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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. ...

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. ...

Speleology in Kazakhstan

Shakalov on 11 Jul, 2012
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 metamorphosis is a change in the form of a living thing as it matures, especially the drastic transformation from a larva to an adult [23]. see also pupa.?

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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
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Your search for sea-level changes (Keyword) returned 24 results for the whole karstbase:
Showing 1 to 15 of 24
Controversy over the great flood hypotheses in the Black Sea in light of geological, paleontological, and archaeological evidence, , Yankohombach Valentina, Gilbert Allan S. , Dolukhanov Pavel,
Legends describing a Great Flood are found in the narratives of several world religions, and the biblical account of Noah's Flood is the surviving heir to several versions of the ancient Mesopotamian Flood Myth. Recently, the story of the biblical deluge was connected to the Black Sea, together with the suggestion that the story's pre-Mesopotamian origins might be found in the Pontic basin [Ryan, W.B.F., Pitman, III, W.C., 1998. Noah's Flood: The New Scientific Discoveries About the Event That Changed History. Simon and Schuster, New York]. Based on the significance of this flood epic in the Judeo-Christian tradition, popular interest surged following publication of the idea.Currently, two Great Flood scenarios have been proposed for the Black Sea: (1) an Early Holocene event caused by catastrophic Mediterranean inflow at 7.2 ky BP (initial hypothesis of [Ryan et al., 1997. An abrupt drowning of the Black Sea shelf. Marine Geology 138, 119-126]) or 8.4 ky BP (modified hypothesis of [Ryan et al., 2003. Catastrophic flooding of the Black Sea. Annual Review of Earth and Planetary Science 31, 525-554.); and (2) a Late Pleistocene event brought on by Caspian influx between 16 and 13 ky BP [Chepalyga, A.L., 2003. Late glacial Great Flood in the Black Sea and Caspian Sea. GSA Annual Meeting and Exposition, 2-5 November 2003, Seattle, USA, p. 460]. Both hypotheses claim that the massive inundations of the Black Sea basin and ensuing large-scale environmental changes had a profound impact on prehistoric human societies of the surrounding areas, and both propose that the event formed the basis for the biblical Great Flood legend.This paper attempts to determine whether the preponderance of existing evidence sustains support for these Great Floods in the evolution of the Black Sea. Based upon established geological and paleontological data, it finds that the Late Pleistocene inundation was intense and substantial whereas the Early Holocene sea-level rise was not. Between 16 and 13 ky BP, the Late Neoeuxinian lake (the Late Pleistocene water body in the Pontic basin pre-dating the Black Sea) increased rapidly from ~-14 to -50 m (below the present level of the Black Sea), then rose gradually to ~-20 m by about 11 ky BP. At 11-10 ky BP (the Younger Dryas), it dropped to ~-50 m. When the Black Sea re-connected with the Sea of Marmara at about 9.5 ky BP, inflowing Mediterranean water increased the Black Sea level very gradually up to ~-20 m, and in so doing, it raised the salinity of the basin and brought in the first wave of Mediterranean immigrants. These data indicate no major drawdown of the Black Sea after the Younger Dryas, and they do not provide evidence for any catastrophic flooding of the Black Sea in the Early Holocene.In addition, available archaeological and paleoenvironmental evidence from the Pontic region reveal no recognizable changes in population dynamics between 14 and 6 ky BP that could be linked to an inundation of large magnitude [Dolukhanov, P., Shilik, K., 2006. Environment, sea-level changes, and human migrations in the northern Pontic area during late Pleistocene and Holocene times. In: Yanko-Hombach, V., Gilbert, A.S., Panin, N., Dolukhanov, P.M. (Eds.), The Black Sea Flood Question: Changes in Coastline, Climate, and Human Settlement. Springer, Dordrecht, pp. 297-318; Stanko, V.N., 2006. Fluctuations in the level of the Black Sea and Mesolithic settlement of the northern Pontic area. In: Yanko-Hombach, V., Gilbert, A.S., Panin, N., Dolukhanov, P.M. (Eds.), The Black Sea Flood Question: Changes in Coastline, Climate, and Human Settlement. Springer, Dordrecht, pp. 371-385]. More specifically, Mesolithic and early Neolithic archaeological data in southeastern Europe and Ukraine give no indications of shifts in human subsistence or other behavior at the time of the proposed catastrophic flood in the Early Holocene [Anthony, D., 2006. Pontic-Caspian Mesolithic and Early Neolithic societies at the time of the Black Sea Flood: A small audience and small effects. In: Yanko-Hombach, V., Gilbert, A.S., Panin, N., Dolukhanov, P.M. (Eds.), The Black Sea Flood Question: Changes in Coastline, Climate, and Human Settlement. Springer, Dordrecht, pp. 345-370; Dergachev and Dolukhanov, 2006. The Neolithization of the North Pontic area and the Balkans in the context of the Black Sea Floods. In: Yanko-Hombach, V., Gilbert, A.S., Panin, N., Dolukhanov, P.M. (Eds.), The Black Sea Flood Question: Changes in Coastline, Climate, and Human Settlement. Springer, Dordrecht, pp. 489-514]

