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1
Liu, Qi, Zichen He, Takeshi Naganuma, Ryosuke Nakai, Luz María Rodríguez, Rafael Carreño, and Franco Urbani. "Phylotypic Diversity of Bacteria Associated with Speleothems of a Silicate Cave in a Guiana Shield Tepui." Microorganisms 10, no. 7 (July 11, 2022): 1395. http://dx.doi.org/10.3390/microorganisms10071395.
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The diversity of microorganisms associated with speleological sources has mainly been studied in limestone caves, while studies in silicate caves are still under development. Here, we profiled the microbial diversity of opal speleothems from a silicate cave in Guiana Highlands. Bulk DNAs were extracted from three speleothems of two types, i.e., one soft whitish mushroom-like speleothem and two hard blackish coral-like speleothems. The extracted DNAs were amplified for sequencing the V3–V4 region of the bacterial 16S rRNA gene by MiSeq. A total of 210,309 valid reads were obtained and clustered into 3184 phylotypes or operational taxonomic units (OTUs). The OTUs from the soft whitish speleothem were mostly affiliated with Acidobacteriota, Pseudomonadota (formerly, Proteobacteria), and Chloroflexota, with the OTUs ascribed to Nitrospirota being found specifically in this speleothem. The OTUs from the hard blackish speleothems were similar to each other and were mostly affiliated with Pseudomonadota, Acidobacteriota, and Actinomycetota (formerly, Actinobacteria). These OTU compositions were generally consistent with those reported for limestone and silicate caves. The OTUs were further used to infer metabolic features by using the PICRUSt bioinformatic tool, and membrane transport and amino acid metabolism were noticeably featured. These and other featured metabolisms may influence the pH microenvironment and, consequently, the formation, weathering, and re-deposition of silicate speleothems.
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Surić, Maša, Nada Horvatinčić, Axel Suckow, Mladen Juračić, and Jadranka Barešić. "Isotope records in submarine speleothems from the Adriatic coast, Croatia." Bulletin de la Société Géologique de France 176, no. 4 (July 1, 2005): 363–72. http://dx.doi.org/10.2113/176.4.363.
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Abstract Isotope studies, using 14C dating, δ13C and δ18O measurements, were performed at eight speleothems taken from three submerged caves situated along the eastern Adriatic coast, Croatia. The speleothems were taken from 17 m to 38.5 m depth below mean sea level. The samples consist of four stalagmites and four stalactites in position of growth, covered with marine biogenic overgrowth, and the length of speleothems ranges from ~80 mm to ~190 mm. The youngest (surface) and the oldest (base) layers of speleothems were radiocarbon dated and the 14C ages range from 21,600 cal B.P. to 37,000 yr B.P. During that period the global sea level was more than 40 m below the recent one, so presently submerged objects were under the subaerial conditions necessary for speleothem deposition. 14C ages of the youngest layer range from 21,600 to 32,200 cal B.P. for different submerged speleothems. This indicates the time when the speleothem growth ceased, most probably due to flooding of the cave with either fresh or brackish water. Speleothem growth during the Last Glacial Maximum (30–19 kyr ago) and different time of growth cessation for the different speleothem samples suggest that climate change was not the reason for cessation of deposition. Samples for δ13C and δ18O measurements were taken from six submerged speleothems with sampling distances of ca. 5–10 mm from the surface to the base of speleothems. Most of the δ13C values are in the range from −10.5‰ to −8.5‰, with few exceptions to −6‰. These values are typical for Dinaric karst, and very different values for marine biogenic overgrowth indicate that no isotopic exchange took place during the submerged period. δ18O values range from −6.7‰ to −4.1‰. A weak correlation between δ13C and δ18O values indicates possible kinetic isotope fractionation during the calcite precipitation. If the δ18O record is interpreted as climatic signal, it suggests similar climatic conditions for the late Pleistocene and the Holocene, especially no significant differences in temperature and/or moisture transport.
3
Johnson, Kathleen R. "Tales from the Underground: Speleothem Records of Past Hydroclimate." Elements 17, no. 2 (April 1, 2021): 93–100. http://dx.doi.org/10.2138/gselements.17.2.93.
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Geochemical records from speleothems have significantly advanced our understanding of natural climate variability over the last ~600,000 years. Speleothems are sensitive recorders of past changes in hydroclimate because they can be precisely dated and contain multiple hydrologically sensitive geochemical proxies. Oxygen isotope records from speleothems tell us about the timing and mechanisms of past changes in precipitation amount, temperature, atmospheric circulation, and/or global monsoon intensity. Variations in speleothem carbon isotope ratios or trace element concentrations reflect changes in local water balance, vegetation, and karst hydrology. Speleothem paleoclimate records represent a window into the past that can provide crucial information for understanding how anthropogenic climate change and natural climate variability will impact future water resources on Earth.
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Meckler, A. Nele, Hubert Vonhof, and Alfredo Martínez-García. "Temperature Reconstructions Using Speleothems." Elements 17, no. 2 (April 1, 2021): 101–6. http://dx.doi.org/10.2138/gselements.17.2.101.
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Methods for reconstructing past temperatures from speleothems have only recently been developed. Advances in quantitative temperature proxies for speleothems are now allowing critical knowledge gaps to be filled, given the outstanding age control and wide geographical distribution of the speleothem archive. The methods of reconstructing temperatures from speleothems are diverse: they rely on concepts from geochemistry, biology, and physics, and are based on different aspects of speleothems, including water inclusions, calcite, and organic molecules. Combining the different approaches makes temperature reconstructions more robust, affords further insights into the methodologies, and provides constraints on other climate variables.
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Pawlak, J., H. Hercman, P. Sierpień, P. Pruner, M. Gąsiorowski, A. Mihevc, N. Zupan Hajna, P. Bosák, M. Błaszczyk, and B. Wach. "Estimation of the durations of breaks in deposition – speleothem case study." Geochronometria 47, no. 1 (January 1, 2020): 154–70. http://dx.doi.org/10.2478/geochr-2020-0022.
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Abstract Speleothems provide one of the most continuous terrestrial archives. However, due to changing conditions in temperature/humidity or the chemistry of percolating water, sedimentation breaks (hiatuses) and erosional events are possible and are commonly recorded in speleothems. Sedimentation breaks with durations longer than the resolution of the studied record should be considered in potential speleothem age-depth models. The most classic and reliable solution to the problem is the independent construction of age-depth models for the parts of speleothems separated by the hiatuses. However, in some cases, it is not possible to obtain a sufficient number of dating results for reliable age-depth model estimation. In such cases, the problem can be solved by the application of other sources of chronological information. Here, based on a few speleothem examples, an alternative approach – oxygen isotopic stratigraphy – is used to estimate the chronology for the parts of speleothems where there is not enough chronological information for classic age-depth models. As a result, the deposition break duration can be estimated.
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Wendt, Kathleen A., Xianglei Li, and R. Lawrence Edwards. "Uranium–Thorium Dating of Speleothems." Elements 17, no. 2 (April 1, 2021): 87–92. http://dx.doi.org/10.2138/gselements.17.2.87.
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Speleothems are important timekeepers of Earth’s climate history. A key advantage of speleothems is that they can be dated using U–Th techniques. Mass spectrometric methods for measuring U and Th isotopes has led to vast improvements in measurement precision and a dramatic reduction in sample size. As a result, the timing of past climate, environment, and Earth system changes can be investigated at exceptional temporal precision. In this review, we summarize the principles and history of U–Th dating of speleothems. Finally, we highlight three studies that use U–Th dated speleothems to investigate past changes to the Asian monsoon, constrain the timing of sociopolitical change in ancient civilizations, and develop a speleothem-based calibration of the 14C timescale.
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Hodge, Ed, Janece McDonald, Matthew Fischer, Dale Redwood, Quan Hua, Vladimir Levchenko, Russell Drysdale, Chris Waring, and David Fink. "Using the 14C Bomb Pulse to Date Young Speleothems." Radiocarbon 53, no. 2 (2011): 345–57. http://dx.doi.org/10.1017/s0033822200056605.
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Three modern speleothems were sampled at high resolution for radiocarbon analysis to identify their bomb-pulse signatures and to construct chronologies. Each speleothem exhibited a different 14C response, presumed to be related to site characteristics such as vegetation, temperature, rainfall, depth below the surface, and water pathway through the aquifer. Peak 14C activity for WM4 is 134.1 pMC, the highest cited thus far in the literature and suggestive of a lower inertia at this site. Dead carbon fractions for each stalagmite were calculated and found to be relatively similar for the 3 speleothems and lower than those derived from Northern Hemisphere speleothems. An inverse modeling technique based on the work of Genty and Massault (1999) was used to estimate soil carbon residence times. For each speleothem, mean soil 14C reservoir ages differed greatly between the 3 sites, ranging from 2–6.5 to 32–46 yr.
