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Examples of the sediment layers, in stratigraphic order, encountered within the caves in this study.
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The glacially deranged karst topography of the Helderberg Plateau, central New York, contains glaciolacustrine lithofacies deposited at the end of the Wisconsin glaciation. Eight pre-glacial caves (Barrack Zourie Cave, McFail's Cave, Howe Caverns, Secret Caverns, Bensons Cave, Gage Caverns, Schoharie Caverns, and Caboose Cave), containing a unique...
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... the Schoharie sub- lobe, during the onset of the Late Wisconsin glaciation (Dineen, 1986). The lobes that covered the plateau entered the region from the northeast, as shown by drumlins and bedrock striations found in the study area that have a clear northeast-southwest trend (Mylroie and Mylroie, 2004). The glacial lobes deranged the landscape, altering it greatly. The landscape seen today is covered by drumlins, kames, glaciokarst, and buried glacial drainage basins, as well as other paleoglacial landforms. Dineen and Hanson (1985) proposed the Late Wisconsin glaciation ended in the region approximately 12,300 years ago, but the exact date is still highly debated. According to Muller and Calkin (1993), the Wisconsin is broken up into Early ( , 117.0– 64.0 ka), Middle ( , 64.0–23.0 ka), and Late ( , 23.0–11.9 ka) episodes. A glacial lake is a body of fresh water that is confined partly or entirely by a glacier or a geomorphic feature produced by a glacier (LaFleur, 1976). As mentioned earlier, there were a number of advance, retreat, and readvance phases associated with the Late Wisconsin glaciation in New York, resulting in the formation of multiple glacial lakes. The instability of glacial ice caused Glacial Lake Schoharie to have shorelines at varying elevations through- out the Late Wisconsin glaciation. The Woodstock ice margin was established by a halt in ice retreat from 18.2– 17.4 ka, according to Ridge (2004). Following the establishment of the ice margin, glacial meltwater began to flood the Schoharie Valley. As the stagnated glacial ice continued to melt and retreat toward the northeast, water levels continued to rise until a glacial lake was established with a shoreline at an elevation of 213 m (700 ft) above sea level (Dineen, 1986) (Fig. 6). The establishment of Glacial Lake Schoharie will be called stage one of three known stages of the glacial lake’s development. With the onset of the Middleburg readvancement at , 17.4 ka, based on Ridge (2004), advancing ice re-entered the Schoharie Valley and the greater Helderberg area until the ice reached the Catskill Front (Catskill Mountains). After reaching the Catskill Front, the glacier stagnated and once again began to retreat northward. While retreating, the glacier produced a vast amount of meltwater, resulting in the enlargement of several proglacial lakes (Dineen, 1986). Glacial Lake Schoharie enlarged considerably and established a shoreline between 354 and 366 m (1,160 and 1,200 ft) above sea level (Fig. 7), reaching stage two . With the establishment of the Delmar ice margin at , 16.2 ka (Ridge, 2004), water from Glacial Lake Schoharie drained to the northeast, through what is known as the Delanson spillway (LaFleur, 1969). The spillway fed the Delanson River, which eventually emptied into Glacial Lake Albany (LaFleur, 1976). The stage three shoreline of Glacial Lake Schoharie was established at 256 to 213 m (840 to 700 ft) above sea level (LaFleur, 1969; Dineen and Hanson, 1985) (Fig. 8). A total of 63 samples were collected and stored in sterilized plastic 35 mm film canisters for this study; three additional samples were collected from Barrack Zourie Cave by Kevin Dumont in 1995. Each sample was labeled with the cave, the location in the cave, and the stratum in the outcrop at that location. The samples collected for this study come from a wider suite of caves than those used in Mylroie (1984), and more sophisticated analysis techniques were conducted to determine how reliable Mylroie’s results were and how the samples compare to his data from Caboose Cave. The sample analyses were not intended to be diagnostic, but to provide a reconnaissance baseline to guide further research. To determine a general mineralogical content of the samples collected, x-ray diffraction (XRD) was utilized because of its ability to provide qualitative results in a cost- effective and time-efficient manner. All XRD analyses of powdered samples were conducted using the Rigaku Ultima III X-ray diffractometer and were interpreted using the MDI Jade 8 program. The XRD pattern for each sample was obtained using CuK a radiation with a wavelength of 1.541867 A ̊ . Scan speed was set for 2 degrees a minute with a scan step of 0.02 degrees, a scan axis of 2-theta/theta, and an effective scan range of 3.00–70.00 degrees. The laboratory analyses of samples to determine the mass of water in each sample, the mass of carbonates, and the mass of organics with the purpose of discerning a pattern among individual clastic units recovered from the ten caves in this study was inconclusive in terms of a recognizable pattern and can be seen in Weremeichik (2013). Although the laboratory results were inconclusive, X- ray diffraction yielded more conclusive information. The XRD data were not used to determine actual amounts of materials in a given sample; it was an assay of presence or absence. Table 1 shows the frequency of mineral content found to exist in each type of sample. Figure 4 shows typical examples of the vertical sequence of the sediment types found in the caves and used in Table 1. For example, the dark-grey/dark-brown clay unit had calcite in 62% of the samples, and the allogenic outwash unit had calcite in 40% of the samples. Together, these post-glacial lake sediments had 56% calcite occurrence. The light-grey clay unit had calcite in 100% of the samples, and the tan ‘‘white’’ clay unit had calcite in 75% of the samples. Together, the supposed glacial lake sediments had calcite in 81% of the samples. The Knox Cave and Westfall Cave sediment control samples, because those cave did not lie under the