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Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

Did you know?

That whaletail is a descender consisting of an aluminium block with slots, knobs and a safety gate [25].?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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Featured articles from other Geoscience Journals
Karst environment, Culver D.C.
Mushroom Speleothems: Stromatolites That Formed in the Absence of Phototrophs, Bontognali, Tomaso R.R.; D’Angeli Ilenia M.; Tisato, Nicola; Vasconcelos, Crisogono; Bernasconi, Stefano M.; Gonzales, Esteban R. G.; De Waele, Jo
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
Microbial mediation of complex subterranean mineral structures, Tirato, Nicola; Torriano, Stefano F.F;, Monteux, Sylvain; Sauro, Francesco; De Waele, Jo; Lavagna, Maria Luisa; D’Angeli, Ilenia Maria; Chailloux, Daniel; Renda, Michel; Eglinton, Timothy I.; Bontognali, Tomaso Renzo Rezio
Evidence of a plate-wide tectonic pressure pulse provided by extensometric monitoring in the Balkan Mountains (Bulgaria), Briestensky, Milos; Rowberry, Matt; Stemberk, Josef; Stefanov, Petar; Vozar, Jozef; Sebela, Stanka; Petro, Lubomir; Bella, Pavel; Gaal, Ludovit; Ormukov, Cholponbek;
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Your search for climatic-change (Keyword) returned 20 results for the whole karstbase:
Showing 1 to 15 of 20
Caves as archives of ecological and climatic changes in the pleistocene - the case of Gorham's Cave, Gibraltar, , Finlayson G, Finlayson C, Giles Pacheco F, Rodriguez Vidal J, Carrion Js, Recio Espejo Jm,

Continental Pleistocene Climatic Variations from Speleothem Age and Isotopic Data, 1974, Thompson Peter, Schwarcz Henry P. , Ford Derek C. ,
Speleothems from continental North American caves have been dated by means of the 230Th/234U method. Oxygen isotopic variations in the dated samples and phases of speleothem deposition can be interpreted in terms of climatic change. A glacial chronology constructed from the age and isotopic data lends support to the astronomical theory of climatic change

Messinian event in the black sea, 1979, Hsu Kenneth J. , Giovanoli Federico,
Three holes were drilled during the 1975 DSDP Leg 42B drilling the Black Sea. A section from Hole 380, at 2107 m water depth on the western edge of the abyssal plain, is 1074 m thick, and provides the most complete stratigraphic section. Dating of the sediments is based upon (1) fossil evidence from pollen, crustaceans, benthic foraminifera, and diatoms, (2) correlation with climatic changes and with unusual isochronous events that have been dated elsewhere, (3) paleomagnetic data, and (4) estimates of sedimentation rate.The history of Black Sea sedimentation recorded by the DSDP cores includes black shale sedimentation during the Late Miocene, followed by periodic chemical sedimentation from Late Miocene to Early Quaternary, and a change to dominantly terrigenous sedimentation from the Middle Quaternary. These hemipelagic and turbiditic sediments were deposited in lacustrine and brackish marine environments. The Messinian sediments, however, consist of stromatolitic dolomite, oolitic sands, and coarse gravels, deposited in supratidal and intertidal environments. The intercalation of the shallow-water sediments in a deep-water sequence suggests a drastic lowering of the water-level within the Black Sea basin during the Messinian so that the edge of the present abyssal plain was then the edge of a shallow lake.The Messinian draw-down phase of the Black Sea was in existence for about 100,000 years during the Lago-Mare stage of the salinity crisis. The evaporated waters formed an alkaline lake before it was drowned by a brackish marine transgression correlative to the Trubi transgression of the Mediterranean

