option 2 might have been shorter than 2.37 Ma if the amount of material removed during the formation of lower levels could be eliminated from the thickness lost estimation. Although and Teller, 2005) that modeled landscape development through time, the authors did not address the possibility that surface volume lost at higher elevations occurred during the caused by older levels eroding during the formation of younger levels has not been addressed.3. DiscussionThis study has indicated that one denudation rate is not Table 4 Option 1 Equivalent thickness lost (m) 9.5 m/Ma 12 m/Ma 20 m/Ma 30 m/Ma 40 m/Ma 50m/Ma level 4 28.2 2.97 2.35 1.41 0.94 0.71 0.56 level 3 20.3 2.13 1.69 1.01 0.68 0.51 0.41 level 2 20.2 2.12 1.68 1.01 0.67 0.5 0.4 level 1 15.8 1.66 1.32 0.79 0.53 0.39 0.32 Total system development time possible (Ma) 8.89 7.04 4.22 2.81 2.11 1.69 Estimated system development time (Ma) based on chosen 3.38 Option 2 Equivalent thickness lost (m) 9.5 m/Ma 12 m/Ma 20 m/Ma 30 m/Ma 40 m/Ma 50m/Ma level 5 28.4 2.99 2.37 1.42 0.95 0.71 0.57 level 4 28.0 2.94 2.33 1.4 0.93 0.7 0.56 level 3 20.3 2.13 1.69 1.01 0.68 0.51 0.41 level 2 20.2 2.12 1.68 1.01 0.67 0.5 0.4 level 1 15.8 1.66 1.32 0.79 0.53 0.39 0.32 Total system development time possible (Ma) 11.85 9.38 5.63 3.75 2.81 2.25 Estimated system development time (Ma) based on chosen 5.74

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Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Jacoby B.S. et al this area over time. The actual denudation rate is dependent on the climate, rock characteristics and composition, as well as the amount of precipitation occurring during time of incision (White, 2009). Climate conditions varied during each level that the Appalachian area has maintained a rate of 2-7 m/Ma although the river incision maintained a rate of 30 m/Ma during were averaged together, a rate of approximately 24 m/Ma would have been occurring during the extent of development. This value is not far from the denudation rate established by White (2009). White discussed the denudation rate as a result of various glaciation events whereas this study is attempting to specify denudation occurring between glaciation events. That detail could explain the small differences seen here. The fact that the cave development rates are not similar to area erosion indicates that cave development is more in sync with river incision than other area erosion. This is understandable and Cave Branch both empty into Tygarts Creek which extends through most of the Appalachian karst in northern Kentucky. correlate to the duration of level development, taking the cave development and 2) cave openings are a proxy to cave development. The amount of cave openings did not correlate well with level development time (see Table 1, Table 4, and (19% of registered caves). The shortest level development (30% of registered caves). A reason for the lack of correlation is that cave openings are not a proxy to the extent of cave development and therefore are not solely representative of the volume lost within a level. Instead, the openings are within the rock than a proxy to the size or amount of existing between level development time and cave openings present in each level could be due to the error associated with the total volume of material lost for levels at high elevations includes material lost during the formation of lower levels. This study cannot conclude that, because cave openings do not correlate may still contain larger or a higher frequency of passages, even though they contain a small amount of cave openings. within a passageway rather than simply the number of cave is directly related to development time. The results presented in this study suggest that level formation at CCSRP is similar to the level evolution at the Cumberland Plateau (Table 2). The calculated development times closely match those of the Cumberland Plateau. The correlation could be because both areas have a similar Appalachian terrain while Mammoth Cave is on the western edge of the Appalachian Plateau. The Cumberland Plateau also has a similar contact between the karst and capping silicicalstic units. The lithology change likely contributes to a concentrated area of cave formation at the contact as water levels in CCSRP. Sediments found within the caverns of Cumberland Plateau concede that there was active sediment transport between approximately 5.7 and 3.5 Ma B.P. (Anthony and supports the result of this study that the Carter Caves system was beginning to form between 5.74 and 3.38 Ma B.P. The its formation is possibly the result of a stratigraphic or bedrock change rather than an event causing a change in base level. Transitions from levels 4 through 1 were found by correlating calculated times to regional paleoclimate studies. Multiple dropped between 3.2 and 2.0 Ma B.P. This sea level drop was due to climate cooling and growth of continental glaciers. This 3.0 Ma B.P., followed by another cooling progression at 2.4 Ma B.P. According to evidence in the Cumberland Plateau

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Jacoby B.S. et al Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 longer than about 1.5 million years. After 2.4 Ma B.P., there occurred near 2.0 Ma B.P. during an incision pulse at Parker event, there was a brief pause in river base level. Prior to 1.3 incision and base level stability. The youngest sediments to 0.8 Ma B.P.4. ConclusionsThis study found that volume of material removed, surface within each level increases with level age and level elevation. appears to correlate to greater material removal, especially with these statements since the volume of material lost for the older levels incorporates material that would have eroded during subsequent level development. There appears to be different denudation rates for various levels indicating there is not a universal rate for the system. If one denudation rate had to be chosen from this study, it would be 20 m/Ma. Currently, level development appears to have begun between 3.4 and 5.7 Ma B.P. system. Both the Mammoth Cave and Cumberland Plateau at 274 meters, the contact between limestone and sandstone units. A limitation of this method is that it requires the results results. Choosing the correct denudation rate with this method volume and area was possible for the CCSRP area because because karst development would have to be considered in 3D Analysis tool only calculates volume and area beneath a volume and area. Challenges that are common with volume computing process time, organizing data, software expertise, and varieties within the method chosen. become more accurate. Better accuracy will encourage a increase the versatility of this technology. This research has demonstrated one unique approach, but there are others yet to data improves analysis or how to accurately calculate volume within underground passages. Overall, this method has proven successful in estimating the volume of material removed, surface area, and the is also consistent to other area level studies. Research in similar landscape conditions is needed to support this studys This work contributes to the understanding of the Carter Caves systems evolution and introduces new ways of approaching karst geology.AcknowledgementsThe authors would like to thank the Wittenberg Speleological Society for providing their CCSRP database, CCSRP for providing access to the study area, and two anonymous reviewers who helped improve the message of this article.References multilevel caves along the western escarpment of the Cumberland Plateau, Tennessee and Kentucky, established by cosmogenic 26Al and 10 66 (2), 46-55. 36 (1), 53-68. Balazs, D., 1973. Comparative morphogenetical study of Karst Research Broup of Great Britain 15, 1-8. Blak, T., 2007, DEM quality assessment, in Manual Bethesda, Maryland, American Society for Photogrammetry and Remote Sensing, 425-448. 96, 11-20. Neural Networks Applied to Estimating Subglacial Topography and 22 (8), 2146-2160. 3, p. 1-28.

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Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Jacoby B.S. et al Corbel, J., 1965. Karst de Yougoslavie et notes sur les karst tcheques 5, 245-294. Dogwiler, T., and Wicks, C. M., 2004. Sediment entrainment and 295, 163-172. of Carter Caves State Resort Park and the surrounding area, northeastern Kentucky, in Engel, A. S., and Engel, S. A., (Eds.), Karst Waters Institute, 154-171. ESRI, 2010. ESRI, Inc. 36 (1), 7-13. 273-275. radioactive decay of cosmogenic 26Al and 10Be in Mammoth Cave 113 (7), 825. Caves System Jacoby, B., Peterson, E. W., Kostelnick, J. C., and Dogwiler, T., in 77 (6), 306-314. Jennings, J., 1985. New York, Basil Blackwell Inc. Marzolff, I., and Poesen, J., 2009. The potential of 3D gully 111 (1-2), 48-60. 64 p. Oleksynowa, K., and Oleksynowa, B., 1971. A tentative comparison 5, 93-104. Bulletin 49 (2), 50-66. cave levels and discern the speleogenesis of the Carter Caves karst area, Kentucky, in 29, 2011) 68, 201212. Pulina, M., 1971. Observations on the chemical denudation of some Balcanica 5, 77-92. 39 (1), 113-124. Smith, D. I., and Newson, M. D., 1974, The dynamics of solutional and mechanical erosion in limestone catchments on the Mendip in Institute of British Information Science 65 (4), 255-258. White, W. B., 1988. 69 (1), 76-93. competition between stream erosion, cave development, surface 71 (3), 159-167. in 1991, National Speleological Society, p. 1-10. Woodside, J., 2008. 33 (4), 483-497.



