Paleoclimate implications of mass spectrometric dating of a British flowstone, 1995, Baker A, Smart Pl, Edwards Rl,

The timing of growth phases in a cave flowstone from Yorkshire, England, has been precisely dated by thermal ionization mass spectrometric 238 U- 234 U- 230 Th dating. Six growth periods of both short duration and fast growth rate are separated by nondepositional hiatuses. The ages of these phases were determined to be 128.8 or -2.7, 103.1 or -1.8, 84.7 or -1.2, 57.9 or -1.5, 49.6 or -1.3, and 36.9 or -0.8 ka. There is a remarkably good correlation between the periods of active speleothem growth and the timing of solar insolation maxima, derived from orbital parameters, which has not previously been reported. Speleothem growth theory and evidence from other terrestrial paleoclimate records suggest that episodic, rapid growth phases at the insolation maxima are most likely to be caused by changes in either precipitation intensity or volume, which caused switching in the routing of water flow in the unsaturated zone above the cave. Such a result provides new evidence of the importance of variations in solar insolation for terrestrial paleoclimate and offers the potential for derivation of a paleowetness index from speleothem growth

Seismotectonic versus man-induced morphological changes in a cave on the Arrabida chain (Portugal), 1999, Crispim Ja,

Distinctions between cave morphologies originating from seismic or active tectonics and those generated by natural elastic breakdown or by human activity must be made using unambiguous interpretative criteria. Easily accessible caves in particular, which may have been visited for centuries or millennia, or caves located near engineering works or quarries using great quantities of explosives, may have broken speleothems, breakdowns or detachment joints unrelated to seismic events or tectonic movements. Zambujal cave lies near neotectonic and seismic structures associated with a Plio-Quaternary 200 m uplift of the Arrabida chain and has suffered impacts resulting from quarrying, followed by possible vandalism. It is thus an example for which it is difficult to decipher morphological agents as there is the possibility that identical forms have been generated by several causes, which may have repeated at different episodes of its evolution. However, a careful morphological interpretation makes it possible to accept the existence of two seismic episodes, an 'ancient' one and a 'modern' one. The detection of other episodes between these is only possible using absolute dating. (C) Elsevier, Paris

Le karst des plateaux jurassiques de la moyenne valee de l'Ardeche; datation par paleomagnetisme des phases d'evolution plio-quaternaires (aven de la Combe Rajeau), 2001, Audra P, Camus H, Rochette P,

Thanks to its immunity, karst is an excellent recorder of environmental change, which also offers the possibility for dating. Karst records position of old base levels, in particular to which were linked horizontal underground drains located near the piezometric surface. After a base level lowering, a new drain appears at a lower level, the old perched drain being abandoned. If base level lowering is slow, the initial drain is progressively entrenched, forming a canyon. The 'Combe Rajeau' cave system corresponds to this last type: a 100 m high underground canyon, continuously entrenched during the Ardeche valley downcutting. The underground river left several terraces during the entrenchment. Knowing that speleothem U/Th radiometric dating method covers only the most recent part of karst systems history, which spans over several million years, paleomagnetism has been applied to date the Combe Rajeau sediments. A more precise knowledge of the evolution phases of this system provides a better understanding of the middle Ardeche valley evolution upon which it depends

Cave Genesis and its relationship to surface processes: investigations in the Siebenhengste region (BE, Switzerland), PhD Thesis, 2002, Haeuselmann, Ph.

This PhD thesis deals with the speleogenesis of the youngest six phases in the Siebenhengste system (Switzerland). A speleogenetic model is developed, linking the four-state-model with the model of Audra (1994), taking into account the speleogenetic processes in the flooding zone. The refinement of the speleogenetic phases allowed to reconstruct the valley deepening processes in the late Quarternary. Moreover, an idea about the landscape evolution since the Mio-Pliocene is sketched. U/Th datings allowed the timing of the last four speleogenetic phases as well as glacial advances and retreats during the last 400'000 years, thus considerably enhancing the continental Quarternary record. With information from Baerenschacht and St. Beatus Cave, the tectonic history and the geometry of the folds could be retraced. A comprehensive analysis of all dye tracing experiments is given. 