The Lower Mississippian Mission Canyon Formation of central to southwestern Montana was deposited under dominantly semiarid to arid climatic conditions during Osagean to early Meramecian times. Following deposition, a pronounced climatic shift to more humid conditions occurred during middle Meramecian times. This climatic change is indicated by extensive, post-depositional karst fabrics and in the stable isotopic composition of early, meteoric calcite cements and diagenetically altered sediments. Early meteoric calcite cement in Mission Canyon limestones is generally nonluminescent and fills intergranular and fenestral porosity. Petrographic data indicate that this cement formed during intermittent subaerial exposure of the Mission Canyon platform during Osagean times. This initial generation of meteoric calcite cement has deltaO-18 values from -8.1 to -2.6 parts per thousand PDB. These data, and the oxygen isotopic values from nonluminescent skeletal grains and micrite in host limestone indicate that Osagean meteoric water may have had deltaO-18 values as low as -6.0 parts per thousand SMOW. A second generation of petrographically similar, but isotopically distinct, calcite cement fills biomolds and porosity within solution-collapse breccias in the Mission Canyon Formation. This cement generation postdates earlier nonluminescent Osagean calcite cement and is volumetrically most abundant near the top of the Mission Canyon Formation. DeltaO-18 values from these cements and from nonluminescent lime mudstone clasts and matrix in solution collapse breccias range from -13.8 to -8.2 parts per thousand PDB. These data indicate that Meramecian meteoric water may have had deltaO-18 values as low as - 12.0 parts per thousand. However, a higher-temperature burial overprint on the deltaO-18 values of the calcite cement cannot be ruled out. The more positive deltaO-18 values of the Osagean calcite components probably indicate warm and arid conditions during short-term [10(4)(?) yr) subaerial exposure along intraformational sequence and parasequence boundaries. The more negative deltaO-18 values from Meramecian calcite components and the extensive karst associated with the post-Mission Canyon unconformity may have developed because of cooler and more humid climatic conditions and possible rain-out effects during middle Meramecian times. A dramatic shift towards cooler and more humid climatic conditions may be coincident with the onset of major continental glaciation in the Early Carboniferous. The post-Mission Canyon unconformity has been attributed to a major fall in sea level that may have glacio-eustatic origins. Growth of continental glaciers during a time of global cooling would have caused migration of polar fronts further toward the paleoequator. These polar fronts in turn, would have pushed moist, mid-latitude weather systems toward the paleoequator, resulting in cooler, more humid conditions in low-latitude settings during ''icehouse'' times

The influence of climatic change on exposure surface development: a case study from the Late Dinantian of England and Wales, 1996, Vanstone Simon,
Exposure surfaces represent an integral part of Asbian-Brigantian cyclothemic platform carbonates in England and Wales. These are characterized by the association of clay palaeosols, calcrete and palaeokarst and in most instances would appear to have been polygenetic. Alternating calcrete-karst stratigraphies associated with individual exposure surfaces indicate that the climate changed from semi-arid to humid to semi-arid conditions during each sea-level fall/rise cycle. Lowstand intervals were humid and resulted in karstification of the cyclothem-top sediments and the formation of a mineral soil. In contrast, regressive/transgressive phases were semi-arid and resulted in calcretization of the emergent platform carbonates. The influence that climatic cyclicity had upon exposure surface development was modulated by variations in platform bathymetry, subsidence and spatial climatic variation, and platforms exhibit their own individual record of what was essentially an idealized sequence of events. As with the sea-level oscillations responsible for cyclothemic sedimentation, the climatic cyclicity is thought to be the product of orbital forcing and probably reflects either eccentricity-driven shifts in the locus of monsoonal precipitation, or precession-driven variations in monsoonal intensity. If precessional in origin, exposure surface development represents a single minimum to minimum excursion, some 20 ka in duration, whereas if eccentricity-driven this may have been appreciably longer. Nevertheless, the immature nature of the exposure surfaces suggests that emergence was probably only of the order of a few tens of thousands of years