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Issue 11, 2011Speleogenesisand Evolution of Karst Aquifers Corresponding author: Email: tony@geophotos.co.uk ) by the author. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution licenseIntroductionThere is considerable confusion in the wider literature on karst over the terms cone and tower, especially when related (or not related) to fengcong and fenglin. To the extent that the Editor of Cave and Karst Science once said how he this review is meant to provide just that. Much of the earlier literature was weakened because few authors had seen the slowly back in the late 1970s. In its extent, its scale and its variety, the Chinese karst (Fig. 1) is so important that its terms fengcong and fenglin should really take over as the primary international terms, but perhaps their slow acceptance is at least partly rooted in continuing confusion whereby Western and Chinese geomorphologists utilise contrasting parameters This essay is only concerned with the macro-features fenglin from the Chinese terminology. The other widely-known Chinese term, shilin, translates to stone forest, and applies to a giant form of micro-relief; it is essentially a large form of karren or pinnacle karst that forms the surface texture superimposed 1997). Though its largest form relates to arete karst (Jennings, Bik, 1962), which may have the local relief of some fenglin karsts, shilin is not normally a part of the genetic sequence that may link fengcong to fenglin, so is not here considered further here.Cones and towers in the WestWestern karst literature initially emanated from the doline karsts of temperate climatic zones, notably in Kentucky and terrains now within Slovenia and Croatia. Only when the early scientists started to travel abroad did they see a difference in the tropical karst regions, where individual hills were more distinctive than the intervening depressions. Cone karst was the very appropriate term that grew to describe these landscapes of endless conical hills; kegelkarst was its predecessor in the German language. The term was introduced by Otto Lehmann (1926) to describe the Guizhou karst seen on Heinrich HandelMazettis primarily botanical expedition to China. Unfortunately, the classic description of cone karst, of that in Gunung Sewu (Thousand Hills) in Java by Herbert Lehmann (1936), virtually set the type example of cone karst as an area of hills that are 2). The cone karst of Jamaica had already been described, but described as cockpit karst (Danes, 1911; Sweeting, 1958), following local usage that was more concerned with the cockpit depressions than with the intervening hills. Only some decades Guizhou, in China, more fully appreciated by Westerners. Fengcong, fenglin, cone karst and tower karstTony Waltham Cave and Karst Science, 2008, 35 (3). oAbstract Key words

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Waltham Tony Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011FENGCONG, FENGLIN, CONE KARST AND TOWER KARST China was then an almost inaccessible land, but a few travellers got there and a trickle of photographs came out. The incredibly dramatic landscapes of almost vertical-sided limestone hills in Guangxi were glimpsed enough to generate their description as tower karst. The best examples are in the Yangshuo region, though they were (and are) commonly ascribed to Guilin, the larger city that lies not far away in a rather more subdued variety of karst landscape (Fig. 3). Turmkarst is the German term introduced by von Wissmann (1954) to describe the Chinese landscapes, from which the description as tower karst appears to have emanated. Tower karst became the objective and dream of every karst scientist who could not then visit the closed land of China, and the term was applied to various other craggy landscapes of steep-sided limestone hills, most of which do not really warrant the description. Hence was perpetuated; only to be exacerbated when the Chinese terminology, applied to their own hugely important karst terrains, was found to differ in that it is based on different parameters.Fengcong and fenglin in China Chinese geomorphologists distinguish their karst types (in the warm and wet environments) not by the shape of their hills but by the presence or not of a karst plain between the hills. The origins of the terms

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Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Waltham TonyFENGCONG, FENGLIN, CONE KARST AND TOWER KARST lie buried in a karst literature that stretches back for 1200 years (Zhu, 1988), though the fenglin term was probably formalised only by Xu Xiake in 1637. Fengcong (pronounced fungtsung and translating as peak cluster) is a karst with roughly conical hills separated by deep closed depressions, all standing on a common bedrock base so relief. It is sometimes known as fengcong-depression or fengcong-doline topography, and a variant is fengcong-valley karst where there is more interconnection between the dolines. the terminology. It is however clear that entirely vertical sides cannot exist on hills that are clustered together, though some areas of fengcong do have hills with slopes close to vertical on the middle part of their elevations (Fig. 4). Fenglin (pronounced funglin and translating as peak forest) is a karst with isolated hills rising from a plain that is normally formed of limestone bedrock overlain by a veneer of alluvium. It is sometimes known as fenglin-plain topography, and fenglin-polje, fenglin-valley and fenglin-basin are variants determined by the type and extent of the plain between the irrelevant. The best known fenglin is that with vertical sided towers rising from the alluvial plains, but many fenglin hills are also extends to terrains with isolated hills that have very low By dint of his Hungarian nationality, the extensive travels so that he saw more karst than most colleagues of his time. He found the division of tropical karst into tower and cone types height ratios (Balzs, 1973a), though this crossed over variety of fenglin karst in Cuba but would include much of the named after a karst of low relief in the Indonesian Moluccas. These are useful descriptive terms but they do not contribute to understanding of the karst genesis. Fengcong and cone karst fengcong and the Western cone karst are, to a large extent, the same. Even though there are some notable exceptions, this is now a widely accepted generalisation (Zhu, 2005). Typical fengcong terrain consists of roughly equallyspaced conical hills and deep dolines, with local relief that is anything from 30 m to over 300 m. This has often been labelled as egg-box topography, a conveniently descriptive term for the crowded hills with intervening depressions largely devoid of integrated valley systems, but this degree of perfection is rarely attained. The best examples are found in the Guizhou karst in China, where huge swathes of land are formed of very well developed cones that are close to symmetrical and rise to relatively sharp summits (Fig. 5). Detailed measurements across large sectors of the fengcong in western Guizhou revealed remarkably uniform slope angles of 45-47 on cones of all sizes (Xiong, 1992). However mean cone slopes in the fengcong are steeper than 50 in the Shuicheng area (Fig. 5), and many are 55-60 in the Anshun area, both also in Guizhou. by contrasts within the bedrock lithology. Many cones, even by stronger beds within the limestone sequences (Fig. 6), and in steeply dipping limestones. Guizhou cones of weaker, shale-rich limestones have rather lower slope angles (Xiong, 1992). Much of the Caribbean cone karst is also more irregular, due to strong lithological variations in Puerto Rico (Monroe, 1976) and to a host of geological factors in Jamaica (Aub, 1969b). The Gunung Sewu area of Java (Lehmann, 1936; Waltham et al, 1983) is often referred to as the type example of cone rounded summits (Fig. 7), and noticeably lack the much sharper summits of the true cones in the Guizhou fengcong. Their about 30. The same applies to the karst

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Waltham Tony Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011FENGCONG, FENGLIN, CONE KARST AND TOWER KARST hills of the Cockpit Country in Jamaica (Sweeting, 1958), steepen into cliffs around their lower margins. Similarly low domed hills are known in Guizhou where they are formed on dolomitic limestones, and Balzss Tual type of very low domes are formed in young and soft limestones. While the latter two the Javan and Jamaican karsts are formed in strong and hard limestones that may be indistinguishable from those in any of their hill have formed beneath a thicker soil cover that has been retained over their crests. Javas Gunung Sewu lies in an area where soils are regularly replenished by thick volcanic ash, and Jamaicas Cockpit Country has its allogenic soils that are locally valued as bauxite resources. The Chocolate Hills of Bohol, in the Philippines, have slope angles of about 40, intermediate between those of Guizhou and Sewu, and further demonstrate the multiple variations that exist in karst. Sub-types of fengcong include those based on the lateral extent of the clustered cones and their position relative to trunk rivers, karst plains and allogenic catchments (Zhu, 1988) and those based on progressive alluviation where base level is approached by regional surface lowering (Smart et al, 1986). Some of the very crowded fengcong just west of the Li River in the Guilin karst, in its margin this area west of Caoping has hills with nearly vertical sides rising from low pediments that keep them apart; morphologically this provides almost the perfect transition from fengcong cones to fenglin towers, though the genetic The drainage of fengcong karst is almost entirely open sinks at the ends of short ephemeral stream courses within the dolines. Water tables commonly lie far beneath dendritic systems. It is noticeable but not surprising that, where long caves have been mapped through fengcong karst, the passages lie beneath both dolines and cone hills with no correlation to the surface topography (Fig. 8). Phreatic loops do occur within the fengcong caves, and survive until