lake or postdated it, had calcite in only 33% of the samples. Brushite shows a different trend, being more common in the post-glacial sediments. During stage one of Glacial Lake Schoharie’s development, there would not have been any outlet for the water to escape by way of the Schoharie Valley. However, it would have been possible for the water in Glacial Lake Schoharie to drain north toward what is known today as the Mohawk Valley. But there is a problem with this idea, because during the Late Wisconsin the Mohawk Valley was occupied by the active Mohawk glacial lobe. The Mohawk glacial lobe, also referred to locally as the Mohawk Ice Block, filled the area between the neighboring Cobleskill and Barton Hill plateaus and acted as a plug, trapping glacial meltwater in the Schoharie Valley (LaFleur, 1969). Near the close of the Wisconsin glaciation, at least 50% of Glacial Lake Schoharie would have been covered by active glacial ice belonging to the Schoharie glacial sub-lobe (Dineen, 1986). As seen in Figures 6 and 9, during stage one (213 m) there would not have been a sufficient amount of water in Glacial Lake Schoharie to even partially inundate the caves of the Cobleskill Plateau and Barton Hill included in this study. In Figures 7 and 9 it can be seen that nearly all of the caves in the Cobleskill Plateau and Barton Hill are completely inundated by water from Glacial lake Schoharie during stage two ( , 360 m). Note that although the entrances to both McFail’s Cave and Gage Caverns were not inundated, the majority of the cave passages are over 30 m below the surface and would have been inundated based on their elevation relative to sea level and the stage two lake level. This would include inundation of locations where samples were collected for the study. The upper passages where samples were collected in Knox Cave would not have been inundated by glacial lake water due to their elevation, even if the lake had extended that far eastward, and so these samples acted as a control. Westfall Spring Cave, being post- glacial in origin, is not included in Figure 9. The clay sediments encountered in the caves fit the description of a varved sequence (Fig. 3). Varves are usually couplets of fine and coarse grained material (Neuendorf et al., 2011). These sediments do not show the alternating coarse-to-fine sequencing; they appear to only contain the fine sediments. A possible reason the sediments that compose the units are so uniform is that the insurgences and resurgences of the caves were most likely choked with glacially transported material, so only the smallest of sediments would be able to slowly percolate through the debris. These deposits are consistent with a laminar-flow regime expected for deposition deep in cave passages below a glacial lake. The white to tan clay deposits have an abrupt contact with overlying sand and gravel deposits (Fig. 3). Mylroie (1984) interpreted these coarse-grained sediments to be the result of ice retreat and re-establishment of the epigenic turbulent flow system in these caves. The same thing would have occurred during the draining of Glacial Lake Schoharie. The dark-brown clay was hypothesized by Mylroie (1984) to represent a surge of incoming sediment associated with clear-cutting following European settlement in the 1700s. The results here can neither prove nor disprove that speculation, but the dark-brown clays do represent what is being deposited in the caves today during flood cycles. The sequence of events that produced the sediment column of Figure 4 is presented in Figure 10. The Howe Caverns sediment section is especially instructive and is the thickest of all such sequences. While most caves have less than or equal to 1 m of the light-grey and tan ‘‘white’’ clay, Howe Caverns has over 2 m of section. This greater thickness is the result of Howe Caverns’ main stream passage being the lowest in elevation of all the cave passages studied, by approximately 30 meters (Fig. 9). Therefore, while lake surface elevations shifted vertically, Howe Caverns spent more time under Glacial Lake Schoharie than any other cave in the study, being inundated even during stage three . In addition, Figure 3 shows an interesting transition from a very amorphous white clay deposit at the base (next to the knife) to a progressively better layered ...
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... glaciers advanced and retreated across northeastern USA during the late Pleistocene, sediment and exposed bedrock were stripped from the cave-rich Helderberg Plateau in central New York State ( Fig. 1) and subsequently covered by allochthonous glacial sediment. The sediment was deposited on the surface of the plateau and in caves within the plateau. The glacial sediment deposited within the caves has been sheltered from surficial weath- ering and erosion, perhaps allowing for a more accurate record to be preserved. Interpretation and analysis of cave- sediment samples can assist in reconstructing the glacial surficial environment. In most glacially deranged landscapes, surficial deposits can be scarce and difficult to identify; this study focused and relied on samples collected from within caves. Specific horizons of sediment found within the caves in the area are thought to be associated with the existence of a glacial event (Mylroie, 1984; Palmer et al., 1991; Palmer et al., 2003). The work presented here re-interprets those earlier studies and classifies the unique cave sediments as being the result of a glacial lake inundating the caves. This lake, referred to as Glacial Lake Schoharie, is believed to have existed during the Late Wisconsin glacial period approximately 23.0–12.0 ka in the present-day Schoharie Valley in central New York (e.g., Dineen, 1986). To determine the nature of the surficial environment in the Schoharie Valley during the Late Wisconsin glacial period, multiple research trips were taken to select caves located in the Helderberg Plateau. From west to east, the caves in this study include: Barrack Zourie Cave (1 in Fig. 1), McFail’s Cave (2), Howe Caverns (3), the Secret- Benson Cave System (4 and 5), Gage Caverns (6), Westfall Spring Cave (7), Schoharie Caverns (8), Caboose Cave (9), and Knox