A mineralogical analysis of karst sediments and its implications to the middle-late Pleistocene climatic changes on the Tibetan Plateau, 1998, Zhang D. D. ,
The minerals in various categories of Tibetan karst sediments were divided into three groups: carbonate, iron and silicate. The carbonate minerals, including calcite, aragonite and dolomite, consist mainly of speleothem, tufa and sinter. Most of the speleothems indicates wetter and warmer periods in early and middle Pleistocene, the youngest being 194,000 years old. The second formation of carbonate mineral, tufa, implies an arid period starting 91,000 years BP. The iron minerals, goethite and hematite, are often mixed up with cave alluvial sediments that are interbedded with flowstones, and the depression sediments. They indicate strong oxidizing environments during their deposition, which is absent at present. The clay minerals, specially kaolinite, were contained in cave alluvial, flowstone and the depression sediments as well. Combined with stratigraphic study and U-series dating, the mineral analysis shows that warmer and wetter climates, which were suitable for speleothem development, probably disappeared 200 ka ago, and drier and colder climates dominated this plateau since then

Petrography, strontium, barium and uranium concentrations, and strontium and uranium isotope ratios in speleothems as palaeoclimatic proxies: Soreq Cave, Israel, 1999, Ayalon A, Barmatthews M, Kaufman A,
The reconstruction of the palaeoclimate of the eastern Mediterranean region for the last 60 ka BP is based on the delta(18)O and delta(13)C variations of speleothems from Soreq Cave, Israel. Climatic conditions during most of the rime interval between 60 and 17 ka BP (the period equivalent to the last glacial) were relatively cold and dry, while they were warmer and wetter from 17 ka BP to the present. At similar to 17 ka BP, there was a major climatic change with a sharp increase in annual rainfall and temperature and a very wet period occurring between 8.5 and 7.0 ka BP. During the colder and drier period, large, detritus-free, preferentially oriented calcite crystals were deposited from slow-moving water. As a result of a sharp change in the hydrological regime at similar to 17 ka BP, fast-moving water started entrainment of the soil and carrying detrital material into the cave, and the calcite crystals deposited became small and anhedral. Coinciding with the petrographic and isotopic changes, a sharp drop occurred in the concentrations of strontium, barium and uranium, and in the ratios Sr-87/Sr-86 and (U-234/U-238)(0), which reached mini mum values during the wettest period. This drop reflects enhanced weathering of the soil dolomite host rock. During colder and drier periods, higher trace-element concentrations and higher isotopic ratios reflect an increase in the contribution of salts derived from exogenic sources (sea spray and aeolian dust), and a reduced contribution of weathering from the host dolomites

Spectral analysis of a 1000-year stalagmite lamina-thickness record from Shihua Cavern, Beijing, China, and its climatic significance, 1999, Qin Xiaoguang, Tan Ming, Liu Tungsheng, Wang Xianfeng, Li Tieying, Lu Jinpo,
Stalagmite laminae provide a high-resolution geological record of climate change. In this paper, moving spectral analysis is used to analyse a stalagmite lamina thickness record to study climatic variability. It was found that the dominant cycles of the lamina thickness sequence are 2, 3.3, 5-6, 10-12, 14-18, 133 and 194 years. Some of the cycles are the same as the cycles of modern climatic indices, such as the QBO (Quasi Biennial Oscillation) of 2 years, the QTO (Quasi Triple-year Oscillation) cycle of about 3.5 years, the QFO (Quasi Five-year Oscillation) cycle of 5-6 years and the QEO (Quasi Eleven-year Oscillation) cycle of 11 years. It was also found that there are different dominant cycles in different time periods. Usually, the dominant cycles are stronger in wet periods when the microlaminae are thicker. In dry periods, the microlaminae are thinner and the power of the dominant cycles is also weaker. Another feature is that the power of the dominant cycles and their long-term periods and frequencies appear to change. These phenomena are important for understanding the climatic changes in Beijing area over the last 1 ka