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Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Waltham TonyFENGCONG, FENGLIN, CONE KARST AND TOWER KARST commonly abandoned and perhaps subsequently intersected at multiple high levels. The laterally extensive, vadose, cave drainage further distinguishes fengcong from fenglin. The extensive and spectacular fengcong karst of Guizhou (and northwestern Guangxi) is already recognised as the term is retained for descriptive purposes. Fengcong karst is widely distributed through the wet tropical regions of the world, but none quite matches the extent and scale of that in Guizhou.Fenglin and tower karstAgain there is widespread similarity between the Chinese fenglin and the Western tower karst. Almost all true tower karst can be described as fenglin, though the latter term does include some landscapes that comprise conical hills instead of towers. Even with these exceptions, some writers are now accepting that fenglin and tower karst are essentially the same (Zhu, 2005). isolated, steep-sided towers rising from an alluviated plain, which is commonly covered in rice paddies (Fig. 9). The fenglin of Yangshuo, at the southern end of the Guilin karst, represents the geomorphological extreme that has so often been the subject of traditional Chinese paintings and drawings. Numerous individual towers are well over 100 m tall. Balzs of less than 0.5, so that they are two or three times as tall as they are wide, and thereby form one of the worlds most spectacular landscapes (Zhu, 1988). Many towers do have vertical sides (Fig. 10) and are the more dramatic when they lack any aprons of talus around their bases; some of those around Yangshuo, nearby Fuli and Others in the same areas are more truly conical, notably in in a small sample area of the fenglin near Yangshuo revealed a mean slope angle of 75 (Tang, Day, 2000). The same in the fenglin and fengcong (in sample areas between Guilin and Yangshuo); this may have been due to the locations and small sizes of the sample areas, as it is not supported by visual observation that is admittedly non-quantitative (comparing Figs. 6 and 9 as an example). Most fenglin towers do have sides steeper than are found on most fengcong cones. There is however a transition through many fenglin towers that have by having the alluviated karst plain between them. There is also a transition through towers that have multiple peaks and through very small clusters of hills in the middle of a karst plain; the latter have been described as insular fengcong (Zhu, even conical towers in steeply dipping limestones (Fig. 12) and can only survive in strong and almost horizontally bedded limestone (Fig. 13). Fenglin karst can exist with low conical hills, commonly

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Waltham Tony Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011FENGCONG, FENGLIN, CONE KARST AND TOWER KARST

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Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Waltham TonyFENGCONG, FENGLIN, CONE KARST AND TOWER KARST in thinly bedded dolomite carbonates. The Chocolate Hills of Bohol, in the Philippines, are also low cones, and are in pure limestone, though this is young and friable (Balzs 1973b); it as fenglin, have developed by more alluviation than exists in fengcong terrains with similar hills, such as Gunung Sewu. basin, polje or valley in order to further describe the extent of the plain areas between the towers (Zhu, 1988). Karst margin fenglin describes terrains with isolated towers that lie between allogenic sediment in the development of fenglin (see below). Drainage in fenglin is primarily on the alluviated plains between the towers, where substantial dendritic systems of surface rivers can survive. Within the limestone, a relatively stable water table is maintained at the level of these rivers. (Worthington, 2004), though there are few large risings in the fenglin that could indicate any degree of maturity in such also penetrated by some caves that happen to carry the plains rivers through them (Fig. 14). Vadose drains within the towers are close to vertical, and commonly intersect old, high-level passages that originated as foot caves at past plain levels. The famously spectacular fenglin karst of the GuilinYangshuo region in eastern Guangxi is already recognised as almost entirely restricted to the limestone regions of Southeast Asia, extending from Guangxi into northeastern Vietnam and then only into isolated patches through the rest of Vietnam, Thailand, Burma and Indonesia. Caribbean mogote karst, notably in Belize, Cuba and Puerto Rico, may be regarded as a variety of fenglin with generally reduced local relief.Fengcong evolution It is widely accepted that fengcong karst is a natural evolutionary progression from doline karst, created when the dolines enlarge towards coalescence, leaving residual hills that What is open to debate is the extent of any early stage of valley systems within the fengcong. Some parts of Javas Gunung Sewu karst have the remains of dendritic valley systems that only just broken into chains of dolines between the conical hills. It is likely that these valley systems were superimposed from a non-karstic cover now totally removed from the limestone; such valleys would have survived on the limestone until such new sinks along the valleys would progressively deepen into strings of dolines. Valley incision into the limestone when it was sealed in periglacial environments, as was the case in many tropical fengcong terrains. Other parts of the Gunung Sewu karst lack any recognisable linear patterns within their dolines, as appears to be the case in much of Guizhous fengcong, but continued maturation of the fengcong is eventually likely to remove all trace of inherited valley patterns. Alignment of dolines, and their low intervening saddles, creates corridors through some areas of fengcong karst (Fig. 15). At many sites these can clearly be attributed to geological controls, either by major fractures or

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Waltham Tony Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011FENGCONG, FENGLIN, CONE KARST AND TOWER KARST by individual beds within steeply dipping limestone sequences. Such corridors have been interpreted in Jamaicas cockpit karst (Sweeting, 1958; Aub, 1969b), but this may be a circular argument in such heavily forested terrains where the geology is largely interpreted from air photographs. Collapse features that may add to the morphological complexity of the fengcong include the giant dolines known as tiankengs (Zhu, Waltham, 2005). There are even suggestions relief fengcong in China could have originated by collapse (Klimchouk, 2005), though collapse is generally dismissed as of little importance in the development of the cone karsts of lower relief outside China (Sweeting, 1972). Within the well watered, forested, cockpit karst of Jamaica, it has been noted that, once established, deep dolines are self-perpetuating by diversion of rainwater, and hence dissolutional effort, towards their low centres (Aub, 1969a; Smith et al, 1972). It is clear that fengcong karst normally evolves towards higher local relief as long as the surface lowering of doline regional base level. Mature fengcong with the greatest local relief therefore requires rapid or intermittent tectonic uplift to keep it rejuvenated with deepening of its dolines. With slower from surface lowering towards lateral planation, so that the fengcong may then evolve into fenglin karst. Within China, the fengcong of Guizhou has been described as a feature of the plateau-canyon karst of the Guizhou type, the latter being a broader term to distinguish it from the peakrecognizing the base-level lowering and rejuvenation that is so important in the evolution of mature fengcong karst. Fenglin evolution A key process in fenglin karst is the enhanced rock dissolution that takes place due to the chemically aggressive water occurring at the water table. This level has very little vertical variation either side of the level of the alluvial plain, in the style of the level control (known by the German term ) that has long been recognised as critical to the lateral undercut any rising slopes marginal to the alluviated plain, by the creation of dissolutional notches (Fig. 16) and foot caves.

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Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Waltham TonyFENGCONG, FENGLIN, CONE KARST AND TOWER KARST With subsequent collapse over these undercuts, cliff retreat is accelerated at lower elevations, and the whole process effectively turns a cone into a tower (Fig. 17). creates the commensurate extension of the base level plain, and so constitutes a transition from fengcong to fenglin. This does however require a stable base level and water table, and the processes in nature are greatly complicated by the common normal situation of a slowly falling base level. Critical are the relative rates of base level decline, dissolutional lowering of the rock surface beneath the alluvial plain, surface denudation on the karst hills, and sediment input that maintains the evolving alluvial plain. The underlying factor of base level decline is a function of both regional denudation and tectonic uplift. Zhang Zhigan presented the thoughts of himself and others, most notably Lu Yaoru, in an important paper (1980) that established the key role played by the local rates of tectonic uplift in distinguishing the fenglin and fengcong types of karst landscape. Debate continues over the early evolution of fenglin, but it is recognised that, whatever its origins, fenglin karst only exists where a number of independent factors combine to create the right environment (Fig. 18). The rarity of the perfect combination accounts for the scarcity of mature fenglin worldwide. These factors may be listed (in no particular order) 1. Limestone that is pure, compact and strong. massive surface lowering, without reaching the base of the limestone, which gives time and space for the karst landscapes to evolve to maturity. 3. A veneer of alluvium overlying the bedrock limestone of a karst plain. 4. A karst water table that is stable and is maintained at the level of the karst plain. that can recharge and maintain the alluvial plain as it evolves through surface and bedrock denudation. 6. Slow tectonic uplift that matches surface denudation and thereby maintains the karst plain as it is lowered through dissolution in a regime of abundant biogenic carbon dioxide. 8. Equilibrium between rates of surface lowering and lateral planation that allows maintenance of the residual towers while the karst plain is lowered around them. In simple terms, fenglin is a very mature form of karst terrain that can only evolve during surface lowering through a great thickness of limestone; furthermore it requires long-term lowering of an alluviated karst plain, which is only possible where slow tectonic uplift is matched by both its own bedrock denudation and sediment supplies that maintain its alluvial cover. There has been considerable debate over whether fengcong and fenglin evolve separately or whether fenglin evolves from fengcong. Most early ideas focussed on separate origins, dependent on bedrock porosity, bedrock fractures, recent studies recognise fenglin that is both evolved from fengcong and separate from it, though with the evolved style dominant in the Guilin area (Williams, 1987; Ford, Williams, 2007); the separate style includes various types of nontropical, geologically controlled tower karst. The more isolated karst hills in Jamaica are ascribed to development where there is more insoluble sediment (analogous to the input of gravel where fenglin evolves), and this is claimed to be independent of development of the more widespread fengcong cone karst (Day, 2004); however the evidence is not conclusive, It is possible to identify a complete genetic sequence that originates from a plain surface, evolves into a doline karst and then into fengcong, and then matures into fenglin, before degrading in old age back to a karst plain (Fig. 19).