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Atsawawaranunt, Kamolphat, Laia Comas-Bru, Sahar Amirnezhad Mozhdehi, Michael Deininger, Sandy P. Harrison, Andy Baker, Meighan Boyd, et al. "The SISAL database: a global resource to document oxygen and carbon isotope records from speleothems." Earth System Science Data 10, no. 3 (September 14, 2018): 1687–713. http://dx.doi.org/10.5194/essd-10-1687-2018.
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Abstract. Stable isotope records from speleothems provide information on past climate changes, most particularly information that can be used to reconstruct past changes in precipitation and atmospheric circulation. These records are increasingly being used to provide “out-of-sample” evaluations of isotope-enabled climate models. SISAL (Speleothem Isotope Synthesis and Analysis) is an international working group of the Past Global Changes (PAGES) project. The working group aims to provide a comprehensive compilation of speleothem isotope records for climate reconstruction and model evaluation. The SISAL database contains data for individual speleothems, grouped by cave system. Stable isotopes of oxygen and carbon (δ18O, δ13C) measurements are referenced by distance from the top or bottom of the speleothem. Additional tables provide information on dating, including information on the dates used to construct the original age model and sufficient information to assess the quality of each data set and to erect a standardized chronology across different speleothems. The metadata table provides location information, information on the full range of measurements carried out on each speleothem and information on the cave system that is relevant to the interpretation of the records, as well as citations for both publications and archived data. The compiled data are available at https://doi.org/10.17864/1947.147.
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Pazdur, Anna, Mieczysław F. Pazdur, Jacek Pawlyta, Andrzej Górny, and Michał Olszewski. "Paleoclimatic Implications of Radiocarbon Dating Of Speleothems from the Cracow-Wieluń Upland, Southern Poland." Radiocarbon 37, no. 2 (1995): 103–10. http://dx.doi.org/10.1017/s0033822200030538.
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We report preliminary results of a long-term systematic study intended to gather paleoclimatic records from precisely dated speleothems. The research project is limited to speleothems deposited in caves of the Cracow-Wieluń Upland, the largest and best-explored karst region in Poland, covering ca. 2900 km2 with >1000 caves. Speleothem samples were selected from collections of the Geological Museum of the Academy of Mining and Metallurgy in Cracow. Radiocarbon dates of these samples from ca. 45–20 ka bp almost exactly coincide with age range of the Interplenivistulian. A break in speleothem formation between ca. 20 and 10 ka bp may be interpreted as a result of serious climatic deterioration associated with the maximum extent of the last glaciation. We observed differences among 14C, U/Th and AAR dating results. Changes of δ13C and δ18O in speleothems that grew between ca. 30 and 20 ka bp may be interpreted as changes of paleoclimatic conditions.
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Medley, Joseph J., Jennifer J. M. Hathaway, Michael N. Spilde, and Diana E. Northup. "Looking for Microbial Biosignatures in All the Right Places: Clues for Identifying Extraterrestrial Life in Lava Tubes." Applied Sciences 14, no. 15 (July 25, 2024): 6500. http://dx.doi.org/10.3390/app14156500.
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Lava caves are home to a stunning display of secondary mineral speleothems, such as moonmilk and coralloids, as well as highly visible microbial mats. These features contain diverse and under-characterized groups of bacteria. The role of these bacteria in the formation of secondary mineral speleothems is just beginning to be investigated. The lava caves of the Big Island of Hawai`i and in El Malpais National Monument, New Mexico (USA), share many morphologically similar speleothems. This study focused on investigating the overlap in bacteria across a wide range of speleothems in these two geographically distant sites. Through scanning electron microscopy (SEM) and 16S rRNA gene analysis, we found that Hawaiian caves have a greater alpha diversity and beta diversity separated by cave and speleothem type. Many Actinobacteriota were in higher abundance in New Mexico caves, while Hawaiian caves contained more bacteria that are unclassified at the genus and species level. Discovering the diversity in bacteria in these secondary speleothems will assist in identifying cave secondary mineral formations that may be good candidates for finding life on extraterrestrial bodies.
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Comas-Bru, Laia, and Sandy P. Harrison. "SISAL: Bringing Added Value to Speleothem Research." Quaternary 2, no. 1 (February 1, 2019): 7. http://dx.doi.org/10.3390/quat2010007.
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Isotopic records from speleothems are an important source of information about past climates and, given the increase in the number of isotope-enabled climate models, are likely to become an important tool for climate model evaluation. SISAL (Speleothem Isotopes Synthesis and Analysis) have created a global database of isotopic records from speleothems in order to facilitate regional analyses and data-model comparison. The papers in this Special Issue showcase the use of the database for regional analyses. In this paper, we discuss some of the important issues underpinning the use of speleothems and how the existence of this database assists palaeoclimate research. We also highlight some of the lessons learned in the creation of the SISAL database and outline potential research going forward.
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Pons-Branchu, Edwige, Bruno Hamelin, Jacques Brulhetet, and Laurent Bruxelles. "Speleothem rupture in karst: tectonic or climatic origin? U-Th dating of rupture events in Salamandre Cave (Gard, southeastern France)." Bulletin de la Société Géologique de France 175, no. 5 (September 1, 2004): 473–79. http://dx.doi.org/10.2113/175.5.473.
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Abstract Caves are relatively protected from the main external erosional factors. Therefore, they constitute potentially reliable places for long-term conservation of continental history. Moreover their secondary carbonated deposits, the speleothems, can be dated precisely on the 0-500 ka time-scale using U-series isotopes measured by thermo-ionisation mass spectrometry (TIMS). Tectonic events (tectonic displacements and earthquakes) may change cave morphology and induce speleothem breaking or displacement as has been shown by previous studies performed mainly in Italy [Forti et Postpischl, 1984; Postpischl et al., 1991 for example]. Nevertheless, collapses of speleothems observed today in caves are difficult to interpret as their origin may be linked to several other natural processes. We studied the Aven de la Salamandre cave located in southeastern France (Gard), an area between the Cevennes fault and the Nîmes fault, where evidence of Quaternary vertical movements was previously described. However, this region is not considered to be a seismic active zone. The Aven de la Salamandre cave is characterized by numerous broken speleothems. Some of them are very large and a lot of them are covered by growth of new calcite or new speleothem generation. We report here 13 TIMS U/Th analysis performed on two broken speleothems recovered by second generation calcite growth. Dating results are discussed through time corrections due to detrital content of calcite. In the first sequence, a 7 ± 0.35 ka fracture event is identified. In the second sequence, the age of the breakdown is between 1.1 ± 0.1 and 6.3 ± 2 ka. These events could thus be contemporary. Hypotheses for the origin of this fracture event are presented and discussed: (i) karstic catastrophic event due to intense climatic changes or to cavity collapse (break down of hanging wall, gravity, landslide…); (ii) co-seismic ruptures. The first conclusion of this study is that these collapse episodes in the Aven de la Salamandre cave cannot be due to the direct effect of an earthquake or climatic event. Only indirect effects of flooding (by mobilization of the argillaceous components of the floor and consecutive destabilization of the speleothems growing upon it) or earthquake effects (more likely by local effects than by wave front passage) are privileged. By comparing our dating with regional destructive known events (in other karsts, in cliffs and scarps), dated by relative chronology, we are lead to propose a regional generalized event precisely dated here at 7 ka. This second conclusion doesn’t contradict the presence of unbroken speleothems older than 100 ka found in other caves in the neighborhood as local effects is one of the predominant factors relative to speleothem stability. As a final conclusion, this paper promotes the use of speleothems as reliable datable tools for assessing regional stability problems (sensitivity to seismic hazards, to destructive intense climatic events…) as is done for paleoclimatic reconstruction.
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Lauriol, B., D. C. Ford, J. Cinq-Mars, and W. A. Morris. "The chronology of speleothem deposition in northern Yukon and its relationships to permafrost." Canadian Journal of Earth Sciences 34, no. 7 (July 1, 1997): 902–11. http://dx.doi.org/10.1139/e17-075.
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In the northern Yukon there is a significant group of limestone caves in an area that was not glaciated during the Quaternary. Permafrost appears to have played an important role in restricting calcite speleothem deposition in the caves. U/Th dating and stable isotopic studies indicate that the deposits form two distinct groups, a first group younger than 350 ka, and a second group older than the 350 ka BP limit of the conventional U/Th alpha spectrometric dating method. Two large samples from the second group yield sequences of magnetic declinations and inclinations with reversed and normal polarity, perhaps from the Tertiary. The pollen content of five speleothems, the modes of calcite deposition, and stable isotopic analyses indicate that the speleothems were deposited under a cold regime. It is suggested that the ancient speleothems were deposited at a time when permafrost was absent, during the later Tertiary or at the beginning of the Quaternary period. The establishment and maintenance of permafrost throughout the Quaternary has prevented the formation of younger speleothems, except at a few cave entrances where the active layer may have deepened during interglacials.