Cave (10) (Figs. 1 and 2). As documented by Lauritzen and Mylroie (2000), U/Th dating of stalagmites demonstrates that the caves of the Schoharie Valley are older than the onset of the most recent glaciation and, in some cases, several glaciations reaching back 350 ka. The purpose of this study was to reconstruct the paleo- environment of a proglacial lake, Glacial Lake Schoharie, located primarily within Schoharie County, New York. The glacial lake is thought to have endured at least four readvances of the Mohawk and Hudson glacial lobes during the Woodfordian Substage of the Late Wisconsin glaciation; see Dineen (1986) for more detail on the nature of the readvances. The multiple readvances caused the shoreline of the lake, and hence its footprint, to be modified multiple times throughout its existence. The caves selected for investigation were chosen because of the known or suspected existence of what had been presumed to be glacially deposited clastics, in particular a characteristic white or tan clay that is sometimes varved (e.g., Mylroie, 1984; Dumont, 1995) (Figs. 3 and 4). It was also the purpose of this study to determine the composition of the ‘‘white’’ clay horizon, as well as the composition of other associated sediment horizons (Fig 4). Initial interpretation of Mylroie (1984) was that the sediments found in the caves were caused by stagnant sub- ice conditions during the last glacial maximum. Under these conditions, Mylroie (1984) thought that the stagnant water would soon saturate with CaCO 3 and that any further fine-grained particulate CaCO 3 introduced to the caves would not dissolve and could collect as a sediment deposit. There was no disagreement in the literature about this interpretation (e.g., Palmer et al., 2003), but it was recognized that caves in other areas of the state lacked these glacial sediments. The question became, what was unique about the caves in the Schoharie Valley. The presence of a glacial lake could create the same stagnant- water conditions in the underlying caves, and the lake’s footprint would explain the unique cluster of caves containing the glacial sediment. The caves located in the Helderberg Plateau formed in the Upper Silurian and Lower Devonian limestones of the Helderberg Group. The major caves and cave systems within the plateau, including the caves mentioned in this study, primarily formed within the thick-bedded Coeymans Limestone and the thinly bedded Manlius Limestone (Fig. 5). There has also been some cavern development within the Rondout Dolomite, as at Knox Cave and Baryte’s Cave (Mylroie, 1977; Palmer, 2009), but cavern development within this particular unit is usually limited to conduits with small cross-sectional areas. The caves and karst features of the Helderberg Plateau were created by epigenic processes providing surface runoff water an alternative to over-land flow paths, allowing water to travel more directly. The karst features of the Helderberg Plateau have been described as ‘‘one of the finest examples of glaciated karst in the country’’ (Palmer et al., 1991, p. 161). There has been extensive published work regarding the caves located in the Cobleskill Plateau and adjoining areas, such as that of Dumont (1995), Kastning (1975), Mylroie (1977), and Palmer et al. (2003). The glacial deposits within the caves were discussed by these authors, but the link of these sediments to a postulated glacial lake in this area had not been thoroughly investigated. Westfall Spring Cave was included in this study because its geologic context suggested it was post-glacial in origin; and therefore, it should not have a glacial sediment signature. Knox Cave was included because it is outside the footprint of Glacial Lake Schoharie. These two caves acted as controls for the sediment study. The last major Pleistocene glaciation to occur in New York was the Late Wisconsin glaciation. The Helderberg Plateau was covered by three lobes of glacial ice, the Mohawk lobe, the Hudson lobe, and the Schoharie sub- lobe, during the onset of the Late Wisconsin glaciation (Dineen, 1986). The lobes that covered the plateau entered the region from the northeast, as shown by drumlins and bedrock striations found in the study area that have a clear northeast-southwest trend (Mylroie and Mylroie, 2004). The glacial lobes deranged the landscape, altering it greatly. The landscape seen today is covered by drumlins, kames, glaciokarst, and buried glacial drainage basins, as well as other paleoglacial landforms. Dineen and Hanson (1985) proposed the Late Wisconsin glaciation ended in the region approximately 12,300 years ago, but the exact date is still highly debated. According to Muller and Calkin (1993), the Wisconsin is broken up into Early ( , 117.0– 64.0 ka), Middle ( , 64.0–23.0 ka), and Late ( , 23.0–11.9 ka) episodes. A glacial lake is a body of fresh water that is confined partly or entirely by a glacier or a geomorphic feature produced by a glacier (LaFleur, 1976). As mentioned earlier, there were a number of advance, retreat, and readvance phases associated with the Late Wisconsin glaciation in New York, resulting in the formation of multiple glacial lakes. The instability of glacial ice caused Glacial Lake Schoharie to have shorelines at varying elevations through- out the Late Wisconsin glaciation. The Woodstock ice margin was established by a halt in ice retreat from 18.2– 17.4 ka, according to Ridge (2004). Following the establishment of the ice margin, glacial meltwater began to flood the Schoharie Valley. As the stagnated glacial ice continued to melt and retreat toward the northeast, water levels continued to rise until a glacial lake was established with a shoreline at an elevation of 213 m (700 ft) above sea level (Dineen, 1986) (Fig. 6). The establishment of Glacial Lake Schoharie will be called stage one of three known stages of the glacial lake’s development. With the onset of the Middleburg readvancement at , 17.4 ka, based on Ridge (2004), advancing ice re-entered the Schoharie Valley and the greater Helderberg area until the ice reached the Catskill Front (Catskill Mountains). After reaching the Catskill Front, the glacier stagnated and once again began to retreat northward. While ...