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Waltham Tony Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011FENGCONG, FENGLIN, CONE KARST AND TOWER KARST which is enormously more complicated in nature where both regional and local factors impose. But it incorporates all the stages do provide a genesis for the tall limestone towers of the classic fenglin karst around Yangshuo. Multiple levels of sets both indicate that some areas of fengcong have complex multi-phase histories that reach far beyond the simple sequence in Figure 19. Within the extensive and varied karst of Guangxi, both fenglin and fengcong appear in such juxtaposition that suggests parallel evolution of the two systems (Zhu, 2005). On a regional scale, this can be accounted four stages in an area of rapid tectonic uplift, while a lower rate of tectonic rise allows fenglin to develop by passing from stage 2 direct to stage 5. But tectonic contrast cannot account for different landforms within units only a few kilometres across; in these cases, the critical factor on such a local scale can only be sediment input Zhang (1980) recognised that the evolution of fengcong through rejuvenation of upland terrains could be extended into a landscape sequence that included fenglin; but he suggested that this was an overcritically dependent on contrasts in tectonic uplift between Guizhou and Guangxi and plateau surface. Mature fengcong could diverge from the total sequence at stage 4 and continue to increase its local relief under conditions of rapid uplift and repeated rejuvenation.Timescales of karst evolutionIt is clear that the mature forms of fengcong and fenglin, particularly as seen in the karst terrains of Guizhou and Guangxi, have both evolved over very long periods of time, and there is implication that the fenglin probably has the longer timescale of the two. Some evidence for the lengths of these timescales comes from dated materials in the caves of the fenglin karst around Guilin. Most of these caves are richly decorated with massive deposits of calcite, and stalagmites in the caves of Maomaotou Hill, in the suburbs of in both warm and cold stages through the Pleistocene (Wang, 1986). The karst is clearly much older. An important record has come from palaeomagnetic studies of clays in a tiered series of caves within a single tower,

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11Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Waltham TonyFENGCONG, FENGLIN, CONE KARST AND TOWER KARST known as Chuan Shan or Tunnel Hill (Fig. 20), which rises on the east bank of the Li River in the southern suburbs of Guilin (Williams, 1987). These cave deposits indicated a mean rate of plain lowering, and therefore of tower emergence, of not more its interpretation shows only the emergence from which the tower might have evolved. Data from a range of other sources indicate rather higher rates of surface lowering in the Guilin basin. Zhang (1980) cites 80-120 data on fossils in the high-level caves, and studies. Lu (1986) estimates denudation ka in the Pleistocene, increasing in the Holocene. ka would therefore seem reasonable for the long-term rate of surface lowering in the Guilin karst. The geology indicates that denudation has worked down somewhere in the order of 1000 m of limestone, and this therefore extends the timescale of the karst evolution to around 10-20 Ma. These very karst well back into the Tertiary, and this appears to be a very reasonable concept for both the fengcong and the fenglin until more precise chronological data is available.Fenglin fengcong distribution appreciate the enormous variety of detail in the karst landscapes of Guangxi and Guizhou. It is very clear that multiple factors have been at the same time at each site. Consequently there is no simple pattern in the distribution of fenglin and fengcong. On the largest scale, fengcong dominates the uplifted karst of the Guizhou plateau, while fenglin is largely restricted to the more stable lowlands of Guangxi. Both fengcong and fenglin occur within the relatively small karst in the Guilin-Yangshuo basin (Fig. 21). Many of the fenglin areas are associated with sediment

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Waltham Tony Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011FENGCONG, FENGLIN, CONE KARST AND TOWER KARST fans of rivers derived from the adjacent non-carbonate hills, while the lower gradient of the trunk Li River precludes its ability to transport sediment so that it has entrenched a gorge scale, a valley within the heart of the fengcong karst of Anshun, in Guizhou, contains two perfectly formed towers on an alluvial where there was sediment input, as tectonics could have had Another variation is provided by the Khammouan karst in Laos (Waltham, Middleton, 2000), where large blocks of fengcong have very steep perimeter walls that drop to river fenglin where alluvial plains meet the high hills. The larger hills in Cubas Sierra de los Organos karst are comparable blocks of fengcong, but the steep marginal cliffs drop to adjacent plains where smaller mogotes form a variety of fenglin (Fig. 24). smallest clusters of towers that stand on alluvial plains in Guangxi, and also the small, isolated, limestone hills that rise from the poljes and marginal plains within the fengcong of one or more of the factors, as listed above, that are critical geology and pre-existing trunk valleys that are superimposed on the karst processes and are not yet mapped and fully appears to be a truism that fenglin is polygenetic.Fenglin variants With fenglin evolving under a number of different variation in the morphology of its towers. The splendid tall towers of the Yangshuo area are merely the extreme form of

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Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011 Waltham TonyFENGCONG, FENGLIN, CONE KARST AND TOWER KARST fenglin development. Variations in detail are recognised from contrasting evolutions in the Guizhou karst (Smart et al, 1986), where some areas evolve to fenglin while retaining conical hills rise from alluvial plains in the Philippines Bohol karst (Balzs, 1973b) and in some parts of Puerto Rico (Monroe, 1976; Day, 1978); both of these are known as cone karst but are truly varieties of fenglin. The steep-sided mogotes of Cubas Sierra de los Organos (Pano, telcl, 1968) are low versions of fenglin towers, perhaps representing stage 6 on Figure 19. Both fengcong and fenglin are essentially features of karst within the hot and humid tropical environments where mean temperatures are above 17C and annual rainfall exceeds 1300 mm. Parts of the Nahanni terrain, in the colder climes of Canada, have been described as tower karst (Brook, Ford, 1978). However, these may be viewed as geologically controlled plateau remnants that have evolved from the labyrinth karst (in similar style to buttes developing from mesas in Arizonas Monument Valley). They may be described as towers, but they are not fenglin. A special variant of fenglin is created where karst plains have been invaded by the sea so that the residual towers are further undercut by wave action and marine dissolution. The 2000 islands of Ha Long Bay, Vietnam, include spectacular examples of both drowned fenglin and drowned fengcong (Waltham, 2000). of karst that has clear genetic implications, and are also the terms established in the worlds most extensive and most important karst terrain, in southern China; for both these reasons they should take precedence in good science. Cones and towers are useful descriptive terms for karst landforms, but they have been distorted by different localised usages (Fig. 25). They may be recognised as approximate correlations with fengcong and fenglin, but are better retained as purely As a term, tower karst has been over-used in Western literature, largely as a purely descriptive label for a fairly steep, rocky hill. Isolated crags formed in thin and steeply dipping bands of limestone that protrude high above adjacent weaker rocks, in parts of Cambodia, Thailand and elsewhere, have been described informally as towers on numerous occasions. Frost