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Heidke, Inken, Denis Scholz, and Thorsten Hoffmann. "Quantification of lignin oxidation products as vegetation biomarkers in speleothems and cave drip water." Biogeosciences 15, no. 19 (October 4, 2018): 5831–45. http://dx.doi.org/10.5194/bg-15-5831-2018.
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Abstract. Here we present a sensitive method to analyze lignin oxidation products (LOPs) in speleothems and cave drip water to provide a new tool for paleo-vegetation reconstruction. Speleothems are valuable climate archives. However, compared to other terrestrial climate archives, such as lake sediments, speleothems contain very little organic matter. Therefore, very few studies on organic biomarkers in speleothems are available. Our new sensitive method allows us to use LOPs as vegetation biomarkers in speleothems. Our method consists of acid digestion of the speleothem sample followed by solid-phase extraction (SPE) of the organic matter. The extracted polymeric lignin is degraded in a microwave-assisted alkaline CuO oxidation step to yield monomeric LOPs. The LOPs are extracted via SPE and finally analyzed via ultrahigh-performance liquid chromatography (UHPLC) coupled to electrospray ionization (ESI) and high-resolution Orbitrap mass spectrometry (HRMS). The method was applied to stalagmite samples with a sample size of 3–5 g and cave drip water samples with a sample size of 100–200 mL from the Herbstlabyrinth-Advent Cave in Germany. In addition, fresh plant samples, soil water, and powdered lignin samples were analyzed for comparison. The concentration of the sum of eight LOPs (Σ8) was in the range of 20–84 ng g−1 for the stalagmite samples and 230–440 ng L−1 for the cave drip water samples. The limits of quantification for the individual LOPs ranged from 0.3–8.2 ng per sample or 1.5–41.0 ng mL−1 of the final sample solution. Our method represents a new and powerful analytical tool for paleo-vegetation studies and has great potential to identify the pathways of lignin incorporation into speleothems.
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EENSAAR, JAAN, TÕNU PANI, MIKK GAŠKOV, HOLAR SEPP, and KALLE KIRSIMÄE. "Stable isotope composition of hypogenic speleothem calcite in Kalana (Estonia) as a record of microbial methanotrophy and fluid evolution." Geological Magazine 154, no. 1 (December 11, 2015): 57–67. http://dx.doi.org/10.1017/s0016756815000928.
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AbstractAeronian (Silurian Period) carbonate rocks in Kalana quarry in central Estonia contain cave and fracture structures filled with calcitic speleothem precipitates of atypical composition. Calcite crystals in dolomitized limestone cave walls have diverse shapes (equant-blocky, bladed and fibrous), but most of the cave walls and speleothems are covered with an up to 10 cm thick crust of microcrystalline botryoidal calcite. The morphology of precipitates suggests their formation in low hydrodynamic conditions in water supersaturated with calcite. Calcite in speleothems is associated with the mineralization of sulphur-bearing minerals, such as pyrite and abundant barite. Unlike that of speleothem calcite, the stable isotope composition of authigenic calcite shows extreme depletion in 13C and large variations in δ13CPDB from –11 to –56‰, whereas the δ18OPDB values range from –5 to –12‰, suggesting calcite precipitation from a 13C-depleted carbon source supplied by microbially mediated anaerobic oxidation of methane and/or other hydrocarbons at elevated temperatures (up to 70°C). Systematic variation in the δ13CPDB and δ18OPDB values of layered precipitates indicates a change from an initially biogenic methane source to an either thermogenic methane or hydrocarbon source in the low-temperature hydrothermal fluid. Calcite speleothems in Kalana possibly developed at the mixing front of sulphate-rich seawater or groundwater and low-temperature methane-bearing hydrothermal fluids in the phreatic zone of a hypogenic-hydrothermal (karst) system.
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Ifandi, E., B. Tsikouras, and K. Hatzipanagiotou. "Contribution to the evolution of the Perama Cave (Ioannina, NW Greece)." Bulletin of the Geological Society of Greece 47, no. 1 (December 21, 2016): 255. http://dx.doi.org/10.12681/bgsg.10939.
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This study includes the description of thirty three speleothem types, which were found in the Perama cave, Ioannina, NW Greece, according to the international literature, along with the interpretation of their formation, for the first time in Greece. The detailed study of these speleothems coupled with observations of the way of their formation and their spatial distribution enabled us to suggest that the Perama cave evolved through a sequence of episodes that include dissolution of the host Senonian limestone, collapse of its roof formations, as well as alternating events of formation of stalactitic- and stalagmitic-type speleothems with excess water flow and/or flooding, which resulted in the development of stream formations
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Goslar, Tomasz, Helena Hercman, and Anna Pazdur. "Comparison of U-Series and Radiocarbon Dates of Speleothems." Radiocarbon 42, no. 3 (2000): 403–14. http://dx.doi.org/10.1017/s0033822200030332.
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The paper presents a comparison of U-series and radiocarbon dates of speleothems collected in several caves in central and southern Europe and southeast Africa. Despite a large spread of dates, mainly due to contamination with younger carbon, the group of corresponding 14C and 230Th/U ages of speleothem samples seems to be coherent with the previous suggestion of large deviation between the 14C and the absolute time scale between 35 and 45 ka BP. This agrees with the result of frequency analysis of published 14C and 230Th/U ages of speleothem.
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Vansteenberge, Stef, Sophie Verheyden, Hai Cheng, R. Lawrence Edwards, Eddy Keppens, and Philippe Claeys. "Paleoclimate in continental northwestern Europe during the Eemian and early Weichselian (125–97 ka): insights from a Belgian speleothem." Climate of the Past 12, no. 7 (July 5, 2016): 1445–58. http://dx.doi.org/10.5194/cp-12-1445-2016.
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Abstract. The last interglacial serves as an excellent time interval for studying climate dynamics during past warm periods. Speleothems have been successfully used for reconstructing the paleoclimate of last interglacial continental Europe. However, all previously investigated speleothems are restricted to southern Europe or the Alps, leaving large parts of northwestern Europe undocumented. To better understand regional climate changes over the past, a larger spatial coverage of European last interglacial continental records is essential, and speleothems, because of their ability to obtain excellent chronologies, can provide a major contribution. Here, we present new, high-resolution data from a stalagmite (Han-9) obtained from the Han-sur-Lesse Cave in Belgium. Han-9 formed between 125.3 and ∼ 97 ka, with interruptions of growth occurring at 117.3–112.9 and 106.6–103.6 ka. The speleothem was investigated for its growth, morphology and stable isotope (δ13C and δ18O) composition. The speleothem started growing relatively late within the last interglacial, at 125.3 ka, as other European continental archives suggest that Eemian optimum conditions were already present during that time. It appears that the initiation of Han-9 growth is caused by an increase in moisture availability, linked to wetter conditions around 125.3 ka. The δ13C and δ18O proxies indicate a period of relatively stable conditions after 125.3 ka; however, at 120 ka the speleothem δ18O registered the first signs of regionally changing climate conditions, being a modification of ocean source δ18O linked to an increase in ice volume towards the Marine Isotope Stage (MIS) 5e–5d transition. At 117.5 ka, drastic vegetation changes are recorded by Han-9 δ13C immediately followed by a cessation of speleothem growth at 117.3 ka, suggesting a transition to significantly dryer conditions. The Han-9 record covering the early Weichselian displays larger amplitudes in both isotope proxies and changes in stalagmite morphology, evidencing increased variability compared to the Eemian. Stadials that appear to be analogous to those in Greenland are recognized in Han-9, and the chronology is consistent with other European (speleothem) records. Greenland Stadial 25 is reflected as a cold/dry period within Han-9 stable isotope proxies, and the second interruption in speleothem growth occurs simultaneously with Greenland Stadial 24.
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Burstyn, Yuval, Ron Shaar, Jonathan Keinan, Yael Ebert, Avner Ayalon, Miryam Bar-Matthews, and Joshua M. Feinberg. "Holocene wet episodes recorded by magnetic minerals in stalagmites from Soreq Cave, Israel." Geology 50, no. 3 (November 22, 2021): 284–88. http://dx.doi.org/10.1130/g49383.1.
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Abstract This study demonstrates the feasibility of speleothem magnetism as a paleo-hydrology proxy in speleothems growing in semi-arid conditions. Soil-derived magnetic particles in speleothems retain valuable information on the physicochemical conditions of the overlying soil, and changes in bedrock hydrology. Yet, the link between magnetic and isotopic proxies of speleothems has been only partly established. We reveal strong coupling between the inflow of magnetic particles (quantified using the magnetic flux index, IRMflux) and δ13C in two Holocene speleothems from Soreq Cave (Israel). The stalagmite record spans from ca. 9.7 to ca. 5.4 ka, capturing the warm-humid conditions associated with the early Holocene and the transition to mid-Holocene wet-dry cycles. Extremely low IRMflux during the early Holocene, indicating minimal contribution from the overlying soil, is accompanied by anomalously high δ13C (approaching bedrock values) hypothesized to be caused by high rainfall and soil erosion. By contrast, IRMflux during the mid-Holocene covaries with the saw-tooth cyclicity of δ13C and δ18O, interpreted as rapid fluctuations in rainfall amount. The peaks in IRMflux precede the negative (wet) δ13C peaks by ~60–120 yr. The apparent lag is explained as a rapid physical translocation of overlying soil particles via groundwater (high IRMflux) as a response to increasing rainfall, compared with slower soil organic matter turnover rates (10–102 yr).