Dosimetric and radiocarbon chronology of a pre-Wisconsinan mastodon fossil locality at East Milford, Nova Scotia, Canada, 2003, Godfreysmith D. I. , Grist A. M. , Stea R. R. ,

We report the final results of a multidisciplinary geochronological study of two subfossil mastodon remains and the sediments associated with them. from the East Milford, N.S. mastodon locality discovered in 1991. The mastodons, which were found in a karstic sinkhole system, are the latest and the most complete of several mastodon remains discovered in Nova Scotia, New Brunswick and Maine over the last 170 years. The unconsolidated sediments containing the adult specimen were dated using optical dating (IRSL); the mastodon dental enamel was dated using electron spin resonance (ESR); and bone collagen from both individuals plus associated wood were dated using radiocarbon (C-14) dating. Two samples of sediment adhering to the walls of the karstic cavity at the elevation corresponding to the location of the adult specimen yielded statistically indistinguishable IRSL ages of 127 13 (EMM1) and 143 16 ka (EMM2), with a weighted mean of 133 6 ka. This is consistent with pollen data which indicate an interglacial climate. On the basis of its stratigraphic position with respect to overlying till units, the locality is attributed to oxygen isotope stage 5. Three ESR dates on dental enamel (natural prompt, deproteinated prompt, and deproteinated delayed) yielded statistically indistinguishable ages whose weighted mean is 74.9 5.0 ka. This indicates consignment to the geologic record of the mastodon tooth during terminal oxygen isotope stage 5a, when the climatic cooling leading to the Wisconsinan glacial period had already begun. Fission-track analysis of the enamel and dentine cross sections showed minimal U uptake, resulting in no need for early, linear, or late uptake modelling. The direct ESR age indicates that the specimen either became mired in a cavity that was already at least partly infilled with older, probably waterlogged, sediments, or that the sediment's IRSL signal was not completely erased during deposition. The dosimetric ages are consistent with limiting radiocarbon ages on bone collagen (juvenile > 45,760 years BP; adult greater than or equal to 37,040 1730 BP) and wood (near the adult mastodon > 51,000 BP; organic-rich horizon above the karst surface > 50,000 BP). These results provide the first direct age on a mastodon fossil from Atlantic Canada, and the first numeric estimate to demonstrate that mammoths were present in this region during pre-Wisconsinan times, specifically during late oxygen isotope stage 5a. (C) 2003 Elsevier Science Ltd. All rights reserved

Comparison of 14C and 230Th/234U dating of speleothems from submarine caves in the Adriatic Sea (Croatia), 2004, Surić, Maš, A, Jurač, Ić, Mladen, Horvatinč, Ić, Nada

Among the 16 speleothems that were collected from 7 submarine caves and pits for the purpose of 14C and U-Th dating and reconstructing sea-level changes, two speleothems were dated by both methods. Different environmental conditions during the speleothem deposition and after the submergence resulted with different appropriateness for speleothem dating by these techniques. Well preserved speleothems gave reliable results by both methods, while U-Th method showed disadvantage in the case of carbonates contaminated with detrital material, as well as in the case of carbonate from marine overgrowth that covers the speleothems. However, U-Th method using MC ICPMS technique which requires only 100-300 mg of sample per analysis (instead of ca. 30 g for 14C conventional method), offers better age resolution that is essential for speleothem dating.

Ochtiná Aragonite Cave (Slovakia): morphology, mineralogy and genesis, 2005, Bosák P. , Bella P. , Cilek V. , Ford D. C. , Hercman H. , Kadlec J. , Osborne A. , Pruner P. ,

Ochtiná Aragonite Cave is a 300 m long cryptokarstic cavity with simple linear sections linked to a geometrically irregular spongework labyrinth. The limestones, partly metasomatically altered to ankerite and siderite, occur as lenses in insoluble rocks. Oxygen-enriched meteoric water seeping along the faults caused siderite/ankerite weathering and transformation to ochres that were later removed by mechanical erosion. Corrosion was enhanced by sulphide weathering of gangue minerals and by carbon dioxide released from decomposition of siderite/ankerite. The initial phreatic speleogens, older than 780 ka, were created by dissolution in density-derived convectional cellular circulation conditions of very slow flow. Thermohaline convection cells operating in the flooded cave might also have influenced its morphology. Later vadose corrosional events have altered the original form to a large extent. Water levels have fluctuated many times during its history as the cave filled during wet periods and then slowly drained.
Mn-rich loams with Ni-bearing asbolane and birnessite were formed by microbial precipitation in the ponds remaining after the floods. Allophane was produced in the acidic environment of sulphide weathering. La-Nd-phosphate and REE enriched Mn-oxide precipitated on geochemical barriers in the asbolane layers. Ochres containing about 50 wt.% of water influence the cave microclimate and the precipitation of secondary aragonite. An oldest aragonite generation is preserved as corroded relics in ceiling niches truncated by corrosional bevels. TIMS and alpha counting U series dating has yielded ages of about 500-450 and 138-121 ka, indicating that there have been several episodes of deposition, occurring during Quaternary warm periods (Elsterian 1/2, Eemian). Spiral and acicular forms representing a second generation began to be deposited in Late Glacial (14 ka – Alleröd) times. The youngest aragonite, frostwork, continues to be deposited today. Both of the younger generations have similar isotopic compositions, indicating that they originated in conditions very similar, or identical, to those found at present in the cave.