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Waltham Tony Speleogenesis and Evolution of Karst Aquifers, Issue.11, 2011FENGCONG, FENGLIN, CONE KARST AND TOWER KARST shattered crags in Tibet, and even steep crags in reef limestone in the English Peak District, have been similarly labelled. All of these, and many more, may better be regarded as pseudotowers, as they lack the surrounding karst plains; they certainly cannot be described as fenglin. Some areas of mogote hills in Cuba and Puerto Rico constitute a true variant of fenglin, but too many rocky hills within the Caribbean karsts have been misleadingly described as towers, and none compares with Large swathes of Guangxi have been sweepingly described as tower karst (Sweeting, 1972), whereas fenglin forms only 15% of the karst area within the province (and even only 50% within the Yangshuo area), the remainder being fengcong. Furthermore, the entire subtropical karst of southern China is sometimes described as the fenglin karst system (Xiong, 1992; Zhu, 2005). Confusion appears to be alive and well within the terminology of karst. It appears that it would be an improvement to use the terms fengcong and fenglin more widely, and relegate cones and towers to descriptive use having only approximate correlation with the Chinese landforms.AcknowledgementsThe concepts developed above have developed over years of travel and exploration within many of the worlds great karst produced by others who have mused on the complex evolution of karst. In particular the author is grateful for many discussions Geology in Guilin, whose comprehension of the karst terrains in his home country is perhaps second to none. However, no debate on karst geomorphology can ever be considered as terminated, and the author takes full responsibility for words that may have strayed from reality within this essay.References Aub, C, 1969a. The nature of cockpits and other depressions in the karst of Jamaica. Proc. 5th International Congress of Speleology Aub, C, 1969b. Some observations on the karst morphology of Jamaica. Proc. 5th International Congress of Speleology (Germany), Balzs, D., 1973a. Relief types of tropical karst areas. Proc. symposium on karst-morphogenesis, International Geographical Union, European region conference (Hungary), 16-32. Balzs, D., 1973b. Karst types in the Philippines. Proc. 6th International Congress of Speleology (Czechoslovakia), 2, 19-38. Brook, G.A., Ford, D.C., 1978. The origin of labyrinth and tower karst and the climatic conditions necessary for their development. Nature, 275, 493-496. Danes, J. 1911. Le karst du type Goenoeng Sewu ou cockpit country. Bulletin de la Socit Serbe de Geographie, 11, 310-313. Day, M.J., 1978. Morphology and distribution of residual limestone hills (mogotes) in the karst of northern Puerto Rico. Geological Society of America Bulletin, 89, 426-432. Day, M., 2004. Cone karst. In Encyclopedia of Caves and Karst Science, Gunn, J. (ed.), Fitzroy Dearborn: New York, 241-243. Ford, D., Williams, P., 2007. Karst Hydrogeology and Geomorhology. Wiley: New York, 562pp. Jennings, J.N., 1985. Karst Geomorphology. Blackwell: Oxford, 294pp. Jennings, J.N., Bik, M.J., 1962. Karst morphology in Australian New Guinea. Nature, 194, 1036-1038. process. Cave, Karst Science, 32, 93-98. Lehmann, H., 1936. Morphologische Studien auf Java. Geographische Abhandlungen, Serie 3, 9, 1-114. Lehmann, O., 1926. Die geographischen Ergebnisseder Reise durch Kweitschou, Expedition Dr Handel-Mazetti 1914-1918. Denkschrift Akademie Wiss Wien Mathematic Natur, 100, 77-99. Lu Yaoru, 1986. Karst in China. Geological Publishing House: Beijing, 288pp Monroe, W.H., 1976. The karst landforms of Puerto Rico. U. S. Geological Survey Professional Paper, 899, 69pp. Pano V., telcl, O., 1868. Physiographic and geologic control in develoment of Cuban mogotes. Zeitschrift fr Geomorphologie, 12, 117-173. Smart, P., Waltham, T., Yang Mingde, Zhang Yingjun, 1986. Karst geomorphology of Western Guizhou, China. Transactions of the British Cave Research Association, 13, 89-103. Smith, D.I., Drew, D.P., Atkinson, T.C., 1972. Hypotheses of karst landform development in Jamaica. Transactions of the Cave Research Group G. B., 14, 159-173. Song Linhua, Waltham, T., Cao Nanyan, Wang Fuchang (Eds.), 1997. Stone Forest, a Treasure of Natural Heritage. China Environmental Science Press: Beijing, 136pp. Sweeting, M.M., 1958. The karstlands of Jamaica. Geographical Journal, 124, 184-199. Sweeting, M.M., 1972. Karst landforms. Macmillan: London, 362pp. Tang, T., Day, M.J., 2000. Field survey and analysis of hillslopes on tower karst in Guilin, southern China. Earth Surface Processes and Landforms, 25, 1221-1235. Waltham, T., 2000. Karst and caves of Ha Long Bay. International Caver, 2000, 24-31. Waltham, T., Middleton, J., 2000. The Khammouan karst of Laos. Cave, Karst Science, 27, 113-120. Waltham, A.C., Smart, P.L., Friederich, H., Eavis, A.J., Atkinson, T.C., 1983. The caves of Gunung Sewu, Java. Transactions of the British Karst Research Association, 10, 55-96. Wang Xunyi, 1986. U-series age and oxygen carbon isotopic features of speleothems in Guilin. Proc. 9th InternationalCongress of Speleology ( Spain), 1, 284-286. Williams, P.W., 1987. Geomorphic inheritance and the development of tower karst. Earth Surface Processes and Landforms, 12, 453-465. Wissmann, H. von, 1954. Der Karst der humiden heissen und sommerheissen Gebeite Ost-Asiens. Erdkunde, 8, 122-130. Worthington, S.R.H., 2004. Hydraulic and geological factors Xiong Kangning, 1992. Morhometry and evolution of fenglin karst in the Shuicheng area, western Guizhou, China. Zeitschrift fr Geomorphologie, 36, 227-248. Yuan Daoxian, 2004. Yangshuo karst, China. In Encyclopedia of Caves and Karst Science, Gunn, J. (ed.), Fitzroy Dearborn: New York, 781-783. Zhang Zhigan, 1980. Karst types in China. GeoJournal, 4, 541-570. Publishers, 188pp. Zhu Xuewen, 2005. Karst areas and karst types in China. Geographische Rundschau (International), 1(2), 37-47. description. Cave, Karst Science, 32, 75-79.



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Issue 11, 2011Speleogenesisand Evolution of Karst Aquifers 1.IntroductionThe article deals with a number of paleokarst features found and investigated by the author from 2001 to 2004 around the village of Saint Remze. The main discovery which could be followed over the unusual length of more than 5 km. It is important for the understanding of the regional informative for dating the speleogenesis. Corresponding author: Rue du Perbet, 07700 Saint-Remze, Ardche, France under the terms and conditions of the Creative Commons Attribution license Paleokarst investigation near Saint-Remze, Ardche, France: discovery of an underground river fossilised during the Messinian salinity crisisJ.E.J. Martini Speleogenesis & Evolution of Karst Aquifers content )Abstract: Key words:

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Martini J.E.J. 2.Geological framework and basic geomorphologyThe sector under investigation is part of the prestigious caving domain of the Basse Ardche (Figures 1 and 2). Near to Barremian marls. This limestone is overlain by Aptian to Miocene marls and sandstones. The Mesozoic strata have been very moderately folded during the Upper Eocene by a out to the NW in the Cvennes Mountain Range (Rouire and are disconformably covered by the Coirons Plateau basalts of trachytes and phonolites. These volcanics rest directly on the The geomorphology has been studied by several authors and generally accepted as Upper Miocene. South of Saint limited to the SW by the Ardche Canyon and to the SE by an the presence of ancient streams. The karst developed on the Urgonian limestone is

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Martini J.E.J. Most of the karst springs are located at the level of the imperceptibly into a structural slope marking the stratigraphic top of the Urgonian limestone and getting progressively roughly limits the karst domain in the East. This alluvial plain because of less erosional power. These shallower canyons are all developed in karst rock. This characteristic could have 3. Description of paleokarst caves boulders are scattered on the ground or removed and piled up on walls in order to make the land amenable to cultivation. It is often not possible to locate their origin with precision (Fig. and therefore has been investigated in detail. It consists of a number of segments mainly developed on the slope marking the transition from the Saint Remze Plateau to the Malbosc Surface (Fig. 4). The former passage appears as bands and may vary from 5 to 20 m. Although genuine outcrops of karst favourable conditions the walls display observed. elevations and to its ceiling in the highest ones. Therefore on the topographic map (Fig. 4) it is possible to estimate the passage shape is taken into account. Its elevation does not vary much. According to the points karst segments can easily be connected to

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Martini J.E.J. the segments is becoming confusing and the connections are a generally lower altitude than previously. Some of them give the impression to terminate abruptly at both ends. Although the (Fig. 10). from the base to the middle part of the Urgonian limestone. neotectonics. speleothems.4.1. Immature alluvials long fossil channel from Aiguizier I to Marzal V and in the parallel been intersected by the vertical shaft of the Aven du Devs de Usually the hardened form is observed in outcrops or in and lenticular layers. A characteristic nature of the sandstone is a glittering facies due to cleavages in large calcite crystals

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Martini J.E.J. to petrographic analysis (Fig. 12). It underlines the immature metamorphic rocks (micaschist) and of volcanic rocks. The less pronounced and grades from complete to practically nil. II is compared with one of Upper Pleistocene alluvium of the grains is identical. They were dominantly transported from

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Martini J.E.J. Upper Miocene volcanics (Fig. 1). Their immature nature indicates that they have been eroded from unweathered outcrops in rugged terrains. which suggests transport in torrential streams and crushing by large pebbles. As in the endogenic fragments are also present pie diagrams of Fig. 12. In the coarse does not seem to rise above 20 %. They include limestone and calcite rods from speleothems which are recognisable by a reddish banding perpendicular to the possibly also of endogenic origin. In this category one may perhaps include a few sometimes resembling water drops. An unusual facies has been observed at the end of the Bartade Cave. It consists of an

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Martini J.E.J. paragenetic channel developed at the ceiling and seems to mark the end of the immature sedimentation. These laminites 4.2. Mature alluvials and colluvialsThey have been observed over the entire length of the fossil channel as well as in most of the other paleokarst pockets in the Saint Remze surroundings (Fig. 4). This deposit consists structure. In some rare instances the red clay had been of organic matter originally present in the sediment. Detritic elements in sand and sandstone reveal only and goethite. These minerals are comparable to the endogenic material described in the previous section. They probably originate from the same metamorphic basement as suggests that basalt might have been present at the onset. The have formed in the cave itself or perhaps have originated from might have been present on the Saint Remze Plateau. The which the three most common elements are well represented.