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Kukuljan, Lovel, Franci Gabrovšek, and Vanessa E. Johnston. "Low-Calcium Cave Dripwaters in a High CO2 Environment: Formation and Development of Corrosion Cups in Postojna Cave, Slovenia." Water 13, no. 22 (November 11, 2021): 3184. http://dx.doi.org/10.3390/w13223184.
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Speleothems have proven to be one of the most reliable terrestrial archives for palaeoclimate research. However, due to the complexity of karst systems, long-term monitoring and high-resolution analyses of the cave atmosphere and water geochemistry have become essential to better constrain the factors that control calcite growth and how geochemical palaeoclimate proxies are encoded into speleothems. While calcite precipitation incorporates the palaeoclimate signals into the speleothem fabric, certain conditions in caves can favour dissolution, which may form hiatuses or even destroy these signals. In extreme cases, in-cave dissolution by dripwater can form cup-shaped features (i.e., corrosion cups), which were the main focus of this study. The study site in Postojna Cave, Slovenia was investigated through cave climate monitoring and drip and cup water sampling, which took place during 2017–2021. We found that the cups are fed by low-calcium drips as the consequence of the thin rock overburden above the cave. Due to the specific configuration of the airflow pathways, the study site accumulates high levels of CO2 (>10,000 ppm), which shifts low-calcium dripwater into undersaturation. This causes dissolution on the rock surfaces and speleothems on the cave floor. The results of this study have broader significance in addressing the suitability of cave environments and speleothems used in paleoclimate research.
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Sengupta, P., J. Sanwal, N. L. Dudwadkar, S. C. Tripathi, and P. M. Gandhi. "Adsorption of actinides within speleothems." Mineralogical Magazine 80, no. 5 (August 2016): 765–80. http://dx.doi.org/10.1180/minmag.2016.080.013.
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AbstractStalagmites and stalactites, as observed within natural caves, may develop inside geological repositories during constructional and post-operational periods. It is therefore important to understand actinide sorption within such materials. Towards this, experimental studies were carried out with 233U, 238Np (VI), 238Np (IV), 239Pu and 241Am radiotracers using natural speleothem samples collected from the Dharamjali cave of the Kumaon Lesser Himalayas, India. Petrological/mineralogical studies showed that natural speleothems have three general domains: (1) columnar calcite; (2) microcrystalline calcite; and (3) botryoidal aragonite – each with ferruginous materials. Results showed that all domains of speleothems can take up >99% actinides, irrespective of valence state and pH (1–6 range) of the solution. However, distribution coefficients were found to be at a maximum in aragonite for most of the actinides. Such data are very important for long-term performance and safety assessments of the deep geological repositories planned for the disposal of high-level nuclear wastes.
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Pacton, M., S. F. M. Breitenbach, F. A. Lechleitner, A. Vaks, C. Rollion-Bard, O. S. Gutareva, A. V. Osintcev, and C. Vasconcelos. "The role of microorganisms in the formation of a stalactite in Botovskaya Cave, Siberia – paleoenvironmental implications." Biogeosciences 10, no. 9 (September 27, 2013): 6115–30. http://dx.doi.org/10.5194/bg-10-6115-2013.
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Abstract. Calcitic speleothems in caves can form through abiogenic or biogenic processes, or through a combination of both. Many issues conspire to make the assessment of biogenicity difficult, especially when focusing on old speleothem deposits. This study reports on a multiproxy analysis of a Siberian stalactite, combining high-resolution microscopy, isotope geochemistry and microbially enhanced mineral precipitation laboratory experiments. The contact between growth layers in a stalactite exhibits a biogenic isotopic signature; coupled with morphological evidence, this supports a microbial origin of calcite crystals. SIMS δ13C data suggest that microbially mediated speleothem formation occurred repeatedly at short intervals before abiotic precipitation took over. The studied stalactite also contains iron and manganese oxides that have been mediated by microbial activity through extracellular polymeric substance (EPS)-influenced organomineralization processes. The latter reflect paleoenvironmental changes that occurred more than 500 000 yr ago, possibly related to the presence of a peat bog above the cave at that time. Microbial activity can initiate calcite deposition in the aphotic zone of caves before inorganic precipitation of speleothem carbonates. This study highlights the importance of microbially induced fractionation that can result in large negative δ13C excursions. The microscale biogeochemical processes imply that microbial activity has only negligible effects on the bulk δ13C signature in speleothems, which is more strongly affected by CO2 degassing and the host rock signature.
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Pacton, M., S. F. M. Breitenbach, F. A. Lechleitner, A. Vaks, C. Rollion-Bard, O. S. Gutareva, A. V. Osinzev, and C. Vasconcelos. "The role of microorganisms on the formation of a stalactite in Botovskaya Cave, Siberia – palaeoenvironmental implications." Biogeosciences Discussions 10, no. 4 (April 8, 2013): 6563–603. http://dx.doi.org/10.5194/bgd-10-6563-2013.
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Abstract. Calcitic speleothems in caves can form through abiogenic, biogenic, or a combination of both processes. Many issues conspire to make the assessment of biogenicity difficult, especially when focusing on old speleothem deposits. This study reports a multiproxy analysis of a Siberian stalactite, combining high-resolution microscopy, isotope geochemistry and microbially enhanced mineral precipitation laboratory experiments. The contact between growth layers in a stalactite exhibits a biogenic isotopic signature; coupled with morphological evidence this supports a microbial origin of calcite crystals. SIMS δ13C data suggest that microbially mediated speleothem formation occurred repeatedly for short intervals before abiotic precipitation took over. The studied stalactite also contains iron and manganese oxides that have been mediated by microbial activity through extracellular polymeric substances (EPS)-influenced organomineralization processes. The latter reflect palaeoenvironmental changes that occurred more than 500 000 yr ago, possibly related to the presence of a peat bog above the cave at that time. Microbial activity can initiate calcite deposition in the aphotic zone of caves before inorganic precipitation of speleothem carbonates. This study highlights the importance of microbially induced fractionation that can result in large negative δ13C excursions. The micro-scale biogeochemical processes imply that microbial activity has only negligible effects on the bulk δ13C signature in speleothems, which is more strongly affected by CO2 degassing and the hostrock signature.
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Kashiwaya, Kenji, Timothy C. Atkinson, and Peter L. Smart. "Periodic Variations in Late Pleistocene Speleothem Abundance in Britain." Quaternary Research 35, no. 2 (March 1991): 190–96. http://dx.doi.org/10.1016/0033-5894(91)90066-e.
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AbstractTemporal change in the growth of speleothems in the United Kingdom during the past 150,000 years is shown to be related to the insolation variation by the Milankovitch theory. The speleothem data compiled by Gordon et al. (1989. Quarternary Research 31, 14–26) have two Milanokovitch frequencies: the ca. 40,000-yr period related to change in the earth's obliquity and the ca. 20,000-yr period related to the precession of the equinoxes. The abundance of speleothem growth was, in general, large during the last interglaciation and small during the last glaciation. In both periods, however, speleothem abundance was greater during periods of strong insolation and less during weak insolation.
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Frisia, S., A. Borsato, R. N. Drysdale, B. Paul, A. Greig, and M. Cotte. "A re-evaluation of the palaeoclimatic significance of phosphorus variability in speleothems revealed by high-resolution synchrotron micro XRF mapping." Climate of the Past 8, no. 6 (December 14, 2012): 2039–51. http://dx.doi.org/10.5194/cp-8-2039-2012.