Palaeoenvironment of lateritic bauxites with vertical and lateral differentiation, 1983, Valeton Ida,
Formation of lateritic bauxites of the type described in this paper occurs world-wide in Cretaceous and Tertiary coastal plains. The bauxites form elongate belts, sometimes hundreds of kilometres long, parallel to Lower Tertiary shorelines in India and South America and their distribution is not related to a particular mineralogical composition of the parent rock. The lateral movement of the major elements Al, Si, Fe, Ti is dependent on a high level and flow of groundwater. Varying efficiency of subsurface drainage produces lateral facies variations. Interfingering of marine and continental facies indicate a sea-land transition zone where the type of sediments also varies with minor tectonic movements or sea-level changes. A typical sediment association is found in India, Africa, South and North America. It consists of (i) red beds rich in detrital and dissolved material of reworked laterites, (ii) lacustrine sediments and hypersaline precipitates, (iii) lignites intercalated with marine clays, layers of siderite, pyrite, marcasite and jarosite, and (iv) marine chemical sediments rich in oolitic iron ores or glauconite. A model is developed to account for element distributions in lateritic bauxites in terms of groundwater levels and flow. Finally it is shown that many high-level bauxites are formed in coastal plains and that they are subsequently uplifted to their present altitude

DENUDATION CHRONOLOGY FROM CAVE AND RIVER TERRACE LEVELS - THE CASE OF THE BUCHAN KARST, SOUTHEASTERN AUSTRALIA, 1992, Webb J. A. , Fabel D. , Finlayson B. L. , Ellaway M. , Li S. , Spiertz H. P. ,
Detailed mapping of surface and underground karst features at Buchan, in eastern Victoria, has shown that the three river terraces along the Buchan River can be correlated with three levels of epiphreatic development in the nearby caves. Each level represents a stillstand in the denudational history of the area. Uranium series dating of speleothems and palaeomagnetic studies of cave sediments indicate that all three stillstands are more than 730 ka old. The periods of incision separating the stillstands were probably the result of active tectonic uplift. This contrasts with some northern parts of the Southeastern Highlands, which have been stable since the Eocene. The overall amount of incision and uplift at Buchan is small, indicating that the majority of scarp retreat in this section of the highlands must have occurred earlier. The denudation history of the Buchan area over the last 730 ka has seen only 2-3 m of incision, despite the major climatic and sea-level changes that have occurred in that time. Whereas most karst landscapes in the Northern Hemisphere have been extensively modified during the late Pleistocene, the Buchan karst was little affected, and its geomorphology has an older origin

Continental deposits and archaeological data in the Trieste Karst area (north-east Italy: evidence of sea-level changes and possible tectonic activity in the Late Pleistocene and Early Holocene, 1993, Boschian G,