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Martini J.E.J. This phenomenon is certainly due to mechanical separation by density (placer effect). limestone. The fragments can often be supported by a beige or They have been observed practically over the entire length of the fossil channel. The origin is very certainly from wall and ceiling gelifraction. 4.4. Speleothems Speleothem calcite is generally largely crystallised and red to which is often characteristic of deposition under variable cave entrances. This latter type has been observed in Devs II and in the highest parts of Marzal I. Millimetric to centimetric thick crusts of goethite have 5. Palaeontology and biostratigraphy sites (Fig. 4). Eight of them proved to be rich enough to provide 5.1. Rounal I depositThe fossiliferous horizon consists of lenses of coarse sandstone and sand belonging to the immature type. The lenses Occitanomys adroveri Stephanomys dubari Paraethomys cf meini Apodemus cf gudrunae Apodemus cf gorafensis Apodemus cf jeanteti Apocricetus barrierei Neocricetodon cf polonicusThis fauna is characteristic of the upper part of the biozone palaeontological data with the karst and general morphological 5.2. Costes Chaudes II depositThis fossiliferous deposit consists of red sandstone boulders derived from mature coarse alluvials. The material Stephanomys donnezani Apodemus jeanteti Apodemus gorafensis Apodemus dominans Rhagapodemus frequens Occitanomys cf brailloni Occitanomys cf ellenbergeri Apocricetus sp Dolomys occitanus Trilophomys sp Glis cf sackdillingensis Eliomys intermediusThe Costes Chaudes II fauna is characteristic of the upper speleogenic calcite revealed an Apodemus of the type and a rootless located in the NW end of the Marzal I segment (Fig. 4)and in a Apodemus and plus These two animals indicate a Pleistocene age for the breccia facies. This age is also supported by the gelifracted nature of the breccia.

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Martini J.E.J. 5.4. Arredons W depositThis deposit is situated outside the long unroofed cave were collected on a stone wall. The primary deposit has not the fragments were observed well grouped on the wall. The Occitanomys adroveri Paraethomys meini Apodemus cf jeanteti Apocricetus barrierei Neocricetodon polonicusThis fauna shows similarities with the species found in Rounal I and in particular with the great dominance of in both deposits. The most obvious difference is the absence of in the Arredons W deposit. If this the age would be Lower Pliocene (MN14 zone). 5.5. Arredons E depositA few fragments of fossiliferous sandstone and breccia have been collected on stone dumps left after land clearing and This association suggests the MN15 zone in the Pliocene. Apodemus jeanteti Apodemus dominans Stephanomys cf donnezani Paraethomys sp Neocricetodon cf intermedius Mimomys sp suggest the upper MN15 biostratigraphic zone.6. Distribution, stratigraphy and sedimentology that the four facies should be present over nearly the entire that these fragments are more abundant in the high parts of of the outcropping detritic sediments have also been noted in the highest elevations. The immature sediments seem to If there is no evidence that the lower parts of the channel the highest parts and would be related to a large abundance of overlaying speleothems. The mature sediments also seem to be located in the top Bartade Cave immature and mature sediments form alternating have been introduced into the endokarst continuously up to palaeontological deposit of Arredons W (MN biozone 14 or Pleistocene gelifraction breccia have also been generally under the top. The breccia probably developed when the occurred. Although the two observed palaeontological ages a result of denudation progress.

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Martini J.E.J. Speleothem calcite is associated with all the detrital where it is associated with the immature facies. In the Devs been noted in boulders in Devs II and IV. In Devs III a loose immature sediments deposition is concomitant and therefore underground river for this fossil channel. It is nevertheless Relatively recent erosion and weathering of the paleokarst under cover was certainly enhanced by concentration channel (= doline effect). Recent dissolution and reworking is evidenced by detrital accumulations into younger cavities (Fig. a pothole in which immature sandstone has been incorporated with an archaeological breccia of Middle Pleistocene to phases intersected and partly eroded the immature sediments. deepened the old riverbeds over some lengths which probably may perhaps speak of palimpsests of the original channel. This point out that the model is provisional and in the future should 7. Speleogenesis and impact on the regional karst and morphological evolution at least two ponors on the bank of the Ardche River (Fig. that it developed in the immediate vicinity of the water table. These observations allow estimating the position of the ponors phreatic channel. Sustained speleogenesis could have shaped should have been responsible for the development of this system. Indeed a total would have rapidly collapsed into a canyon /sec. At the not far away from its present course. deviated to the East and should have been this surface. Considering that the relative elevation of the underground river remained

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Martini J.E.J. this value represents the proper lowering of the surface. 11 m/ erosion would have lowered it much more. This suggests that 5 could have been active only before the rapid lowering of the punctured by mining activity at more than 1000 m below the shown that speleogenesis can rapidly develop in such cases One may visualise the position of the resurgence of this underground river by virtual restoration of the strata eroded NW of the sedimentary cover suggests that the water was returned to the Ardche via a resurgence positioned where the limestone disappeared under the impervious terrain slope of the underground river should have been about the same than the Messinian Ardche. Furthermore one may into account the rectilinear distance of 24.5 km between the position at the brink of the deep salinity crisis (Fig. 15). This The underground river could have been still active not have reached the karst domain yet. This delay time could have allowed the underground river to be still active. This is the regressive erosion due to the drying out of the Mediterranean Sea. Alternatively another model could the result of an accretion period for the riverbeds. This could have been related to lago mare. This period would have taken place immediately before the formation of of the upper and the lower evaporites (from accretion phase is suggested by the alluvial reached an original thickness of at least 50

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Martini J.E.J. 8. Conclusion appears. Indeed this surface should have been situated 50 to consideration. The hypothesis of a more or less continuous already suggested by the relief and immature alluvial covered Canyon was not well materialised yet. The river was probably 2002). It appears that this symmetry is more morphological than chronological. speleogenesis took place during the Pliocene and the It appears also that the voluminous caverns in the region could have rapidly formed by absorption of important surface streams into the endokarst. This process could represent an alternative to the hypothesis of a speleogenesis under ancient around Saint Remze suggests that elsewhere similar deposits might also be widespread. This palaeontological approach a routine method.References encaissement des valles au cours du Nogne et du Quaternaire Gologie de la Docum. Lab. la France. Quaternaire Parathethys) during the late Neogene: the Mediterranean Lago Mare deciphered. Gologie de la Quaternaire sondage de Pierrelatte (Drme). 4015. analysis of numerical models. West Rand Gold Field of South Africa. crise de salinit messinienne. Quaternaire 2004. Chronostratigraphy of the key Upper Miocene (Lower Turolian) 40Ar/ basalt. Bull.

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Martini J.E.J. morphogense lente.



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Issue 11, 2011Speleogenesisand Evolution of Karst Aquifers IntroductionThe island of Fais is located 220 km east of the island of 1 Mississippi State University, Department of Geosciences, Mississippi State, MS 39762, USA2 University of Guam, Water and Environmental Research Institute of license 1122 Freile, D., and Park, L. eds., 2008, Proceedings of the 13th Symposium on the geology of the Bahamas and Other carbonate regions, p. 135-139. Speleogenesis & Evolution of Karst Aquifers( )Abstract: Fais Island, which lies about 200 km east of Yap, Federated States of Micronesia, in the Caroline Islands of the Western Keywords:

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observations: simple carbonate island in island carbonates, Groundwater



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Issue 11, 2011Speleogenesisand Evolution of Karst Aquifers IntroductionThe purpose of the research reported here was to take the Eolianites and Karst Development in the Mayan Riviera, MexicoKristin N. Kelley1, John E. Mylroie1*, Joan R. Mylroie1, Christopher M. Moore1, Laura R. Collins1, Lica Ersek1, Ioan Lascu1, Monica J. Roth1, Paul J. Moore2, Rex Passion3, Charles Shaw4 Davis, R. L., and Gamble, D. W., eds., 2006, Proceedings of the 12th Symposium on the Geology of the Bahamas and Other Carbonate Regions, p. 88-99.1 Department of Geosciences Mississippi State University, Mississippi State, MS USA 397622 Department of Geological Sciences, University of Florida, Gainesville, FL USA 32611 3 95 Jackson Street, Cambridge, MA USA 021404 Centro Ecological Akumal, Akumal, Quintana Roo, Mexico license Speleogenesis & Evolution of Karst Aquifers( )Abstract: Keywords: eolianites;

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last two decades has helped establish that eolian calcarenites are deposits that are tied thought that these carbonate eolianites produce eolianites on a transgression create features that are There has been a strong debate in the literature concerning to create a hard and resistant Table 1.