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Abstract. Phosphorus (P) is potentially a very important environmental proxy in speleothem palaeoclimate reconstructions. However, the transfer of P to a speleothem seems to vary between cave sites. Therefore, it is important to investigate the source of P and the way it is incorporated into a speleothem on a site-by-site basis before it can be used as a robust palaeoclimate proxy. In this paper, the distribution of P in one modern and two Early Pliocene speleothems formed in coastal caves on Christmas Island (Indian Ocean) and the Nullarbor Plain (southern Australia) is investigated using microscopy and ultra-high resolution chemical mapping. Phosphorus has been found to be both incorporated in the lattice and present as diverse P-rich phases. Monitoring data from Christmas Island suggest that co-precipitation of P-rich phases occurs when "prior calcite precipitation" decreases following recharge, even if the drip rate decreases. Microbial mediation may also play a role, which complicates a direct climate relationship between P and hydrology. We find that some P-enriched layers contain dissolution features, with possible involvement of microbial mats which colonise pores during reduced drip rates associated with prolonged dry spells. In the two Early Pliocene speleothems the relationship between P and microbial laminae is clearer. Both petrographic and chemical data suggest that phosphorus-rich phases in the microbial laminae mark intervals of reduced drip rates, which may indicate dry intervals during the otherwise wet palaeoclimate of the Early Pliocene. We develop a speleothem distribution coefficient for phosphorus (SKP) rather than the thermodynamic partition coefficient (KP) to account for the presence of crystalline phosphate inclusions. SKP describes P enrichment in speleothems regardless of the process, as similar mechanisms of phosphate co-precipitation may be in operation in biotic and abiotic conditions. The most important implication of our study is that variability in P concentration may be related to diverse processes which can be recognized through petrographic observations and chemical mapping. In particular, there may not be a direct relation between an increase in P concentration and seasonal infiltration as has been found in some previous studies, especially if the source of this element is not the labile phosphate released through leaching during seasonal vegetation dieback in temperate climates.
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Vaks, Anton, Miryam Bar-Matthews, Avner Ayalon, Bettina Schilman, Mabs Gilmour, Chris J. Hawkesworth, Amos Frumkin, Aaron Kaufman, and Alan Matthews. "Paleoclimate reconstruction based on the timing of speleothem growth and oxygen and carbon isotope composition in a cave located in the rain shadow in Israel." Quaternary Research 59, no. 2 (March 2003): 182–93. http://dx.doi.org/10.1016/s0033-5894(03)00013-9.
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AbstractHigh-resolution 230Th/234U ages and δ18O and δ13C compositions of speleothems in Ma’ale Efrayim Cave located to the east of the central mountain ridge of Israel enable us to examine the nature of the rain shadow aridity during glacial and interglacial intervals. Speleothem growth occurred during marine glacial isotopic periods, with no growth during the two last marine isotope interglacial intervals and during the peak of the Last Glacial Maximum. This contrasts with speleothem growth in caves located on the western flank of the central mountain ridge, in the Eastern Mediterranean semiarid climatic zone, which continued throughout the last 240,000 yr. Thus, during glacial periods water reached both sides of the central mountain ridge. A comparison of the present-day rain and cave water isotopic compositions and amounts at the Ma’ale Efrayim Cave site with those on the western flank shows that evaporation and higher temperatures on the eastern flank are major influences on isotopic composition and the lack of rainfall. The δ18O and δ13C profiles of the speleothems deposited between 67,000 and 25,000 yr B.P. match the general trends of the isotopic profiles of Soreq Cave speleothems, suggesting a similar source (eastern Mediterranean Sea) and similar climatic conditions. Thus, during glacial periods the desert boundary effectively migrated further south or east from its present-day location on the eastern flank, whereas interglacial periods appear to have been similar to the present, with the desert boundary at the same position. The decrease in overall temperature and a consequent reduction in the evaporation to precipitation ratios on the eastern flank are viewed as the major factors controlling the decay of the rain shadow effect during glacial periods.
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Heidke, Inken, Denis Scholz, and Thorsten Hoffmann. "Lignin oxidation products as a potential proxy for vegetation and environmental changes in speleothems and cave drip water – a first record from the Herbstlabyrinth, central Germany." Climate of the Past 15, no. 3 (June 14, 2019): 1025–37. http://dx.doi.org/10.5194/cp-15-1025-2019.
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Abstract. Here, we present the first quantitative speleothem record of lignin oxidation products (LOPs), which has been determined in a Holocene stalagmite from the Herbstlabyrinth Cave in central Germany. In addition, we present LOP results from 16 months of drip water monitoring. Lignin is only produced by vascular plants and therefore has the potential to be an unambiguous vegetation proxy and to complement other vegetation and climate proxies in speleothems. We compare our results with stable isotope and trace element data from the same sample. In the stalagmite, LOP concentrations show a similar behavior to P, Ba and U concentrations, which have previously been interpreted as vegetation proxies. The LOP S∕V and C∕V ratios, which are usually used to differentiate between angiosperm and gymnosperm and woody and non-woody vegetation, show complex patterns suggesting additional influencing factors, such as transport and microbiological effects. The drip water from a fast drip site shows a seasonal pattern of LOPs with low LOP concentrations in winter and higher LOP concentrations in summer. These results indicate the potential of LOPs as a new proxy for vegetational and environmental changes in speleothems but also demonstrate the complexity and the current limitations of our understanding of the transport of lignin from the soil into the cave and the speleothems.
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Onac, B. P., W. B. White, and I. Viehmann. "Leonite [K2Mg(SO4)2·4H2O], konyaite [Na2Mg(SO4)2·5H2O] and syngenite [K2Ca(SO4)2·H2O] fromTausoare Cave, Rodnei Mts, Romania." Mineralogical Magazine 65, no. 1 (February 2001): 103–9. http://dx.doi.org/10.1180/002646101550154.
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AbstractTausoare Cave is renowned in Romania for its gypsum and mirabilite speleothems. Of interest are the white crystalline speleothems formed on the floor of the ‘Sala de Mese’ (Dining Room) that were previously described as consisting of mirabilite. The samples we collected reveal crystals of two different habits. One shows the characteristic mirabilite fibrous crystals (cotton-like speleothem) while the other formed bladed and short prismatic crystals which comprise the delicate ‘cave flowers’. The mineral association was characterized by means of X-ray analysis, scanning electron microscopy and electron microprobe. Beside thenardite (dehydration product of mirabilite) we also identified three sulphate minerals: leonite [K2Mg(SO4)2·4H2O], syngenite [K2Ca(SO4)2·H2O] and konyaite [Na2Mg(SO4)2·5H2O]. Of these, leonite and konyaite have never been reported in a cave environment. This paper describes the mineralogy of this particular sulphate deposit and offers some viewpoints on the crystallogenesis.
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Pawlak, Jacek. "The speleothem oxygen record as a proxy for thermal or moisture changes: a case study of multiproxy records from MIS 5–MIS 6 speleothems from the Demänová Cave system." Climate of the Past 17, no. 3 (May 18, 2021): 1051–64. http://dx.doi.org/10.5194/cp-17-1051-2021.
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Abstract. Speleothems are an important source of palaeoclimatic information about the terrestrial environment. The basic advantages of speleothems are their high preservation potential, the possibility of precise dating using the uranium-series (U-series) method, and many different proxies, such as stable isotopes, trace elements, and microfabrics, which can be interpreted in terms of palaeoclimatic conditions. Currently, central Europe is located in a transitional climate zone under the influence of both oceanic and continental climates. However, in the past, the region could have been under a stronger continental climate influence during cold glacial episodes or a stronger oceanic climate influence during wetter interglacial episodes. Long-term speleothem records can add new beneficial data about past climate changes in the region. The multiproxy record of the JS9 stalagmite, collected in the Demänová Cave system (Slovakia), represents a ca. 60 kyr period (143–83 ka). A multiproxy interpretation of the JS9 record shows that long-term δ18O trends can be interpreted as global/regional temperature changes, whereas short-term δ18O signals reflect changes in humidity. In contrast to the records from the Alps and the northern Tatra Mountains, the δ18O record of speleothem JS9 shows instantaneous decreasing episodes during Termination II. This indicates that the Carpathian Belt was an important climatic barrier at that time.
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Gordon, David, Peter L. Smart, D. C. Ford, J. N. Andrews, T. C. Atkinson, P. J. Rowe, and N. S. J. Christopher. "Dating of Late Pleistocene Interglacial and Interstadial Periods in the United Kingdom from Speleothem Growth Frequency." Quaternary Research 31, no. 1 (January 1989): 14–26. http://dx.doi.org/10.1016/0033-5894(89)90082-3.
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AbstractThe growth of speleothems is indicative of interglacial and interstadial conditions in the United Kingdom, since their growth is dependent on two factors. First, the occurrence of significant diffuse groundwater recharge and, second, the biogenic production of carbon dioxide in the soil, both are dependent on temperature and water availability. The growth frequency of speleothems is examined using a cumulative distributed error frequency method applied to 341 uncontaminated uranium-series age determinations. The curves derived are shown to be statistically stable, and the ages of the peaks are interpreted as the best estimates of the ages of interglacial and interstadial periods. Ten such periods are recognized during the interval 220,000 to 20,000 yr B.P., considerably more than are currently recognized in the UK pollen- and coleoptera-based Quaternary stratigraphy. Correlations between the speleothem growth frequency peaks and last interglacial (Ipswichian) sites can be made, but correlations with last glacial (Devensian) interstadial sites are limited because of the paucity of dates. The speleothem growth frequency record provides a well-dated terrestrial chronology for the past 140,000 yr B.P., which directly reflects regional palaeoclimatic conditions in Britain, and should prove very useful in unravelling the complex stratigraphy of the Devensian and Ipswichian stages.