A stepped karst unconformity as an Early Silurian rocky shoreline in Guizhou Province (South China), 1996, Jiayu R. , Johnson M. E. ,
There succeeded by marine strata, karst unconformities signify a former rocky coastline. Such relationships may help sort out relative sea-level changes and aspects of local geography controlling facies distribution. An exceptional example of an early Silurian karst shore is well exposed near the village of Wudang in central Guizhou Province, near the capital city of Guiyang in South China. Here the Lower Silurian Kaochaitien Formation oversteps 63 m of paleotopographic relief in limestones belonging to the Llanvirn Guniutan Formation and Caradoc to early Ashgill Huanghuachong Formation (Ordovician). The corresponding rise in sea level took place coeval with tectonic uplift, as confirmed by a regionally diachronous relationship in the Ordovician-Silurian boundary across a 250 km track from central to northern Guizhou Province. The change in sea level also fits with a global rise of sea level in late Aeronian (later Llandovery, early Silurian) time. Borings of the ichnofossil, Trypanites, are reported from the karst surface of the Huanghuachong Formation and Silurian strata hh sink holes in this unit over 5 m deep. The Silurian karst shoreline near Wudang is integrated with other regional data to construct a paleogeographic map covering the northern half of Guizhou Province

Two Ordovician unconformities in North China: Their origins and relationships to regional carbonate-reservoir characteristics, 1997, Liu B. , Wang Y. H. , Qian X. L. ,
The two unconformities developed on the tops of the Lower Ordovician Liangjiashan Formation (UF1) and the Middle Ordovician Majiagou- or Fengfeng Formation (UF2) are essential boundaries that controlled the formation and distribution of the Lower Paleozoic karst-related reservoirs. UF1 and UF2 have been interpreted as representing short-and long-terms of tectonic uplift, respectively, but new evidence led us to conclude that they were created by different original mechanisms and therefore the related reservoirs should be predicted in different ways. UF1 was commonly interpreted as the result of southern upwarping of the basement, but sequence-stratigraphic analysis supports its origin by eustatic sea-level changes. Spatially, the most favorable regional reservoirs controlled by UF1 should be located in the central area of North China, where the carbonate sediments experienced intensive shallow-subsurface dolomitization with following meteoric water leaching. UF2 was created by tectonic event which resulted in an intra-plate downward flexure and subsequent peripheral bulge. In the depression belt of central North China the younger strata (Fengfeng Fm) were protected, but along the bulge meteoric water eroded them. As a result, the potential regional reservoirs related to UF2 are likely to be distributed along the peripheral-uplift belts, especially around the remnant of the Fengfeng Formation. Based on the analysis of these two unconformities, the Early Paleozoic tectono-sedimentary evolution of North China Plate can be largely divided into four stages: (1) the Cambrian Period, characterized by eustatic sea-level rise and tectonic subsidence; (2) early stage of the Early Ordovician, characterized by eustatic-sea-level fall exceeding tectonic subsidence and development of UF1; (3) from the late stage of the Early Ordovician to the Middle Ordovician, featured by eustatic-sea-level rise and slow tectonic subsidence;(4) from the late stage of the Middle Ordovician to the Early Carboniferous, distinguished by vigorous tectonic uplift and development of UF2

Isolated carbonate platform of Caniego, Spain: A test of the latest Albian worldwide sea-level changes, 1997, Fernandezmendiola Pa, Garciamondejar J,
The upper Albian Caniego carbonate platform consists of a 20-m-thick unit of rudist- and coral-bearing limestones that crops out at the northern margin of the Mena diapir in northern Spain, The limestones were deposited on top of a slowly subsiding area, the Mena paleohigh, a diapiric-induced horst bounded by synsedimentary faults, The Caniego limestones originated in shallow warm tropical waters following a widespread marine transgression at the base of the foraminifera Rotalipora appenninica zone (ammonite Stoliczkaia dispar zone), Around the middle part of the appenninica zone the Caniego limestones underwent subaerial exposure and karst development, Fibrous calcite cements filled the bulk of the fissure-dike and dissolution cavities, Field, petrological, and geochemical data indicate that the fibrous calcites are meteoric flowstones, delta(18)O values in these cements range from -3 parts per thousand to -4.5 parts per thousand and delta(13)C values range from -7 parts per thousand to -14 parts per thousand (relative to the Peedee belemnite [PDB] standard), Thick wedges of nearshore shallow-marine siliciclastic sediments were deposited in paleotrough areas surrounding the Caniego paleohigh while the platform was subaerially exposed, The carbonate platform was drowned in early Cenomanian time and hardground-condensed facies developed during this period (Rotalipora brotzeni zone), Deeper water noncondensed marry sedimentation was reestablished in the mid-Cenomanian (Rotalipora reicheli zone), Comparison of the Iberian Caniego limestones with worldwide successions suggests a coincidence in the timing of platform formation emergence and drowning in several basins of different lithospheric plates, Nevertheless, an overall lack of coordination of sea-level histories from different basins may be related to tectonic movements of the lithospheric plates, Plate rearrangement is invoked as the primary control on relative sea-level changes and sequence development

Rapid sea-level changes at the close of the last interglacial (substage 5e) recorded in Bahamian island geology. Comment., 1997, Mylroie J. E.