Role of mixing corrosion in calcite-aggressive H2O-CO2-CaCO3 solutions in the early evolution of karst aquifers in limestone, 2000, Gabrovsek F, Dreybrodt W,
Two cave-forming mechanisms in limestone are discussed currently. First, when two H2O-CO2-CaCO3 solutions, saturated with respect to calcite but with different chemical compositions mix, renewed aggressiveness to limestone dissolution occurs. This process called mixing corrosion [Bogli, 1964, 1980], in combination with linear dissolution kinetics, has been suggested as cave forming. Second, it has been shown that solely the action of nonlinear dissolution kinetics can generate extended karst conduits. This paper combines both mechanisms. By digital modeling of the evolution of the aperture widths of a confluence of two fractures into a third one it is shown that the first mechanism does not create large cave conduits. The combination of mixing corrosion and nonlinear kinetics, however, considerably intensifies karstification, compared to that of nonlinear kinetics solely. The times to terminate early evolution of karst are significantly reduced when the CO2 concentrations of the inflowing solutions differ by no more than 30%. We discuss the underlying mechanisms by inspection of the time dependence of the evolution of aperture widths, flow rates through them, and of the renewed undersaturation of the mixed solution at the confluence of two fractures. Finally, the evolution of a karst aquifer on a two-dimensional percolation network is modeled when mixing corrosion is present, and compared to that on an identical net with identical nonlinear dissolution kinetics, but mixing corrosion excluded. Large differences in the morphology of the net of cave conduits are found and also a reduction of the time of their evolution. From these findings we conclude that climatic changes, which influence the p(CO2) in the soil, can divert the evolving cave patterns

Karst lakes of the Protected Landscape Area - Biosphere Reserve Slovensky kras karst and Aggtelek National Park, 2001, Barancok P,
In the extent karst area belonging to the Protected Landscape Area - Biosphere Reserve Slovensky kras karst and Aggtelck National Park arc several lakes. They arc very significant biotopes. At present they arc extincted rapidly, their water surface is reduced, they are silted relatively quickly and they arc overgrown by wetland vegetation. In order to clarify the causes of their extinction the development of 3 takes of the area Slovensky kras karst - lakes Jastericicic jazero lake, Smradrave jazierko lake and Fardrova jama lake and 3 lakes of the area Aggtelck Karst - lakes Aggtelcki-to, voros-to and Kardos-to were evaluated. From the area Slovensky kras karst are well known 2 further lakes - Lucanske jazierko lake and Cierne jazero lake. Climatic changes and prevailingly negative impact of man have decisive influence on the development of all lakes in the mentioned area

Failure of an industrial wastewater lagoon in a karst terrain and remedial action, 2001, Memon B. A. , Azmeh M. M. ,
Failure of a wastewater lagoon, caused by development of a sinkhole underneath the lagoon at a site in the Lehigh River Valley near Allentown, Pennsylvania, allowed waste water to enter into the underlying karstified carbonate aquifer, a source of public water supply in the area. Identification of the contamination and development of an appropriate site-specific remediation plan required understanding of site geology, stratigraphy, hydrogeologic setting and aquifer characteristics. Information on site geology and hydrogeology, including aquifer geometry and matrix, occurrence and flow of groundwater were collected and evaluated. Core holes were drilled, geophysically logged, and correlated to define stratigraphy and structural controls to the movement of groundwater and pollutants. Monitoring wells were installed. Water level data collected on a continuous basis were used to determine the direction and gradient and also correlated with climatic changes to define amplitude of fluctuations of groundwater. Correlation of lithologic logs and interpretation of geophysical logs identified five water-producing zones separated by semi-confined layers within the carbonate aquifer. Water samples were collected from different water producing zones and analyzed to delineate vertical and horizontal extent of contamination. Pentaerythritol (PE), which was directly linked with the failure of lagoon, was identified as a pollutant in groundwater. PE was found to be present in the lower water-producing zones. Based on a geologic and hydrogeologic model of the site and understanding of flow regime and presence of PE in the lower water producing zones, a remedial plan (a pump-and-treat system) was developed and implemented to remediate the aquifer. This remedial action has reduced the PE level in groundwater and also created a pressure trough as a barrier to off-site migration