Hypogene and supergene alteration of the Late Palaeozoic Ratburi Limestone during the Mesozoic and Cenozoic (Thailand, Surat Thani Province). Implications for the concentration of mineral commodities, 2005, Dill H. G. , Botz R. , Luppold F. W. , Henjeskunst F.

An interdisciplinary study of the Upper Carboniferous to Middle Permian Ratburi Group, Peninsular Thailand, is presented. The investigation involved sedimentary petrography, inorganic geochemistry, Sr, C, O isotope analyses, micropalaeontology as well as radio-carbon age dating. Emphasis was placed on the post-depositional evolution of the Ratburi Limestone in the Surat Thani Province. The Holocene chemical residues and the various calcite and dolomite minerals which have formed since the Late Palaeozoic in the Ratburi Limestone are the product of a complex, multistage alteration which is called supergene and hypogene karstifications, respectively. Sedimentation took place in a shelf environment with some reefs evolving during the late Murgabian at the shelf margin. There was no pre-concentration of elements, except for Ca and F during sedimentation. Diagenetic neomorphism and cementation under marine and freshwater conditions caused the Ratburi Limestone to convert into a marble-like rock. Fabric-selective dolomitization is of local scale and has impacted only on part of the Ratburi Limestone during the Lower to Upper Permian. A significant enhancement of pore space and better conduits were generated during the Late Cretaceous epithermal alteration. The most favorable conditions for the accumulation of metals were provided during the high-temperature stage of epithermal alteration when a low-metal concentration with As, Zn, Sb, U, Co and Pb existed. Unlike the other elements, Sb was subject to a multiphase concentration, giving rise to a considerable Sb deposit in the region. The most recent stage of karstification produced numerous caves, dripstones, tufa terraces and encrustations around brine pools in the study area. This alteration originated from per descensum and per ascensum processes which may be traced back to 15,000 years before present. The alteration of the Ratburi Limestone may be subdivided into two parts. The prograde post-depositional alteration, beginning with diagenesis, reached its temperature climax during epithermal subsurface alteration I. The retrograde branch of alteration lasted until the most recent times. The initial stages deposition and diagenesis took place under more or less closed-system conditions relative to the succeeding stages of the prograde alteration which saw the strongest influx of metal-bearing brine during the epithermal stage I. The retrograde branch of alteration is element-conservative.

Stalagmite evidence for the precise timing of North Atlantic cold events during the early last glacial, 2007, Drysdale Rn, Zanchetta G, Hellstrom Jc, Fallick Ae, Mcdonald J, Cartwright I,

Evidence of millennial-scale cold events following the last interglacial are well preserved in North Atlantic marine cores, Greenland ice, and pollen records from Europe. However, their timing was previously undetermined by radiometric dating. We report the first precise radiometric ages for two such events, C23 (105.1 {} 0.9 ka to 102.6 {} 0.8 ka) and C24 (112.0 {} 0.8 ka and 108.8 {} 1.0 ka), based on stable carbon and oxygen isotope measurements on a stalagmite from Italy (CC28). In addition to providing new information on the duration of these events in southern Europe, the age data provide invaluable tuning points for the Melisey I (C24) and Montaigu (C23) pollen zones identified in western Europe. The former event is of particular significance because it represents the end of the Eemian interglacial forest phase in western Europe. The new age data will also allow fine tuning of the timing and duration of Greenland stadial 24 (equivalent to C23) in the North Greenland Ice Core Project ice core and, via a common gasage chronology, tuning of the Vostok and EPICA (European Project for Ice Coring in Antarctica) ice cores

SUBMERGED SPELEOTHEMS – EXPECT THE UNEXPECTED. EXAMPLES FROM THE EASTERN ADRIATIC COAST (CROATIA), 2007, Surić, M. , Jalž, Ić, B. , Petricioli D.