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... set for 2 degrees a minute with a scan step of 0.02 degrees, a scan axis of 2-theta/theta, and an effective scan range of 3.00–70.00 degrees. The laboratory analyses of samples to determine the mass of water in each sample, the mass of carbonates, and the mass of organics with the purpose of discerning a pattern among individual clastic units recovered from the ten caves in this study was inconclusive in terms of a recognizable pattern and can be seen in Weremeichik (2013). Although the laboratory results were inconclusive, X- ray diffraction yielded more conclusive information. The XRD data were not used to determine actual amounts of materials in a given sample; it was an assay of presence or absence. Table 1 shows the frequency of mineral content found to exist in each type of sample. Figure 4 shows typical examples of the vertical sequence of the sediment types found in the caves and used in Table 1. For example, the dark-grey/dark-brown clay unit had calcite in 62% of the samples, and the allogenic outwash unit had calcite in 40% of the samples. Together, these post-glacial lake sediments had 56% calcite occurrence. The light-grey clay unit had calcite in 100% of the samples, and the tan ‘‘white’’ clay unit had calcite in 75% of the samples. Together, the supposed glacial lake sediments had calcite in 81% of the samples. The Knox Cave and Westfall Cave sediment control samples, because those cave did not lie under the lake or postdated it, had calcite in only 33% of the samples. Brushite shows a different trend, being more common in the post-glacial sediments. During stage one of Glacial Lake Schoharie’s development, there would not have been any outlet for the water to escape by way of the Schoharie Valley. However, it would have been possible for the water in Glacial Lake Schoharie to drain north toward what is known today as the Mohawk Valley. But there is a problem with this idea, because during the Late Wisconsin the Mohawk Valley was occupied by the active Mohawk glacial lobe. The Mohawk glacial lobe, also referred to locally as the Mohawk Ice Block, filled the area between the neighboring Cobleskill and Barton Hill plateaus and acted as a plug, trapping glacial meltwater in the Schoharie Valley (LaFleur, 1969). Near the close of the Wisconsin glaciation, at least 50% of Glacial Lake Schoharie would have been covered by active glacial ice belonging to the Schoharie glacial sub-lobe (Dineen, 1986). As seen in Figures 6 and 9, during stage one (213 m) there would not have been a sufficient amount of water in Glacial Lake Schoharie to even partially inundate the caves of the Cobleskill Plateau and Barton Hill included in this study. In Figures 7 and 9 it can be seen that nearly all of the caves in the Cobleskill Plateau and Barton Hill are completely inundated by water from Glacial lake Schoharie during stage two ( , 360 m). Note that although the entrances to both McFail’s Cave and Gage Caverns were not inundated, the majority of the cave passages are over 30 m below the surface and would have been inundated based on their elevation relative to sea level and the stage two lake level. This would include inundation of locations where samples were collected for the study. The upper passages where samples were collected in Knox Cave would not have been inundated by glacial lake water due to their elevation, even if the lake had extended that far eastward, and so these samples acted as a control. Westfall Spring Cave, being post- glacial in origin, is not included in Figure 9. The clay sediments encountered in the caves fit the description of a varved sequence (Fig. 3). Varves are usually couplets of fine and coarse grained material (Neuendorf et al., 2011). These sediments do not show the alternating coarse-to-fine sequencing; they appear to only contain the fine sediments. A possible reason the sediments that compose the units are so uniform is that the insurgences and resurgences of the caves were most likely choked with glacially transported material, so only the smallest of sediments would be able to slowly percolate through the debris. These deposits are consistent with a laminar-flow regime expected for deposition deep in cave passages below a glacial lake. The white to tan clay deposits have an abrupt contact with overlying sand and gravel deposits (Fig. 3). Mylroie (1984) interpreted these coarse-grained sediments to be the result of ice retreat and re-establishment of the epigenic turbulent flow system in these caves. The same thing would have occurred during the draining of Glacial Lake Schoharie. The dark-brown clay was hypothesized by Mylroie (1984) to represent a surge of incoming sediment associated with clear-cutting following European settlement in the 1700s. The results here can neither prove nor disprove that speculation, but the dark-brown clays do represent what is being deposited in the caves today during flood cycles. The sequence of events that produced the sediment column of Figure 4 is presented in Figure 10. The Howe Caverns sediment section is especially instructive and is the thickest of all such sequences. While most caves have less than or equal to 1 m of the light-grey and tan ‘‘white’’ clay, Howe Caverns has over 2 m of section. This greater thickness is the result of Howe Caverns’ main stream passage being the lowest in elevation of all the cave passages studied, by approximately 30 meters (Fig. 9). Therefore, while lake surface elevations shifted vertically, Howe Caverns spent more time under Glacial Lake Schoharie than any other cave in the study, being inundated even during stage three . In addition, Figure 3 shows an interesting transition from a very amorphous white clay deposit at the base (next to the knife) to a progressively better layered light-grey clay in which the individual layers get thicker upwards to the contact with more ordinary cave sediments. This transition can be interpreted to indicate initial clay deposition stage two , when the Howe Caverns stream passage would have been , 100 m below the lake’s surface at , 360 m. Sediment transport by laminar flow into the cave would have been slow and quite isolated from seasonal changes, indicated by the lack of rhythmical layering in the ‘‘white’’ clay deposit. As lake level lowered to the 256 m level during stage three , the Howe Caverns main stream passage would have been merely meters below the lake’s surface and more likely to record the seasonal changes in water and sediment addition to the lake, as demonstrated by the light-grey clay. The upward thickening may record the final transition of Howe Caverns out of the lake footprint as the lake drained away. The sediment analyses were for the most part inconclusive. Based on the X-ray diffraction results, the glacial sediments are more likely to have calcite in them, which is consistent with the stagnant water conditions proposed by Mylroie (1984). The mass-loss experiments were less convincing, with a great deal of variation within the data and no consistent pattern. Mylroie (1984) had reported a very high solubles content for the Caboose Cave white clay, and while this study did replicate that result to an extent, the high solubles content was not consistent across the other caves in the study. It is useful to note that Knox Cave, acting as a pre-glacial control cave, has much less variation in its samples than the caves under the Glacial Lake Schoharie footprint. The sediment analysis was done as a reconnaissance, to determine if more work would be worthwhile in the future, and it was not central to the final interpretation of the sediment’s glaciolacustrine origin. The caves suspected to have been inundated by glacial lake water and, therefore, to have collected fine-grained lake sediment do not show any statistical correlation between samples collected (see Weremeichik, 2013). But, as seen in Figure 3, it is apparent that physical similarities between the samples collected exist. These physical similarities can be correlated with their mineral’s color and grain size. It was originally hypothesized that the sediment in the caves may have been deposited during a retreat phase of glaciation resulting from stagnant ice- covered conditions (e.g., Mylroie, 1984). This hypothesis was thought to be true because it explains how the fine- grained sediment was deposited in the caves. This could not have happened if there had been turbid or even transition- ally laminar flow through the caves. Ice cover would have created the necessary stagnant conditions. The glacial-lake hypothesis presented here also would create stagnant conditions, but in an environment where the associated fine-grained sediment could more easily enter the cave. Glacial Lake Schoharie endured multiple retreats and readvances of glacial ice, in part, by being insulated and protected by a layer of stagnated glacial ice. During retreat phases of glacial activity, new glacial meltwater carrying glacial-derived sediment must have been delivered to the lake, which subsequently filtered into the caves below. The analyses of the sediments themselves are consistent with the glacial-lake hypothesis. They are extremely fine- grained, very low in organics (Weremeichik, 2013), and with a measurable soluble content of calcite. They are visually striking when observed in the field and are easily recognized. They are, to date, known only from within the footprint of Glacial Lake Schoharie. This final aspect is important, as the deposits were originally considered by earlier workers (e.g., Mylroie, 1984) to be sub-ice deposits. The failure to find such deposits elsewhere in the Helderberg Plateau or in other glaciated karst regions was very problematic. Everyone who saw the deposits in situ agreed with their glacial rock-flour origin (e.g., Palmer et al., 2003). The use of the Glacial Lake Schoharie footprint to explain these deposits as not sub-ice, but sub- lake deposits, explains the failure to ...