The environmental hazards of locating wastewater impoundments in karst terrain, 2002, Memon B. A. , Azmeh M. M. , Pitts M. W. ,
A wastewater storage lagoon failed due to the development of a sinkhole at a site in the Lehigh River valley in Allentown, Pennsylvania (PA). The polluted wastewater from the lagoon entered into the underlying aquifer and moved within a narrow pathway controlled by cracks, fissures, and solution channels within the karstified Allentown Formation of the Cambrian Period. The Allentown Formation serves as the principal aquifer for the public water supply of the area. To develop appropriate remedial measures, a thorough understanding of the geologic setting was required. Therefore, a geologic and hydrogeologic characterization of the area was completed, aerial photography and satellite imagery interpretations were performed, stratigraphic core holes were drilled and geophysically logged, and the data correlated to define structural control and movement of ground water and pollutants. A number of wells were drilled and constructed, and water levels were monitored on a continuous basis to correlate with climatic changes and determine the direction of flow. Water samples were collected periodically and analyzed to delineate the vertical and lateral extent of migration of pollutants. Five saturated (water-bearing) zones were identified within the bedrock based on the analysis of cores and interpretation of geophysical logs. Ground water in the lower zones is polluted; the concentration of pollution increases with depth. Monitoring stations were established in the creek, south of the site, to measure flow rate several times during different seasons, and at different reaches, to determine the losing and gaining sections of the creek. Pumping tests were conducted to determine hydraulic characteristics of the aquifer. Based on the hydrogeologic model of the karstified aquifer, flow regime and structural control, a plan of action was defined and initiated to remediate the aquifer. The ground water is being remediated using a pump and treat methodology. The cleanup effort is continuous and the pollutant level is fluctuating with an overall-declining trend. The application of this technology has also created a pressure trough, thereby controlling off the site migration of pollutants. (C) 2002 Published by Elsevier Science B.V

Speleothem rupture in karst: tectonic or climatic origin? U-Th dating of rupture events in Salamandre Cave (Gard, southeastern France), 2004, Ponsbranch, Hamelin B. , Brulhet J. , Bruxelles L. ,
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 Nimes 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

Palaeoclimatic implications of the growth history and stable isotope ([delta]18O and [delta]13C) geochemistry of a Middle to Late Pleistocene stalagmite from central-western Italy, 2004, Drysdale Rn, Zanchetta G, Hellstrom Jc, Fallick Ae, Zhao Jx, Isola I, Bruschi G,
The age structure and stable isotope composition of a stalagmite (CC1) from an upland cave in central-western Italy were studied to investigate regional response to global climatic changes. Four growth phases are constrained by 28 thermal ionization and multi-collector inductively coupled plasma mass spectrometry Th-U ages and reveal intermittent deposition through the period between Marine Isotope Stage (MIS) 11 and 3 (~380 and ~43 kyr). Most of the growth took place between ~380 and ~280 kyr, a period punctuated briefly by a hiatus in deposition through the glacial maximum of MIS 10. Growth was terminated abruptly at 280 kyr just prior to the MIS 8 glacial maximum. With a present-day chamber temperature of 7.5 [deg]C, the timing of hiatuses close to these glacial maxima point to freezing conditions at the time. No deposition was recorded through the entirety of MIS 7 and most of MIS 6, whilst two minor growth phases occurred at ~141-125 and ~43 kyr. Growth at 141 kyr indicates temperatures >0 [deg]C at a time when MIS 6 ice volumes were close to their maximum. High stable carbon isotope ([delta]13C) values (-2.8[per mille sign] to .1[per mille sign]) throughout the stalagmite's growth reflect a persistently low input of biogenic CO2, indicating that the steep, barren and alpine-like recharge area of today has been in existence for at least the last ~380 kyr. During MIS 9, the lowest [delta]13C values occur well after maximum interglacial conditions, suggesting a lag in the development of post-glacial soils in this high-altitude karst. The stable oxygen isotope ([delta]18O) trends match the main structural features of the major climate proxy records (SPECMAP, Vostok and Devils Hole), suggesting that the [delta]18O of CC1 has responded to global-scale climate changes, whilst remarkable similarity exists between CC1 [delta]18O and regional sea-surface temperature reconstructions from North Atlantic core ODP980 and southwest Pacific marine core MD97-2120 through the most detailed part of the CC1 record, MIS 9-8. The results suggest that CC1 and other stalagmites from the cave have the potential to capture a long record of regional temperature trends, particularly in regards to the relative severity of Pleistocene glacial stages