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Hellstrom, John, Malcolm McCulloch, and John Stone. "A Detailed 31,000-Year Record of Climate and Vegetation Change, from the Isotope Geochemistry of Two New Zealand Speleothems." Quaternary Research 50, no. 2 (September 1998): 167–78. http://dx.doi.org/10.1006/qres.1998.1991.
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Uranium-series dating and stable isotope analyses of two speleothems from northwest Nelson, New Zealand, record changes in regional climate and local forest extent over the past 31,000 years. Oxygen isotope variation in these speleothems primarily represents changes in the meteoric waters falling above the caves, possibly responding to latitudinal changes in the position of the Subtropical Front in the Tasman Sea. Seven positive excursions can be identified in the oxygen isotope record, which coincide with periods of glacier advance, known to be sensitive to northward movement of the Subtropical Front. Four glacier advances occurred during oxygen isotope stage 2, with the most extreme glacial conditions centered on 19,000 cal yr B.P. An excursion in the oxygen isotope record from 13,800 to 11,700 cal yr B.P. provides support for a previously identified New Zealand glacier advance at the time of the Younger Dryas Stade, but suggests it began slightly before the Younger Dryas as recorded in Greenland ice cores. Carbon isotope variations in the speleothems record changes in forest productivity, closely matching existing paleovegetation records. On the basis of vegetation changes, stage 2 glacial climate conditions terminated abruptly in central New Zealand, from 15,700 to 14,200 cal yr B.P. Evidence of continuous speleothem growth at one site suggests that depression of the local treeline was limited to 600–700 m below its present altitude, throughout the last 31,000 years.
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Engel, John, Jon Woodhead, John Hellstrom, Susan White, Nicholas White, and Helen Green. "Using speleothems to constrain late Cenozoic uplift rates in karst terranes." Geology 48, no. 8 (April 29, 2020): 755–60. http://dx.doi.org/10.1130/g47466.1.
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Abstract The utility of speleothems as environmental and geological archives has greatly expanded with recent advances in geochronology. Here we reevaluate their ability to constrain late Cenozoic uplift in karst terranes. Using combined U-Th and U-Pb speleothem chronologies for the Buchan karst along the passive margin of southeastern Australia, we calculate a maximum uplift rate of 76 ± 7 m m.y.−1 maintained over the past 3.5 m.y. The timing and extent of this process is consistent with independent constraints on Neogene uplift in Australia, possibly in response to increased plate-boundary strain with New Zealand. Speleothem chronologies provide highly precise age control on individual events and the potential for near-continuous records across long periods of geological time, complementing and expanding upon existing uplift proxies.
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Dub, S., G. Mizens, V. Kuleshov, and O. Petrov. "Geochemical and isotopic characteristics of paleocavities mineral filling in the Upper Devonian-Lower Carboniferous limestones on the eastern slope of the Middle Urals (vicinity of Pershino village)." Vestnik of geosciences, no. 7 (September 8, 2022): 32–44. http://dx.doi.org/10.19110/geov.2022.7.4.
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Lithology and geochemistry of carbonate filling in ancient karst cavities in the Famennian-Tournaisian limestone sequence of the Rezh subzone at the eastern slope of the Middle Urals are considered. Mineral filling of paleocavities differs from typical modern subaerial speleothems. Caves are mainly filled with white massive coarse-grained calcite (cave spar), red-colored argillaceous-carbonate microgranular deposits (carbonates with an admixture of terra rossa, cave laminites) and collapse breccias, composed of host limestones fragments. The rare earth elements (REE) patterns and the isotopic composition of carbon indicate a very weak effect (or its absence) of soil or meteoric waters on the carbonate system: the speleothem calcite inherited these characteristics from the host limestones. At the same time, the isotopic composition of oxygen indicates the primary meteoric genesis of solutions and/or relatively high temperatures of calcite crystallization. Most likely, the studied speleothems were formed from solutions of surface origin circulating in the sedimentary strata for a long time (hypogene sediments).
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Frisia, S., A. Borsato, R. N. Drysdale, B. Paul, A. Greig, and M. Cotte. "A re-evaluation of the palaeoclimatic significance of phosphorus variability in speleothems revealed by high-resolution synchrotron micro XRF mapping." Climate of the Past Discussions 8, no. 4 (July 11, 2012): 2557–82. http://dx.doi.org/10.5194/cpd-8-2557-2012.
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Abstract. The distribution of phosphorous (P) in one modern and two Early Pliocene speleothems formed in low-lying, Christmas Island and the coastal Nullarbor caves wet settings in Australia is here investigated by microscopy and ultra-high resolution chemical mapping. Monitoring data in the modern setting suggest that co-precipitation of P with calcite occurs when the drip rate decreases, the aquifer is progressively drained and microbial mats possibly aid in the formation of concentrating phosphates. A bulk partition coefficient is proposed, which indicates that the P enrichment in the speleothem could be accounted for by inorganic processes. Our interpretation of the hydrological significance of P incorporation in wet, tropical speleothems is then used to interpret P peaks associated with micritic and stromatolithic layers in the two Early Pliocene stalagmites from the Nullarbor. From these observations it is speculated that dry periods may have interrupted the wet climate regime at ca. 4 Myr ago, hinting at a possible early onset of the Pleistocene climate mode.
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Feinberg, Joshua M., and Kathryn K. Hobart. "Attraction in the Dark: The Magnetism of Speleothems." Elements 17, no. 2 (April 1, 2021): 113–18. http://dx.doi.org/10.2138/gselements.17.2.113.
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No matter how quiet and pristine a cave setting may appear, all speleothems contain assemblages of magnetic minerals. These iron oxide minerals are derived largely from overlying soils, though minor fractions may come from the residuum of dissolved bedrock, reworked sediment carried by episodic floods, geomicrobiological activity, and even windblown dust. Regardless of their origin, these minerals become aligned with Earth’s ambient magnetic field before they are fixed within a speleothem’s growing carbonate matrix. Here, we describe how the magnetism of stalagmites and flowstone can be used to chronicle high-resolution geomagnetic behavior and environmental change.
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Spear, John R., Hazel A. Barton, Charles E. Robertson, Christopher A. Francis, and Norman R. Pace. "Microbial Community Biofabrics in a Geothermal Mine Adit." Applied and Environmental Microbiology 73, no. 19 (August 10, 2007): 6172–80. http://dx.doi.org/10.1128/aem.00393-07.
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ABSTRACT Speleothems such as stalactites and stalagmites are usually considered to be mineralogical in composition and origin; however, microorganisms have been implicated in the development of some speleothems. We have identified and characterized the biological and mineralogical composition of mat-like biofabrics in two novel kinds of speleothems from a 50°C geothermal mine adit near Glenwood Springs, CO. One type of structure consists of 2- to 3-cm-long, 3- to 4-mm-wide, leather-like, hollow, soda straw stalactites. Light and electron microscopy indicated that the stalactites are composed of a mineralized biofabric with several cell morphotypes in a laminated form, with gypsum and sulfur as the dominant mineral components. A small-subunit rRNA gene phylogenetic community analysis along the stalactite length yielded a diverse gradient of organisms, with a relatively simple suite of main constituents: Thermus spp., crenarchaeotes, Chloroflexi, and Gammaproteobacteria. PCR analysis also detected putative crenarchaeal ammonia monooxygenase subunit A (amoA) genes in this community, the majority related to sequences from other geothermal systems. The second type of speleothem, dumpling-like rafts floating on a 50°C pool on the floor of the adit, showed a mat-like fabric of evidently living organisms on the outside of the dumpling, with a multimineral, amorphous, gypsum-based internal composition. These two novel types of biofabrics are examples of the complex roles that microbes can play in mineralization, weathering, and deposition processes in karst environments.
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Sanjurjo-Sanchez, Jorge, Carlos Arce Chamorro, Juan Vidal Romaní, Marcos Vaqueiro-Rodríguez, Victor Barrientos, and Joeri Kaal. "On the genesis of aluminum-rich speleothems in a granite cave of NW Spain." International Journal of Speleology 50, no. 1 (January 2021): 25–40. http://dx.doi.org/10.5038/1827-806x.50.1.2358.
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Granite massifs often contain caves, with dimensions ranging from a few meters up to 1,000 m, also referred to as pseudokarst. The speleothems in such caves are mostly composed of either Si-rich (commonly opal-A) or Al-rich authigenic mineraloids. Whereas the formation and geochemical composition of opal-A biospeleothems have been studied and are fairly well understood, knowledge on the Al-rich analogues is scarce. This work reports for the first time a study on the composition, accretion process, age and growth rate of an Al-rich speleothem type flowstone from the A Trapa Cave System (Galicia, NW Spain), developed in a granite cave. To understand the growth process, trickling water was analyzed and the deposition environment inside the cave was characterized. We found that the speleothems are alternating Si- and Al-rich layered deposits formed between 1,635 ± 75 and 1,243 ± 58 cal BP by percolating water that carries underground mineral grains, dissolved ions, and organic matter from soil and the weathered bedrock above the cave.