Citations
... Terrestrial secondary carbonate deposits (e.g., speleothems and tufas) associated with exposed limestones often display annual laminae, which can provide valuable paleoclimatic records (e.g., Kano et al., 2004;Baker et al., 2008;Hori et al., 2008;Zhang et al., 2008;Kawai et al., 2009). Cave rhythmites, which are carbonate-containing laminated deposits, are a potential paleoclimatic archive (e.g., Drew and Cohen, 1980;Bull, 1981;Schönlaub et al., 1991;Delannoy et al., 2009;Weremeichik and Mylroie, 2014;Ballesteros et al., 2017). ...
... The irregular spatial distribution of the Omi rhythmite (Figs. 2, 3B, D), its allochthonous occurrence in the surrounding limestone, and its association with limestone breccia (Fig. 3C, D) indicate that it was most likely a cave-filling deposit. Fine-grained laminated deposits have been reported from limestone caves around the world (e.g., Drew and Cohen, 1980;Bull, 1981;Schönlaub et al., 1991;Delannoy et al., 2009;Weremeichik and Mylroie, 2014;Ballesteros et al., 2017), as well as from paleo-caves (e.g., Schönlaub et al., 1991;Dandurand et al., 2011;Evans and Soreghan, 2015;Nehme et al., 2015). In addition, such cavefilling deposits have been reported from the late Paleozoic seamounttype limestone in Japan (e.g., Yanagimoto, 1973;Conodont Research Group, 1974;Koike et al., 1974). ...
Terrestrial carbonate deposits associated with exposed limestone are potential recorders of paleoclimates and karst paleohydrology. Here we examine the depositional process of the Omi rhythmite layers, which filled karstic cavities in the Pennsylvanian (middle Kasimovian) section of the Omi Limestone, a seamount-type limestone in central Japan. The laminated rhythmite layers accompanied signatures of subaerial exposure, including Microcodium, which indicates a seasonally dry climate in the late Kasimovian. The rhythmite layers are calcareous, low in siliciclastic content, and composed of millimeter-scale laminae. In each lamina, the grain size decreases and the δ¹⁸O value increases upwards. We inferred that each lamina corresponds to a single cave flood event followed by a dry and evaporative interval. ⁸⁷Sr/⁸⁶Sr ratios of the rhythmites are almost identical to the ratio of the surrounding limestone, but clearly lower than the Kasimovian seawater ratio. This indicates that the rhythmites and the surrounding limestone were subjected to the same post-depositional alteration, before the subduction of the seamount in the Guadalupian (middle Permian). The sedimentary and isotopic features of the Omi rhythmite and occurrence of Microcodium support repetition of wetting and drying on an equatorial Panthalassan island during the Pennsylvanian (late Carboniferous).
... Paleoenvironmental records corresponding to Marine Isotope Stages (MIS) 4e3 are relatively scarce in glaciated mountains, mainly due to glacier erosion associated to the Last Glacial Maximum (LGM) of MIS 2. In areas made of limestone or another soluble rock, karst caves often preserve abundant additional paleoenvironmental evidence sheltered from surface weathering (H€ auselmann, 2013). Cave evidence can be compared with surface landforms and sedimentary logs in order to reconstruct the past environmental evolution of a territory, improving our understanding on glacial advances and retreats (Mylroie and Mylroie, 2004;Bo ci c et al., 2012;Weremeichik and Mylroie, 2014). ...
... Glaciers can inject sediments in cave passages located at more than 1 km depth (Audra et al., 2002), as well as in shallow caves influenced by glacial outwash and located at distances of over 1000 km from the icefield (Mylroie, 1984). Since these sediments result from the glacial erosion of limestone, they are mostly formed of carbonate-rich silt, the so-called "glacial rock-flour" or "glacial milk" (Bo ci c et al., 2012;Weremeichik and Mylroie, 2014). In addition, cave detrital aggradation may also include allochthonous cobbles and gravels derived from the erosion of any lithology outcropping in the catchment area (Audra et al., 2002;Ballesteros et al., 2017). ...
... However, if glaciers reach the bottom of fluvial valleys, karst springs can be blocked by till, thus triggering inundations in the endokarst (Skoglund et al., 2010). During these floods, glacial carbonate silt decants forming rhythmic slackwater deposits related to sedimentary changes in underground lakes (Weremeichik and Mylroie, 2014;Ballesteros et al., 2017). ...