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Methodology Quintana Roo eolianites o they are called indicators of past positions of the fresh

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de facto Results cut bench on top of which are found subtidal facies deposits

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Discussion cut bench fronting the notch on the eolianites at northwest

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Conclusions

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Acknowledgements References SEPM Special Publication Association of Mexican Cave Studies Bulletin in Proceedings in Geological Society of America Special Paper in carbonate islands in Modern and Ancient Carbonate Eolianites: Sedimentology, Sequence in in Modern and Ancient Carbonate Eolianites: Special Publication in Unconformities and Porosity in Carbonate Strata: American Association of Petroleum Geologists Memoir in regions Marine Geology th in Geology in Geology



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Issue 11, 2011Speleogenesisand Evolution of Karst Aquifers IntroductionIn the past decade many papers have been published describing the development of karst features in the Bahamas (Pace et al., 1993; Mylroie and Carew, 1995; 1997; Harris et al., 1995; Mylroie et al., 1995; Carew and Mylroie, 1997; Mylroie and Vacher, 1999). Cave development in the Bahamas is zone, where fresh water and salt water mixing generate an aggressive state of dissolution potential, which initiates the At the top of the freshwater lens, phreatic pockets of dissolution are the antecedent conditions for the formation of banana holes (Harris et al., 1995). In the vadose zone, autogenic input of meteoric water into the epikarst initiates the development of pit caves, as described by Pace et al. (1993). Pit cave morphologies in eolianites: variability in primary structure control Paul J. Moore*, L. Don Seale, John E. Mylroie Martin, R. and Panuska, B., eds., 2004, Proceedings of the 11th Symposium on the Geology of the Bahamas and Other Carbonate Regions, Gerace Research Center, San Salvador Island, Bahamas, p. 145-155.Department of Geosciences, Mississippi State University, Starkville, MS 39759 by the authors. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license Speleogenesis & Evolution of Karst Aquifers )Abstract: Keywords: Editorial note:

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Moore P.J., Seale L.D., Mylroie J.E.PIT CAVE MORPHOLOGIES IN EOLIANITES: VARIABILITY IN PRIMARY STRUCTURE CONTROLThe genesis and geomorphology of phreatic dissolution been given much attention in the past; while only a small in the vadose zone (Pace et al., 1993; Mylroie and Carew, were conducted to assess the nature of karst development, particularly pit cave development, on a middle Pleistocene eolian ridge, Hog Cay. Hog Cay is located in the interior of San Salvador on the northwest side of the island. The work on Hog Cay resulted in the separation of pit caves into two independent cave types: vertical shafts and solution chimneys. The solution chimneys found on San Salvador are morphologically analogous to solution chimneys described in continental settings by White (1988). In continental settings, solution chimneys form by following tilted bedding planes, faults or fractures in the subsurface; however, on the seismically quiescent San Salvador platform, with its well-sorted carbonate that solution chimneys do develop in young rocks on tropical islands and are not restricted to continental settings or tectonic activity.SettingSan Salvador Island, Bahamas, is one of many islands that make up the Bahamian Archipelago. The island is located at 24 North Latitude, 74.5 West Longitude, approximately San Salvador Island is approximately 11 km wide and 19 km long. The total area is 161 km2 with a maximum elevation The island is composed mostly of eolian calcarenites, lakes, and low plains. All dunes currently above sea level are middle to late Quaternary in age. Those eolianites above 6m in elevation are above any past glacioeustatic sea-level highstand, and therefore above any previous elevated freshwater lens position, and have never experienced phreatic conditions. There are no surface streams on the island due to can be found, and an examination of water salinity versus location in relation to the ocean demonstrates the complex system of karst features hidden beneath present sea level. Hog Cay is an eolian ridge located north of the San Salvador the oldest stratagraphic unit exposed on the island (Carew

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Moore P.J., Seale L.D., Mylroie J.E. PIT CAVE MORPHOLOGIES IN EOLIANITES: VARIABILITY IN PRIMARY STRUCTURE CONTROL and Mylroie, 1995; 1997). No olitic rock has been found on Hog Cay. The ridge was chosen for exploration because of its potential in possessing advanced stages of karst dissolution. margin cave. It was discovered on the ridge in 1997 and was subsequently surveyed to be the second largest cave on the Types of Caves form as a result of intense dissolution on carbonate coasts at lens as a result of fresh water and salt water mixing. This creates a horizontal void that is parallel to the axis of the dune, characterized by blind pockets and dead-end tubular passages last interglacial sea-level highstand (Sangamon), which is associated with the deep-sea oxygen isotope substage 5e margin cave entrances are formed when slope retreat exposes Banana HolesHarris et al. (1995) describe banana holes as shallow phreatic voids that develop along the top of the freshwater lens, inland from the lens margin. In the Bahamas, this dissolution occurs in lowland plains, such that the voids are shallow. Collapse of the thin bedrock cap results in a depression with holes of today formed during the last interglacial highstand,

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Moore P.J., Seale L.D., Mylroie J.E.PIT CAVE MORPHOLOGIES IN EOLIANITES: VARIABILITY IN PRIMARY STRUCTURE CONTROL because of the less aggressive nature of the freshwater at the top of the lens, compared to conditions at the lens margin. Smart and Whitaker (1989) argue that carbonic acid, formed by dissolution of carbon dioxide generated by microorganisms and root respiration in the soil, provides the major chemical potential driving dissolution in most karst areas. Their argument implies that soil PCO2 increases with depth and density of the soil mat. They further their argument by describing the development of banana holes to be a result of: A direct effect of soil depth on PCO 1. 2 The persistence of decomposition at deeper, moister 2. sites. The tendency for organic material to erode from micro3. topographic highs and accumulate in lows. The tendency for vegetation to preferentially occupy 4. these accumulation sites. This model may apply to certain types of dissolution features found in the Bahamas, however, it does not address banana holes that are not yet open to the surface, or such voids that have a nearly intact roof with a small entrance at located at the bottom of the banana holes may contribute to further enlargement of an exposed banana hole, however, this would be a secondary process of the banana hole, independent of initial development. Pit CavesPit caves are dissolution features that transmit meteoric water from the epikarst to the top of the fresh-water lens or water table (Mylroie and Carew, 1995). As pit caves are open channels, they deliver the water at a much faster rate than of pit caves results from concentration of meteoric water in the epikarst, which exploits weak points in the carbonate rock to open a macroscopic pathway into the subsurface. Piracy of caves than the available water budget would appear to allow (Harris, et al., 1995). Until the work described here, no careful analysis of the initiating mechanism for pit cave development had been undertaken.Results and Discussion X-ray Diffraction AnalysisX-ray Diffraction (XRD) analysis shows that the predominant mineral present in cave wall rocks is aragonite with an appreciable amount of calcite (Tables 1 and 2). 5: B), where it is bounded top and bottom by regions of primary aragonite was present in the carbonate deposits. Two saturated regions in the vadose zone capillary water in the epikarst and a paleo-fresh water lens at the 5e sea level high stand allowed for inversion of primary aragonite to calcite, at the pit top and bottom, respectively. Wall rock throughout CK1 contains appreciable amounts of aragonite, much like the middle section of Graveyard Shaft. None of the samples taken from CK1, or any other solution chimney, show extensive inversion of aragonite to calcite (Table 2).Vertical ShaftsVertical Shafts show evidence of limited channeled surface point of insurgence. Typically, points of insurgence on Hog Cay have been observed to be attributed to micro-topographic lows that preferentially collect the meteoric water. Pohl (1955) central Kentucky, describe that vertical shafts are of a vadose origin where seepage through a caprock allows for a point of Sample ID Location Relative Abundance* GY -1 Ca>>Ar GY -2 Ar>Ca GY -3 Ca>>Ar CK1-1 Ar>Ca CK1-2 Ar>Ca CK1-3 Ar>Ca CK1-4 Ar>Ca relative abundances based on curve area estimates Table 1. XRD analysis of samples collected from a vertical shaft (Graveyard Shaft) and a solution chimney (CK1) on Hog Cay.