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TÎRLĂ, Laura, Virgil DRĂGUȘIN, Ionuț MIREA, and Teodor COJOCARIU. "Speleomorphology of M3-R2 – The highest cave in the SE Carpathians." Revista de Geomorfologie 18, no. 1 (October 22, 2016): 59–68. http://dx.doi.org/10.21094/rg.2016.103.
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High-alpine caves are currently in the spotlight of research as they are host to speleothems, key recorders of Quaternary environmental change. Based on modern survey and analytical techniques, we investigated the karst morphology of M3-R2 Cave, the highest alpine cave in the Romanian Carpathians. Spatial modeling in Compass has shown survey details and cave morphology. We recalculated the main cave parameters (development/extension/depth), obtaining 47 m/21 m/-18.15 m, respectively. Slope ranges between 25° and 45°, with short passage segments of 5° to 10°. The cave developed at the intersection of a SW-dipping schistosity plan with two fracture sets, occurred under compression conditions. It is a remnant of a once longer cave system, which was progressively eroded under glacial conditions. Speleothem diversity is uncommonly rich for a marble cave, with dominant moonmilk formations, stalagmites and draperies. Due to its location/elevation, evolution and speleothems, this cave has a great potential in providing important paleoclimatic information compared to other karst landforms in South Carpathians.
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Lauritzen, Stein-Erik. "High-Resolution Paleotemperature Proxy Record for the Last Interglaciation Based on Norwegian Speleothems." Quaternary Research 43, no. 2 (March 1995): 133–46. http://dx.doi.org/10.1006/qres.1995.1015.
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AbstractTwo speleothems from a coastal lowland and an alpine cave site in northern Norway grew in isotopic equilibrium during Termination II and marine isotope stage 5 (150,000-80,000 yr B.P.), as dated by the U-series technique. The stable isotope record (δ18O, δ13C) displays a time resolution down to ∼20 yr. The δ18Oc signal in the two speleothems appears to be mainly dominated by the meteoric signal; i.e., there is a positive relationship between δ18Oc and temperature [∂(δ18Oc/∂T > 0]. The FM-2 couplet, a Younger Dryas type two-step structure in Termination II at 132,000 ± 5000 and 129,000 ± 5000 yr is prominent in the speleothem record. The record correlates well with details and gross features of the GRIP ice core and confirms the time scale and the unstable climate proposed for substage 5e. The isotopic response in Termination II is delayed relative to the Devil's Hole record and is in accord with the SPECMAP chronology, but cooling at the end of substage 5e seems to be synchronous between Devil's Hole and the Norwegian flowstones.
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Antonioli, Fabrizio, Stefano Furlani, Paolo Montagna, and Paolo Stocchi. "The Use of Submerged Speleothems for Sea Level Studies in the Mediterranean Sea: A New Perspective Using Glacial Isostatic Adjustment (GIA)." Geosciences 11, no. 2 (February 9, 2021): 77. http://dx.doi.org/10.3390/geosciences11020077.
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The investigation of submerged speleothems for sea level studies has made significant contributions to the understanding of the global and regional sea level variations during the Middle and Late Quaternary. This has especially been the case for the Mediterranean Sea, where more than 300 submerged speleothems sampled in 32 caves have been analysed so far. Here, we present a comprehensive review of the results obtained from the study of submerged speleothems since 1978. The studied speleothems cover the last 1.4 Myr and are mainly focused on Marine Isotope Stages (MIS) 1, 2, 3, 5.1, 5.3, 5.5, 7.1, 7.2, 7.3, and 7.5. The results reveal that submerged speleothems represent extraordinary archives providing accurate information on former sea level changes. New results from a stalagmite collected at Palinuro (Campania, Italy) and characterized by marine overgrowth are also reported. The measured elevations of speleothems are affected by the local response to glacial and hydro-isostatic adjustment (GIA), and thus might significantly deviate from the global eustatic signal. A comparison of the ages and altitude values of the Mediterranean speleothems and flowstone from the Bahamas with local GIA provides a new scenario for MIS 5 and 7 sea level reconstructions.
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Johnston, V. E., A. Borsato, C. Spötl, S. Frisia, and R. Miorandi. "Monitoring stable isotopes in caves over altitudinal gradients: fractionation behaviour and inferences for speleothem sensitivity to climate change." Climate of the Past Discussions 8, no. 4 (August 14, 2012): 3613–55. http://dx.doi.org/10.5194/cpd-8-3613-2012.
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Abstract. Large changes of the climate can dramatically affect the environment surrounding and within a cave. This variability, including temperature shifts, can change the amount of in-cave isotopic fractionation affecting speleothems, potentially leaving these records difficult to interpret. Here, caves located in steep altitudinal topography in the Northern Italian Alps are used to create a thermal gradient (3–12 °C) to study the effects of temperature on the speleothem isotope record. The data indicate that the amount of in-cave oxygen isotope fractionation is reduced to minimum values of around 0.25‰ with cooler temperatures and under faster dripping stalactites, which infers that such sites would be most suitable for palaeoclimate reconstruction. However, when considering the possible freezing periods, reduced saturation index and fluctuating drip rates, such sites appear less than ideal for study on long timescales. The importance of picking the best site(s) within a cave for palaeoclimate reconstruction is paramount, to reduce the in-cave fractionation and gain a record that reflects climate changes. A method for rapid determination of calcite fractionation is demonstrated here, through prior cave monitoring of dripwaters and calcite precipitates, permitting an informed choice of speleothems for further study.
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Horvatinčić, Nada, Romana Čalić, and Mebus A. Geyh. "Interglacial Growth of Tufa in Croatia." Quaternary Research 53, no. 2 (March 2000): 185–95. http://dx.doi.org/10.1006/qres.1999.2094.
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AbstractTufa samples from the Krka River area in Croatia were dated by 14C and 230Th/234U methods. The study area is situated in the karst region of the southern Dinarides. 14C ages of 40 tufa samples collected at the waterfalls coincide with the early Holocene interglaciation, up to 6000 14C yr B.P. Comparison of conventional 14C dates of Holocene tufa and those of speleothems in the Dinaric Karst shows that speleothem formation started several thousand years earlier than tufa growth. Samples of old tufa deposits from the Krka River (17) and Plitvice Lakes (12) area and speleothem samples from caves in Dinaric Karst (5) yield 34 230Th/234U dates, most of which cluster around interglacial marine δ18O stage 5 (21). Eight of 13 older dates belong to interglacial stages 7 and 9; only 5 dates fall within stage 6 and 8 glaciations. 230Th/234U dates of speleothems and tufa samples from central Europe have indicated that these were formed preferentially during warm and humid interglacial and interstadial periods, and it appears that this is true of southern Croatia as well. Stable isotope (δ13C, δ18O) analyses of 40 tufa samples from the Krka River area were compared with stable isotope analyses of tufa from the Plitvice Lakes area. The δ13C values for both locations are similar and range from −10 to −6‰, indicating similar conditions of tufa formation. A systematic difference between the δ18O values of tufa in these two areas reflects the regional distribution of the oxygen composition of precipitation.
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Fairchild, Ian J., M. Bar-Matthews, PM Wynn, and IJ Orland. "Seasonality in speleothems." Past Global Changes Magazine 22, no. 1 (April 2014): 24–25. http://dx.doi.org/10.22498/pages.22.1.24.
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Spötl, Christoph, and Augusto Mangini. "Speleothems and paleoglaciers." Earth and Planetary Science Letters 254, no. 3-4 (February 2007): 323–31. http://dx.doi.org/10.1016/j.epsl.2006.11.041.
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Vieten, Rolf, and Francisco Hernandez. "StalGrowth—A Program to Estimate Speleothem Growth Rates and Seasonal Growth Variations." Geosciences 11, no. 5 (April 27, 2021): 187. http://dx.doi.org/10.3390/geosciences11050187.
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Speleothems are one of the few archives which allow us to reconstruct the terrestrial paleoclimate and help us to understand the important climate dynamics in inhabited regions of our planet. Their time of growth can be precisely dated by radiometric techniques, but unfortunately seasonal radiometric dating resolution is so far not feasible. Numerous cave environmental monitoring studies show evidence for significant seasonal variations in parameters influencing carbonate deposition (calcium-ion concentration, cave air pCO2, drip rate and temperature). Variations in speleothem deposition rates need to be known in order to correctly decipher the climate signal stored in the speleothem archive. StalGrowth is the first software to quantify growth rates based on cave monitoring results, detect growth seasonality and estimate the seasonal growth bias. It quickly plots the predicted speleothem growth rate together with the influencing cave environmental parameters to identify which parameter(s) cause changes in speleothem growth rate, and it can also identify periods of no growth. This new program has been applied to multiannual cave monitoring studies in Austria, Gibraltar, Puerto Rico and Texas, and it has identified two cases of seasonal varying speleothem growth.