In glaciated areas, the environmental evolution before MIS 2 is usually poorly constrained mainly due to the later glacial erosion during the global Last Glacial Maximum (LGM). However, in carbonate areas, karst caves can preserve records of pre-LGM paleoenvironment. We studied a cave (1350 m altitude) to establish the paleoenvironmental evolution of a glaciated karst area in Picos de Europa (SW Europe). For this objective, a glacial reconstruction, cave sedimentology analyses, and macro-and micromammal remains are com bined with ten UeTh, OSL and AMS 14 C ages. The paleo-glacial reconstruction indicates glaciers descended down to 810e1040 m of altitude covering an area of 36.18 km 2 in the surroundings of Covadonga Lakes during the glacial local maximum, with the equilibrium line altitude located at 1524 ± 36 m. The geomorphological study of the cave and the UeTh and OSL dates reveal the presence of three allochthonous alluvial sediment sequences at 132e135, 98e60 and ca. 36 ka. These last two sequences would come from the erosion of fluvioglacial sediments including teeth fragments of Pliomys coronensis (¼P. lenki), an unusual species in high areas of NW Spain during the Upper Pleistocene. In addition, remains of chamois (Rupicapra pyrenaica) dated in 37e33 cal ka BP constitutes the oldest evidence of chamois above 800 m asl in the region. All the presented data indicate the development of alpine glacier-free areas covered by fluvioglacial sediments at ca. 1450 m altitude at 98e60 and 37e33 ka, corresponding to glacial retreat stages.
... In these areas, low temperatures limit the vegetation productivity, reducing soil pCO 2 , acid organics and drip water saturation (Lauritzen and Skoglund, 2013;Zhou et al., 2015). Alpine caves support important speleothems and ice records in glaciated areas of South Europe during the Quaternary, such as the Alps and Pyrenees ( Miorandi et al., 2010;Wackerbarth et al., 2012;Weremeichik and Mylroie, 2014). Further, the presence of remains of troglobitic/stygobitic fauna in alpine caves indicates past climate fluctuations and glacial ice extensions ( Eme et al., 2014). ...
Alpine caves have attracted considerable geomorphological, paleoenvironmental and hydrogeological interest since climate, glaciations, relief uplift, fluvial incision and karst aquifer control their evolution. In the Atlantic Margin of the Iberian Peninsula, Picos de Europa mountains is among of the most important karst areas of the World containing some of the deepest caves explored today. In addition, these mountains represent a reference site for the study of the Last Glacial Cycle in the SW of Europe. This work aims to reconstruct the Pliocene-Quaternary evolution of this region based on geomorphological and geochronological research (U/Th and Al/Be) carried out in four alpine caves. Cave geomorphological mapping evidences that 12 km of studied caves are made up of 47% vadose canyons and shafts, 45% phreatic/epiphreatic conduits organised in six cave levels, and 7% breakdown-modified passages. Their deposits are characterized by speleothems, including flowstones, that represent ancient cave pavements, fluvial terrace deposits with allochthonous clasts, slackwater deposits related to cave floods, and debris deposits produced by breakdown. One ²⁶ Al/ ¹⁰ Be burial age indicates a minimum age of 2.1 ± 0.5 Ma for the caves origin, allowing estimation of the mountain uplift at 0.15–0.25 mm·a ⁻¹ since the Late Pliocene. Twenty-eight new ²³⁴ U/ ²³⁰ Th ages and another six previous speleothem ages give ages ranging from MIS 8 to 1. The speleogenetic model comprises six phases of regional evolution. Phase 1: main development of cave levels with SE-directed phreatic flow in the NW of Picos de Europa, in a karst partially or totally covered by the detrital Permian-Mesozoic cover, presently eroded. Phase 2: erosion of the Permian-Mesozoic cover and onset of vadose conditions before 260 ka, in a karst-affected by fluvial captures. Phase 3: cave infill during 220–145 ka, probably caused by the erosion of Stephanian detrital outcrops. Phase 4: erosion of cave infill during 125–45 ka. Phase 5: apparent pause in the speleothem formation during 45–25 ka related to dry and cold regional conditions. Phase 6: reactivation of the speleothem precipitation since 25 ka. Regional climate, fluvial incision and the ancient presence of detrital outcrops at the surface appear to have been the main factors that controlled the cave evolution and regional geomorphological evolution throughout Pliocene and Quaternary times.
... The depositional environment and periodic lamination of the rhythmite (Section 5.1) could be related to the seasonal melting of the glaciers that would provide water and sediments to the cave mainly during the summer. With respect to the mineralogy (Section 5.2), high carbonate content (65-80%) should be related to glacial flour produced by glacial erosion of limestone (Quinif and Maire, 1998;Weremeichik and Mylroie, 2014). Besides, the recognized allochthonous minerals should be transported by glaciers and/or by waters resulting from melting in higher areas of the Western massif of Picos de Europa (Fig. 8). ...
... For the first time, the obtained results demonstrate that the glaciers controlled cave filling in Picos de Europa during the early Pleistocene, as it was previously described in caves from the Rocky Mountains, Alps, and Scandinavia Peninsula (e.g., Audra et al., 2006;Rykwalder, 2007;Plan et al., 2009;Lundberg et al., 2010;Lauritzen and Skoglund, 2013). The interpretation of the cave rhythmite of Picos de Europa as glacial varves is plausible according to previous studies (e.g., Quinif and Maire, 1998;Weremeichik and Mylroie, 2014), being necessary new studies to demonstrate the annual periodicity of its lamination. ...