With the intention of reconstructing Late Pleistocene – Holocene sea-level changes along the Eastern Adriatic coast, a series of speleothems were collected from several submerged caves and pits, in order to constrain periods of their deposition and ceased growth related to sea-level fluctuations. For that purpose, stalagmites provide more reliable records than stalactites, due to their successive layers deposited perpendicularly to the growth direction. Therefore, stalagmites have been collected preferably. But, two of 17 speleothems displayed unexpected interior morphology – speleothem L-1 collected at the depth of 1.5 m in Medvjeđa spilja Cave on Lošinj Island, and speleothem M-25 from Pit near Iški Mrtovnjak Islet collected at the depth of 25 m. Both of the samples were taken from the cave floor, in the growth position of the stalagmite. But the insight into the perpendicular cut with evident central tube revealed their true (stalactitic) origin and additional confirmations were obtained by longitudinal cut and U-Th and 14C dating. Just as the causes of their breakdowns were probably different, so were their falls; speleothem M 25 (together with several other speleothems around it) stuck in the marine sediment in its primary position, while L-1 turned upside-down and even continued crystallizing during the lower sea level. These events are possible in the continental caves, as well. Evidently, it is much easier to recognize and avoid these problems in air-filled caves than in the submarine ones where the speleothems are almost always covered with marine overgrowth, which disguises their outer morphology. Additionally, the bases of the stalagmites are also sometimes covered with marine sediment, which makes correct estimation rather difficult.

Clastic cave deposits in Botovskaya Cave (Eastern Siberia, Russian Federation), 2008, Kadlec J. , Chadima M. , L. Lisá , Hercman H. , Osintsev A. , And Oberhänsli H.

Botovskaya Cave is a typical example of a two-dimensional maze with a total length of explored passages exceeding 60 km, which represents the longest limestone cave system in the Russian Federation. The clastic cave sediments filling the cave passages differ in both mineral and mineral magnetic properties and were deposited under different hydrological conditions. The older portion of the clastic cave fills was derived from overlying sandstones, whereas the properties of younger cave sediments show closer affinity to the soils and weathering products originating on the plateau above the cave. The cave sediments underwent repeated periods of deposition and erosion during the Tertiary (?) and Pleistocene. The last catastrophic erosion event occurred in the cave more than 350 ka based on flowstone dating. Water seeping through the overlying sandstone body causes collapses of sandstone slabs from the cave passage ceilings, forming the youngest portion of the clastic cave fills.

230Th/U-dating of fossil corals and speleothems, 2008, Scholz D. , Hoffmann D.

Both marine and terrestrial carbonates can be precisely dated by U-series disequilibrium methods in the age range <600 ka (thousands of years). Here we focus on 230Th/U-dating of reef corals and speleothems. The requirements, potential but also the problems of 230Th/U-dating of both archives are presented and discussed. Fossil reef corals are used as indicators for past sea level fluctuations and as high-resolution palaeoclimate archives. These applications require precise and accurate dating, which can be achieved using 230Th/U-dating. However, many fossil corals show evidence for post-depositional open-system behaviour. This limits the accuracy of 230Th/U-ages of fossil corals rather than the analytical precision. We present and discuss the currently available methods to identify altered corals and also review three recently developed open-system dating approaches. Speleothems are very important climate archives because they are found in most continental areas and can be used to investigate and directly compare spatially variable climate conditions. They usually show no evidence for open-system behaviour but may contain significant amounts of initial detrital 230Th. We discuss the currently available correction techniques and methods to derive the most reliable ages. Furthermore, we give an overview of the state of the art techniques for U-series isotopes measurements. 

Emine-Bair-Khosar Cave in the Crimea, a huge bone accumulation of Late Pleistocene fauna, 2013, Ridush Â. , Stefaniak K. , Socha P. , Proskurnyak Y. , Marciszak A. , Vremir M. , Nadachowski A.

The Crimean Mountains are well known from the abundance of Middle and Late Palaeolithic sites and palaeontological remains recovered from cultural layers in caves and rockshelters. The fossil-bearing deposits of Emine-Bair-Khosar Cave, located at the elevation of 1000 m on the Chatyrdag Plateau, yielded a very diverse and numerous vertebrate remains that widen the knowledge of Late Pleistocene faunal diversity in the Crimea. The assemblage comprised in total almost 50 species of vertebrates. Studies included geomorphological, geological and stratigraphic analyses as well AMS 14C dating. Faunal remains were present in ten palaeontological sites. The main bone accumulation (section Ba2) was deposited during Middle Valdai or Vytachiv (MIS 3) interstadial, and including a long time gap, to the end of the Pleistocene and the Holocene. Comparison of the Emine-Bair-Khosar fauna with vertebrate faunas of other Crimean sites showed a remarkable stability in the faunal composition and frequency during the whole MIS 3 interstadial. Steppe and other open-country species dominated in the compared assemblages, while boreal-tundra species were far less numerous. Inhabitants of forests, including red deer and some rodents, were stable members of fossil assemblages.