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Moore P.J., Seale L.D., Mylroie J.E. PIT CAVE MORPHOLOGIES IN EOLIANITES: VARIABILITY IN PRIMARY STRUCTURE CONTROL attack on the limestone. Mylroie and Carew (1995) explain this for an island setting stating that the epikarst, commonly with a calcrete crust, is the retardant factor allowing for discrete primary controlling factor of pit cave development is the result Vertical shafts form parallel to the effects of gravity and like their continental counterparts, show little if any morphological between elevation and the formation of vertical shafts; however, Pace et al. (1993) observes that most vertical shafts are located on dune ridges at elevations above 7 meters. These dune ridges have been described by Pace et al. (1993) to be of an olitic nature, where pit cave development rarely penetrates into lower bioclastic rock. Cay (Owls Hole formation) does show that extensive karst development can occur in bioclastic rock, and, in some cases, extend down to near sea level. Brucker et al. (1972) show that vertical shaft development is a complementation of the shaft, commonly as a supercriticalthat is undersaturated with respect to calcite. Brucker et al. (1972) argue that the near-perfect cylindrical nature of vertical shafts may be due to this supercriticalthe protuberance until only the vertical wall remains and the on Hog Cay, and elsewhere on San Salvador, correspond to support the process of vertical dissolution as observed by Pohl (1955), Pace et al., (1993) and Mylroie and Carew (1995).Solution Chimneys made between vertical shafts and solution chimneys, which have not been previously segregated in papers on Bahamian karst development. Unlike vertical shafts, solution chimneys show some appreciable morphological control due to bedding between vertical shafts and solution chimneys is based on the balance between hydrologic control and structural control of shaft morphology. In Whites study area of Kentucky and Sample ID Cave Name Sample Location Relative Abundance* 3HD-1 3 Holes Down Inside Entrance Ar>Ca 3HD-2 3 Holes Down ~4m inside pit Ar>Ca 3HD-3 3 Holes Down Near base of pit Ar>Ca RS-1 Rock Slide Inside Entrance Ar>Ca RS-2 Rock Slide Near base of pit Ar>Ca LB-1 Lone Bat Inside Entrance Ar>Ca LB-2 Lone Bat Near base of pit Ar>Ca relative abundances based on curve area estimatesTable 2. A BC

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Moore P.J., Seale L.D., Mylroie J.E.PIT CAVE MORPHOLOGIES IN EOLIANITES: VARIABILITY IN PRIMARY STRUCTURE CONTROL Pennsylvania, he was able to show that certain vadose-origin caves are controlled by faults and fractures, thus displaying an offset vertical incision into the subsurface. However on San Salvador, a tectonically stable platform, there are no apparent faults or fractures. Caputo (1995) described how eolian deposits can be sorted strata. Coarse-grained strata are often poorly-cemented and when exposed in weathered outcrops, they appear as microcemented and stand out as micro-ledges when exposed in It is postulated that in the subsurface, the coarse-grained, this case, cave passages tend to follow the dip of the foreset Exploration into solution chimneys on Hog Cay regularly end in a soil mat. In some instances, such as Rock Slide, A BCD

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Moore P.J., Seale L.D., Mylroie J.E. PIT CAVE MORPHOLOGIES IN EOLIANITES: VARIABILITY IN PRIMARY STRUCTURE CONTROL however the size of the passage is greatly reduced and human exploration is unachievable. In one exception, CK1, the margin cave (Majors Cave) and exploration is possible through It is hypothesized that once the connection between CK1 and Majors cave was attained, the soil plug that was in CK1 washed out, thus revealing the entire solution chimney. The connection between CK1 and Majors cave is an exciting discovery, especially since the cave survey indicates that it is the deepest dry cave (17.9 m), known to date, in the Bahamas. This connection, however, may be fortuitous as synchronicity and order of cave genesis have not been determined. The connection between CK1 and Majors Cave was further a three dimensional (3-D) map of observed karst features on all six caves in both the x and y direction, as well as the z direction. The spatial analysis of the observed caves show that, with the exception of CK1 and Majors Cave, each of the caves are completely independent of each other, and no apparent evidence show possible connections to other caves. constraints on possible cave connections, and sequence of cave development. X-ray Diffraction AnalysisWhile the aragonite rich bedrock appears to be the calcite found in Graveyard Shaft indicates that there are zones in which complete inversion of aragonite takes place. It is inferred that the aragonite undergoes inversion to calcite at the top of the shaft due to long residence times of meteoric water in the epikarst, and at the lower portion of the shaft because of not undergo inversion of aragonite to calcite due to the rapid transit time of vadose water along the shaft walls, which does not allow for the necessary residence time of meteoric water needed for the inversion. The re-crystallized calcite in the epikarst creates a calcrete crust, which acts as a caprock to focus autogenic water to a continental counterparts, vertical shafts propagate downward.Summary and Conclusion Pit caves found on Hog Cay are in the form of vertical shafts and solution chimneys. The micro-recesses and microledges as described by Caputo (1995) are ubiquitous in both the vertical shafts and solution chimneys. However, the vertical shafts have no indication of bedding control, which may be due

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Moore P.J., Seale L.D., Mylroie J.E.PIT CAVE MORPHOLOGIES IN EOLIANITES: VARIABILITY IN PRIMARY STRUCTURE CONTROL in areas of vertical shaft development. This is in spite of the fact that bedding orientation is the same as nearby solution chimneys, which show passage development along the foreset beds. The primary controlling factor in solution chimney morphology appears to be directly related to selective cemented, coarse-grained strata within the eolian calcarenites. strata. In this case, water is controlled by the well-cemented, At this time, it is unclear why vertical shafts, with no horizontal offset are able to form near solution chimneys. It is possible that selective cementation is not continuous throughout Hog Cay. It is also possible that the organic mat in the bottom of the shaft provides increased CO2 and therefore increased dissolution potential at the base. More extensive surveys of the karst features on Hog Cay may provide further insight into the primary controlling factors in pit cave development.Acknowledgements We would like to thank Dr. Donald T. Gerace, Chief of the Gerace Research Center, San Salvador, Bahamas for assistance allowed this project to be undertaken and was made possible by grants from the Mississippi State Academic Research Excellence program, as well as the Northeast Mississippi Daily Journal, and the Department of Geosciences, Mississippi State University. We would also like to thank bush are not forgotten.ReferencesBrucker, R. W., Hess, J. W., and White, W. B., 1972, Role of vertical shafts in the movement of ground water in carbonate aquifers: Caputo, M. V., 1995, Sedimentary architecture of Pleistocene eolian calcarenites, San Salvador Island, Bahamas, in Curran, H. A., and White, B., 63-76. Carew, J. L., and Mylroie, J.E., 1994, Geology and Karst of San Carew, J. L., and Mylroie, J. E., 1995, Quaternary tectonic stability of margin caves: Quaternary Science Reviews, v. 14, p. 145-153. Carew, J.L., and Mylroie, J.E., 1997, Geology of the Bahamas, in Vacher, H.L., and Quinn, T., eds., : Amsterdam, Elsevier Science, p. 91-139. Harris, J. G., Mylroie, J. E., and Carew, J. L., 1995, Banana Holes: unique karst features of the Bahamas: v. Recharge and aquifer response: Northern Guam Lens Aquifer, Guam, Mariana Islands: caves, dissolution cave development in carbonate platform: v. 15, p. 413-424. Mylroie, J. E., and Carew, J. L., 1995, Karst development on carbonate islands, in Budd, D. A., Saller, A. H., Harris, P. M., eds., p. 55-67. Mylroie, J.E., and Vacher, H.L., 1999, A conceptual view of carbonate island karst, in Palmer, A.N., Palmer, M.V., and Sasowsky, I.D., eds., p. 4858. Mylroie, J.E., Carew, J.L., and Vacher, H.L., 1995, Karst development in the Bahamas and Bermuda, in Curran, H.A., and White, B., eds., p. 251267. Pace, M.C., Mylroie, J. E., and Carew, J. L., 1993, Petrographic analysis of vertical dissolution features on San Salvador Island, Bahamas, in White, B., ed., Pohl, E. R., 1955, Vertical shafts in limestone caves, National No. 2. distribution of carbonate bedrock solution in the Bahamas, in Mylroie, J. E., ed., Proceedings, p. 313-321. A B C D


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