Laminated slackwater deposits have been identified in many karst caves related to fluvial and lacustrine sedimentation. However, sedimentological evidence rarely supports a glacial origin for these deposits, which was proposed by previous studies. The Torca La Texa shaft is located in a glaciokarst area that comprises numerous slackwater-type deposits, piled up in fining-upward sequences. A basal sandy erosive layer and millimeter-sized laminated rhythmite with interbedded flowstone characterize these sequences. Fining-upward layers of carbonate silt, clay, and minor quartz sand deposited in flooded conduits define the rhythmite lamination. The presence of allochthonous minerals indicates that the rhythmite sediment comes from the glacial erosion of nearby carbonate mountains. Two ²³⁴U/²³⁰Th radiometric ages dated the rhythmite deposits around 109 and 95 ka, coinciding with relative cold periods included in the MIS 5d-c. These cold periods were marked by a high annual seasonality, immediately after the glacial local maximum extension, in agreement with a varve-type deposit. The combination of these sedimentological mineralogical, geomorphological and paleoclimate information indicates that the rhythmite should be introduced into the studied cave during the summer melting of the glaciers, which produced the recharge of the karst aquifer, triggering cave floods. In addition, punctual glacier collapses would also have their imprint in the slackwater sequences with thicker, coarser and erosive sand deposits and the spring blocking by glaciers may have promoted floods inside the cave. Therefore, the studied rhythmite can be interpreted as glacial varves decanted during the relatively cold climate conditions.
... Other possible depositional environments for the fine laminated sediments are less compatible with the properties and physical location of these deposits. For instance, somewhat similar sediments have been reported from water-filled subglacial caves (Larsen et al., 1987;Valen et al., 1997;Ward et al., 2003;Weremeichik and Mylroie, 2014) but in all of these examples the point of deposition was close to the cave entrance. In the case of Weybridge Cave it is unlikely that the sediment comprising these deposits could be transported deep into the intricate network of passageways in the absence of through-flowing conditions. ...
Optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) dating were applied to cave sediments that were protected from the Marine Isotope Stage 2 (MIS-2) advance of the Laurentide Ice Sheet (LIS) in the Champlain Valley of western Vermont. Evidence indicates that these sediments were derived from a subaerial landscape, requiring that the ice margin was north of the Champlain Valley when they were deposited. A basal sandy gravel was deposited during MIS-4 (∼68 ka), sand near the middle of the composite stratigraphy was deposited during MIS-3 (∼55 ka), and a layer of coarse sand in the stratigraphically highest position was deposited at the onset of MIS-2 (∼35 ka). The youngest age constrains advance of the LIS south of the international border early in MIS-2, and is combined with other available evidence to constrain ice advance rates over the 12 000 years leading up to the Last Glacial Maximum. Rates estimated from limiting ages were relatively slow (25 ma⁻¹) as the ice ascended the adverse slope out of the St. Lawrence Lowland, increased as the margin advanced through the Champlain Valley, perhaps aided by subglacial bed deformation or ice streaming, and were fastest (∼100 ma⁻¹) as the margin approached the terminal moraine position.
... Many published works exist which investigate different aspects of the caves located in the Cobleskill Plateau e.g. [1][2][3][4][5][6] and references therein. It is the purpose of this research to determine the location and existence of an abandoned trunk passage. ...
... It has been proposed that in some areas of the Schoharie Valley region, an excess of 30 m of glacial till lies between the bedrock surface and the ground surface [7]. According to Palmer et al. [7] the 30 m between the bedrock and ground surface is thought to be comprised of material such as glacial till, glacial lake deposits [5], and drumlins. The known depths to which the soils described below persist in the region is approximately 1.5 m but it is possible that they could extend to roughly 2 m below the ground surface [13,14]. ...
The Cobleskill Plateau of central New York, part of the greater Helderberg Plateau, is comprised of Silurian and Devonian limestone. This area displays caves and karst landforms subsequently altered by glaciation. The glacially mantled and in-filled pre-existing karst topography of the area was caused by hydrologic changes that determined current karst flow paths. Determining the nature of the antecedent topography, and the location of cave passages, is critical to a complete hydrologic analysis of the Cobleskill Plateau. Two gravity traverses were conducted along traverses near Cobleskill, New York using a Worden Gravity Meter with the intent to validate the subsurface location of an occluded abandoned trunk passage connecting Howe Caverns and McFails Cave. To clarify, the term ‘abandoned’ is meant as an identifier that the passage is no longer utilized as the primary flow path and is only utilized by flowing water during periods of moderate to high discharge. The importance of the existence or absence of the abandoned trunk passage is to increase the understanding of subsurface geology, potential hazards, and controls on pre-glacial groundwater flow in the region. The findings of this study conclude that subsurface anomaly sources do exist at anticipated locations which were believed to contain the passage in question. The study demonstrates that it is possible to identify this passage through the use of gravity surveys. However, the exact shape and size of the anomaly cannot be definitively determined by this study, as the true depth to bedrock could not be determined. Though it is possible to roughly estimate passage dimensions based on a knowledge of the traversable, upstream and downstream passages. The data collected in this study can be fit to various models which can be interpreted to support the existence of a void beneath the two traverses. Further exploration of the subsurface karst systems in the region is needed to determine the exact nature of the anomaly sources.
... Glacial sediment as clays are present in older, pre-glacial caves such as Morris Cave and Aeolus Bat Cave (Quick 2010), where they may represent fines that settled out under ice or lake cover. No analysis of these sediments has been done to determine if they are similar to those reported from the Helderberg Plateau by Weremeichik and Mylroie (2014). Bobcat Cave appears to contain glacial till that was extruded into the cave (Quick 2010); Bob's Birthday Cave has a similar deposit (J. ...