Lateglacial and Holocene sea level changes in semi-enclosed seas of North Eurasia: examples from the contrasting Black and White Seas, 2004, Kaplin Pavel A. , Selivanov Andrei O. ,
A comparison of the Black and White Seas, which differ in their tectonic, glacial and climatic history but which share a strong dependence upon limited water exchange with the world ocean, represents an opportunity for the identification of major factors controlling sea level changes during the Lateglacial and Holocene and for the correlation of these changes. Existing data were critically analyzed and compared with the results of geological, geomorphological and palaeohydrological studies obtained by the present authors during the past two decades.We conclude that glacioeustatic processes played a major role in relative sea level changes on most coasts of both areas. However, along several coastlines, other factors overwhelm glacioeustasy during some time intervals. In the Black Sea, water level rose from its minimum position, -100-120 m, at 18-17 ka BP, to -20-30 m at nearly 9 ka BP. In the White Sea, the decreasing trend in relative sea level is well illustrated on the Kola Peninsula and in Karelia, subject to glacioisostatic emergence. A drastic sea level fall from to -25 m occurred with the drainage of glacial lakes in the eastern White Sea (12.5-9.5 ka BP).The Black and White Sea histories changed drastically in the early Holocene or in the beginning of the middle Holocene (9.5-7.5 ka BP) due to the intrusion of water from the Mediterranean and the Barents seas, respectively. During this period, the White Sea developed under the strong influence of the formation of 'ice shelves' and 'dead ice' blocks, retreating glaciers, as well as of glacioisostatic and related processes. The Black Sea history, however, was determined by water exchange with the Mediterranean via the shallow Dardanelles and Bosporus straits (outflow from the Black Sea 10-9.5 ka BP and inflow from 9-7.5 ka BP according to various data), and, partially, by river discharge variations caused by climatic changes on the Russian Plain. The hypothesis of a catastrophic sea level rise from -120-150 to -15-20 m nearly 7550 calendar years BP is not supported by our data. Water intrusion from the Mediterranean was fast but not catastrophic.In the Black Sea, periods of high sea levels after the intrusion of Mediterranean waters are dated from four sedimentary complexes, Vityazevian, Kalamitian, Dzhemetian and Nymphaean, from nearly 7.5, 7-6, 5.5-4.5 and 2.2-1.7 ka BP, respectively. A fluctuating pattern of sea level change was established in the White Sea after the drainage of proglacial lakes and intrusion of ocean waters at the end of the early Holocene (nearly 8.5-8.2 ka BP). Major periods of sea level rise in the White Sea are dated from the late Boreal-early Atlantic (8.5-7.5 ka BP), late Atlantic (6.5-5.2 ka BP), middle Subboreal (4.5-4 ka BP) and middle Subatlantic (1.8-1.5 ka BP). Fluctuations of relative sea level during the middle and late Holocene were possibly on the order of several meters (from 3 to -2-3 m in the Black Sea and from 5 to -2-3 m in the White Sea). Lower estimates of regressive stages are principally derived from archaeological data on ancient settlements in tectonically submerging deltaic areas and cannot be regarded as reliable.Palaeohydrological analysis does not indicate that intensive (15-25 m or greater) sea level fluctuations were present in the Black Sea or in the White Sea during the middle and late Holocene. Instead, such analysis provides independent evidence to support the argument that significant differences in water level between the Black Sea and the Mediterranean could not be maintained for an extended period of time

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