GLACIER ICE-CONTACT SPELEOGENESIS, 2013, Lauritzen S. E. Skoglund R. Ø, .

 

The classic hypothesis of G. Horn’s (1935) subglacial speleogenesis as an explanation of the relatively small diameter cave conduits in the Scandinavian marble stripe karst is reviewed. Recent work, including accurate cave mapping and morphological analysis, radiometric dating of cave deposits, chemical kinetics experiments and computer simulations have challenged the old theory. Scandinavia has relatively small caves that often have surprisingly high ages, going beyond the limit of Th/U dating. The high ages are apparently compensated by correspondingly slow wall retreat rates in the icecontact regime, and longer periods when the caves were inactive. Ice-contact speleogenesis varied in time and space, in pace with waxing and waning of wet-based ice. Maze or labyrinth morphology appears as a characteristic feature of caves ascribed to these processes.

ISOTOPIC STUDIES OF BYPRODUCTS OF HYPOGENE SPELEOGENESIS AND THEIR CONTRIBUTION TO THE GEOLOGIC EVOLUTION OF THE WESTERN UNITED STATES, 2014, Polyak V. J. , Asmerom Y. , Hill C. A. , Palmer A. N. , Provencio P. P. , Palmer M. V. , Mcintosh W. C. , Decker D. D. , Onac B. P.

Hypogene speleogenesis in the western United States is associated with a deep source of water and gases that rise and mix with shallow aquifer water. Caves are formed below the surface without surface expressions (ie, sinkholes, sinking streams), and byproducts of speleogenesis are precipitated during the late phase of hypogene speleogenesis. These byproducts provide geochemical and geochronological evidence of a region’s geologic history and include gypsum rinds and blocks, elemental sulfur, halloysite-10Å, alunite, natroalunite, and other sulfur-related minerals. The following speleogenetic and speleothemic features are common: alteration rinds, crusts, mammillaries, folia, rafts, and cave spar. The types of hypogene speleogenesis vary and many can be expressed in space and time in relation to paleo-water tables. We identify two general types: (1) H2S-H2SO4-dominated speleogenesis that takes place predominantly near a paleo-water table (a few meters above and below), and (2) CO2-dominated speleogenesis that mostly takes place 10s to 100s of meters below a paleo-water table, with latest-stage imprints within meters of the water table.
The Kane caves in Wyoming, and the Guadalupe Mountains caves in New Mexico and West Texas, are examples of H2S-H2SO4-dominated speleogenesis (also known as sulfuric acid speleogenesis, SAS), where deposits of H2S- and H2SO4-origin are the obvious fingerprints. The Grand Canyon caves in Arizona and Glenwood Caverns in Colorado are examples of CO2-dominated systems, where H2SO4 likely played a smaller role (Onac et al., 2007). Deeper-seated geode-like caves, like the spar caves in the Delaware Basin area, are probably CO2-dominated, and have formed at greater depths (~0.5 ± 0.3 km) below paleo-water tables. Caves in the Black Hills, South Dakota are composite and complex and show evidence for multiple phases of hypogene speleogenesis. In areas such as the Grand Canyon region, these paleo-water tables, when they existed in thick carbonate rock stratigraphy and especially at the top of the thick carbonate rock strata, were likely regionally relatively flat in the larger intact tectonic blocks.
Geochemical studies of these deposits are providing information about the timing of speleogenesis through U-Th, U-Pb, and Ar-dating. In addition, tracer data from isotopes of C, O, S, Sr, and U are indicators of the sources of water and gases involved in speleogenesis. From these studies, novel canyon incision and landscape evolution interpretations are appearing in the literature. Beyond this, the study of these byproduct materials seems to show evidence that the deeply sourced water and gases involved in hypogene speleogenesis in the western United States are generated during tectonic and volcanic activity, and may be related to mantle processes associated with formation of the Rocky Mountains, Colorado Plateau, Basin and Range province, and Rio Grande Rift.