Dissolutional cave development in the New England and eastern New York area is primarily in Cambro-Ordovician marbles that extend in a north-south band along the western boundary of Connecticut, Massachusetts, and Vermont, and similarly in the eastern-most portion of New York. Some Precambrian marbles, and some Ordovician carbonates are also found in this area. Maine has karst areas, but they are remote, low-lying, and poorly understood. Cave development appears to have been mostly post-glacial, with a few relict (pre-glacial) large caves (e.g. Aeolus Bat Cave, Morris Cave), and several large caves that are likely combination caves that while active in the current deranged hydrology, have passages inherited from pre-glacial times (e.g. Vermonster, Carthusian and Merlins caves). Joint activation by isostatic rebound following ice withdrawal, coupled with large glacial lake discharges, are argued to be the prime initiator of cave development. The caves that result are commonly shallow, and vulnerable to removal by the next glaciation, indicating a cyclic nature to cave development and destruction, avoided only by the larger, deeper or fortuitously placed cave systems. A general lack of glacial sediments in smaller caves is a good indicator that many caves are post-glacial, though some examples exist of pre-glacial caves containing sediment (e.g. Weybridge Cave). Cave science has been sparse and sporadic in this region, but a recent wave of papers, coupled with new discoveries of major caves, indicates that this region will be a greater participant in speleology in the future.
... At first glance the statistics of these caves would make them appear pre-glacial; the length of Glen Park Labyrinth is less than 1-km shorter than Barrack Zourie Cave (Engel 1996), a clearly pre-glacial cave with post-glacial modification (Dumont 1995). Caves interpreted to be post-glacial, such as Westfall Spring Cave (Weremeichik and Mylroie 2014) of the Helderbergs, as well as passages within pre-glacial caves interpreted to be post-glacial overprints appear to have small cross-sectional areas. Arguments given by cavers of the northeastern US, following Palmer (1991), claim that while caves can form to traversable sizes in the time since deglaciation, larger passages should be pre-glacial or sub-glacial in origin to reach an appreciable cross-sectional area (e.g. ...
Flat-lying Ordovician limestones form a band around the Adirondack Mountains, separating the Grenville marble caves of those mountains from the caves developed in Cambro-Ordovician marbles to the east and southeast, and from caves in Siluro-Devonian carbonates to the south (deformed) and southwest (undeformed). This cave region is understudied and little scientific work has been done, although a limestone pavement project and a maze cave examination have been published. Caves of small size, in agreement with post-glacial deranged drainage (Schroeders Pants Cave, Houghs Cave), have been identified, as well as caves of possible pre-glacial or englacial origin (Mitchells Cave). The major cave features of this region are the large and extensive maze caves along the Black and Perch rivers, multi-kilometer systems of post-glacial origin, the largest of which, the Glen Park Labyrinth, is now relict and abandoned. These caves, in tune with the post-glacial deranged drainage of major rivers, indicate that high, sustained discharges can create large maze caves within a portion of the post-glacial time window. Houghs Cave has historical importance as a stop on the Underground Railway for escaped slaves in the pre-Civil War era.
In this chapter, notable glaciokarsts of the world are presented. Geographical location, geologic and tectonic settings, climatic conditions, glaciation phases as well as surface and underground karst landforms are presented about each selected region. Obviously, the areal extent, the degree of exploration and the amount of publicly available information are different in each case. Historically, the first glaciokarst studies were based on the Alps, the Pyrenees, the Dinaric Alps and the British Isles, and they have remained in the focus since then. Hence, these regions are presented here in more detail, but even these presentations can be considered only short overviews. Some other glaciokarst terrains, such as Scandinavia or the Rocky Mountains, have also been thoroughly studied but later in history; nevertheless, there are abundant internationally available publications about them. Certain parts of the Balkan Peninsula, the Apennines or even Anatolia received high attention more recently and novel methods have been used to investigate their glaciokarst terrains. The Carpathians and the Appalachians, which are also discussed in this chapter, are extensively studied mountains in general, but glaciokarsts occupy a relatively small proportion in them. On the other hand, there are still regions, which are difficult to access, where glaciokarsts are poorly explored, and/or the available literature is limited (or the publications are only in Russian, for instance). Some of them, namely, the Altai Mountains, the Greater Caucasus, the Tian Shan, the Pamir and the Patagonian archipelago, are also briefly presented here. Finally, it is noted that our selection does not contain all glaciokarsts of the world because it is beyond the scope of this chapter.
The longest and largest caves of the northeastern region (Barrack Zourie Cave, Howe Caverns, McFails Cave, Skull Cave and Thunder Hole) are found in the Helderberg Plateau of central New York. Broad areal exposure of Helderberg Group limestones, gentle dip SSW at 1°–2°, and down-dip incision of those limestones by surface drainage has created a hydrological setting conducive to large cave formation. Interaction of strike and dip with groundwater release points has created parallel and unconnected down-dip caves above Fox Creek to the east, but integrated and subsequently partitioned strike-oriented caves above Cobleskill Creek to the west. Glaciation has deranged this landscape, particularly in the west where the Cobleskill Creek has been infilled with glacial sediment, backflooding the downstream portions of the McFails and Barrack Zourie cave systems; backflooding has also been severe to the east at Skull Cave, where joint activation due to isostatic rebound has allowed exploitation by floodwaters to create a large rectilinear maze superimposed upon a dendritic cave pattern. A south-flowing tributary valley of Cobleskill Creek has been subdivided by drumlins into a series of large closed depressions that drain to Barrack Zourie and McFails caves. Deranged surface drainage enters many pre-glacial caves by young, post-glacial input routes, and independent small post-glacial caves have developed. Pre-glacial age for the large systems has been demonstrated to be at least 350 ka by U/Th dating, and the perseverance of the pre-glacial drainage pattern through multiple glaciations suggests that the cave hydrology was established pre-Pleistocene.