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Cadorin, J. F., D. Jongmans, A. Plumier, T. Camelbeeck, S. Delaby, and Y. Quinif. "Modelling of speleothems failure in the Hotton cave (Belgium). Is the failure earthquake induced?" Netherlands Journal of Geosciences 80, no. 3-4 (December 2001): 315–21. http://dx.doi.org/10.1017/s001677460002391x.
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AbstractTo provide quantitative information on the ground acceleration necessary to break speleothems, laboratory measurements on samples of stalagmite have been performed to study their failure in bending. Due to their high natural frequencies, speleothems can be considered as rigid bodies to seismic strong ground motion. Using this simple hypothesis and the determined mechanical properties (a minimum value of 0.4 MPa for the tensile failure stress has been considered), modelling indicates that horizontal acceleration ranging from 0.3 m/s2 to 100 m/s2 (0.03 to 10g) are necessary to break 35 broken speleothems of the Hotton cave for which the geometrical parameters have been determined. Thus, at the present time, a strong discrepancy exists between the peak accelerations observed during earthquakes and most of the calculated values necessary to break speleothems. One of the future research efforts will be to understand the reasons of the defined behaviour. It appears fundamental to perform measurements on in situ speleothems.
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Fleitmann, Dominik, Stephen J. Burns, Ulrich Neff, Augusto Mangini, and Albert Matter. "Changing moisture sources over the last 330,000 years in Northern Oman from fluid-inclusion evidence in speleothems." Quaternary Research 60, no. 2 (September 2003): 223–32. http://dx.doi.org/10.1016/s0033-5894(03)00086-3.
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AbstractSpeleothems from Hoti Cave in northern Oman provide a record of continental pluvial periods over the last 330,000 yr. Periods of rapid speleothem deposition occurred from 6000 to 10,500, 78,000 to 82,000, 120,000 to 135,000, 180,000 to 200,000, and 300,000 to 330,000 yr ago, with little or no growth during the intervening periods. During each of these five pluvial periods, δD values of water extracted from speleothem fluid inclusions (δDFI) are between −60 and −20‰ (VSMOW) and δ18O values of speleothem calcite (δ18OC) are between −12 and −4‰ to (VPDB). These values are much more negative than modern rainfall (for δD) or modern stalagmites (for δ18O). Previous work on the isotopic composition of rainfall in Oman has shown that northern and southern moisture sources are isotopically distinct. Combined measurements of the δD values of fluid-inclusion water with calculated δ18O values from peak interglacial speleothems indicate that groundwater was predominantly recharged by the southern (Indian Ocean) moisture source, when the monsoon rainfall belt moved northward and reached Northern Oman during each of these periods.
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Surić, Maša, Petra Bajo, Robert Lončarić, Nina Lončar, Russell N. Drysdale, John C. Hellstrom, and Quan Hua. "Speleothem Records of the Hydroclimate Variability throughout the Last Glacial Cycle from Manita peć Cave (Velebit Mountain, Croatia)." Geosciences 11, no. 8 (August 19, 2021): 347. http://dx.doi.org/10.3390/geosciences11080347.
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We present stable carbon (δ13C) and oxygen (δ18O) isotope records from two partially coeval speleothems from Manita peć Cave, Croatia. The cave is located close to the Adriatic coast (3.7 km) at an elevation of 570 m a.s.l. The site experienced competing Mediterranean and continental climate influences throughout the last glacial cycle and was situated close to the ice limit during the glacial phases. U-Th dating constrains the growth history from Marine Isotope Stage (MIS) 5 to MIS 3 and the transition from MIS 2 to MIS 1. 14C dating was used to estimate the age of the youngest part of one stalagmite found to be rich in detrital thorium and thus undatable by U-Th. On a millennial scale, δ18O variations partly mimic the Dansgaard–Oeschger interstadials recorded in Greenland ice cores (Greenland Interstadials, GI) from GI 22 to GI 13. We interpret our δ18O record as a proxy for variations in precipitation amount and/or moisture sources, and the δ13C record is interpreted as a proxy for changes in soil bioproductivity. The latter indicates a generally reduced vegetation cover towards MIS 3–MIS 4, with shifts of ~8‰ and approaching values close to those of the host rock. However, even during the coldest phases, when a periglacial setting and enhanced aridity sustained long-residence-time groundwater, carbonic-acid dissolution remains the driving force of the karstification processes. Speleothem morphology follows changes in environmental conditions and complements regional results of submerged speleothems findings. Specifically, narrow sections of light porous spelaean calcite precipitated during the glacial/stadial sea-level lowstands, while the warmer and wetter conditions were marked with compact calcite and hiatuses in submerged speleothems due to sea-level highstands. Presumably, the transformation of this littoral site to a continental one with somewhat higher amounts of orographic precipitation was a site-specific effect that masked regional environmental changes.
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Honiat, Charlotte, Gabriella Koltai, Yuri Dublyansky, R. Lawrence Edwards, Haiwei Zhang, Hai Cheng, and Christoph Spötl. "A paleoprecipitation and paleotemperature reconstruction of the Last Interglacial in the southeastern Alps." Climate of the Past 19, no. 6 (June 15, 2023): 1177–99. http://dx.doi.org/10.5194/cp-19-1177-2023.
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Abstract. The Last Interglacial (LIG, ∼130–116 ka) was one of the warmest interglacials of the past 800 000 years and an important test bed for future climate conditions warmer than today. LIG temperature reconstructions from marine records and paleoclimate models show that middle and high northern latitudes were considerably warmer (by about 2 to 5 ∘C) compared to today. In central Europe, the LIG has been widely studied using pollen and more recently chironomids preserved in lake sediments. While these bio-archives document temperature changes across the LIG, they are commonly poorly constrained chronologically. Speleothems and fluid inclusions contained therein offer superior age control and provide information on past climate, including qualitative and partly also quantitative records of temperature and precipitation. Here, we present a precisely dated fluid-inclusion record based on seven speleothems from two caves in the southeastern Alps (Obir and Katerloch) and use a δ2H/T transfer function to reconstruct regional LIG temperatures. We report a temperature change across the glacial–interglacial transition of 5.2±3.1 ∘C and peak temperatures at ∼127 ka of 2.4±2.8 ∘C above today's mean (1973–2002). The fluid-inclusion δ2H record of these speleothems exhibits millennial-scale events during the LIG that are not well expressed in the δ18Ocalcite. The early LIG in the southeastern Alps was marked by an important climate instability followed by progressively more stable conditions. Our record suggests that the southeastern Alps predominantly received Atlantic-derived moisture during the early and middle LIG, while more Mediterranean moisture reached the study site at the end of the LIG, buffering the speleothem δ18Ocalcite signal. The return towards colder conditions is marked by an increase in δ13C starting at ∼118 ka, indicating a decline in the vegetation and soil activity.
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Jones, Brian, and Duncan S. Smith. "Open and filled karst features on the Cayman Islands: implications for the recognition of paleokarst." Canadian Journal of Earth Sciences 25, no. 8 (August 1, 1988): 1277–91. http://dx.doi.org/10.1139/e88-123.
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The dolostones of the Oligocene–Miocene Bluff Formation on the Cayman Islands are characterized by well-developed surficial, interface, and subsurface karst features that are open or filled with speleothems and sediment.Some of the open caves show evidence of a minimum of two stages of development related to dissolution in the phreatic zone and the vadose zone. The development of speleothemic formations (e.g., stalactites, stalagmites, columns) is limited in some caves but extensive in others. Some of the caves have limited amounts of sediment on their floors. In these caves, the speleothems and sediments are still formed of CaCO3 and thus contrast sharply with the dolostone of the Bluff Formation in which they occur. Some of the joints, sinkholes, and caves are filled with breccia, caymanite, terra rossa, terra rossa breccia, pisolitic limestone, and speleothems. Although filled, such karst features are analogous to the open karst features that occur elsewhere on the islands. The filling of joints, sinkholes, or caves is not directly related to the age of the karst development, since caves of the same age may be open or filled. This suggests that local conditions, such as the availability of sediment or the nature of the waters flowing through the caves, played an important role in determining whether a karst feature is filled.Surficial karst features have a low preservation potential, whereas interface and subsurface karst features have a high preservation potential in some circumstances. In the case of sinkholes this assumes that later transgressions did not remove the upper part of the rock body that contained the filled sinkholes. For caves this assumes that they were filled with speleothems and sediment prior to their reaching such a size that collapse of the overlying strata occurred because of the lack of support. If collapse occurs, the presence of caves can only be inferred from the resultant collapse breccias. A potentially valuable criterion for the recognition of paleokarst may lie in the fact that the rocks filling open karst features (e.g., joints, sinkholes, caves) may contrast sharply with the host strata in terms of both lithology and age.