Diagenetic History of Pipe Creek Jr. Reef, Silurian, North-Central Indiana, U.S.A, 2000, Simo J. A. , Lehmann Patrick J. ,
Calcite cements in the Silurian (Ludlovian) Pipe Creek Jr. Reef, north-central Indiana, are compositionally zoned with characteristic minor-element concentrations and stable-isotope signatures, and were precipitated in different diagenetic environments. Superposition and crosscutting relationships allow us to group cement zones and to relate them to the sequence stratigraphic evolution of the reef. Pipe Creek Jr. Reef grew in normal marine waters, with the reef top high (greater than 50 m) above the platform floor. Flank facies are volumetrically important and are preserved largely as limestone, in contrast to most dolomitized Silurian reefs in the midcontinent. Syndepositional marine cements fill primary porosity and synsedimentary fractures and are interlayered with marine internal sediment. Now low-magnesium calcite, their isotopic compositions are similar to those of depositional grains and cements estimated to have precipitated from Ludlovian sea waters. Depositional porosity was reduced by 75% by the precipitation of these syndepositional cements, which stabilized the steeply dipping flank slope. Postdepositional, clear calcite cements are interpreted as shallow-phreatic and burial cements on the basis of their relationship to periods of karstification and fracturing. Shallow-phreatic cements, with concentric cathodoluminescent (CL) zonation, precipitated in primary pores and are postdated by fractures and caves filled with Middle Devonian sandstone. CL zonal boundaries are sharp, and some, near a major stratigraphic unconformity, show evidence of dissolution. The volumetric abundance of the individual CL zones varies in the reef, indicating a complex superposition of waters of varying chemistry and rock-water interaction that are probably related to relative sea-level changes. This important aspect of the reef stratigraphy is recorded only by the diagenetic succession, because evidence of earlier sea-level changes is removed by a major later regional unconformity. Burial cements are the youngest diagenetic feature recognized, and they rest conformably or unconformably over older cements. They exhibit both concentric CL zonation and sectoral zoning, they are ferroan to nonferroan, and they contain thin sulfide zones along growth-band boundaries. Their isotopic compositions do not overlap with shallow-phreatic or marine cement values. Degraded oil postdates burial cements, and is composed of the same sterane class as the Devonian-age Antrim Shale, the probable source rock. This source contrasts with that of reef reservoirs in the Michigan Basin, where Silurian strata are commonly the hydrocarbon source

Evolution of river network at the 'Cevennes-Grands Causses' transition: Consequences for the evaluation of uplift, 2001, Camus H,
The Mediterranean catchment of the Cevennes (S. France) presents deep incision of the river network (fig. 1 and 2). Combined geomorphology and analyses of the residual sedimentary formations allows to reconstruct a complex history of river network evolution, including capture of tributaries of the Herault River (fig. 1, 2 and 3). The history of uplift of the upstream drainage area could be estimated from the provenance studies of the fluvial and karstic deposits, however river incision is also controlled sea-level changes and differential erosion, which makes reconstruction more complex. Allochthonous clasts types Analyses of allochtonous deposits on the Grands Causses surface reveals different origin for sediments from the hill top and the Airoles valley (fig. 4b), which was previously unrecognised. Facies 1 is found on the highest points of the Grands Causses surface (well sorted rounded quartz pebbles in red shale matrix) it corresponds to a weathered residual sediments (dismantling of an ancient cover). Facies 2 is found on the slope of the Airoles Valley (fig. 7). It consists of alluvial crystalline poorly sorted clasts with outsized clasts (up to 50cm) of quartz-vein, schists in a matrix of shales and sand (weathered granite). Between the hill tops and the Airoles Valley, karstic network presents a sediment fill with clasts reworked from facies I and facies 2 (fig. 6). Airoles valley model : an example of diachronic formation of drainage network The Airoles dry valley stretches on the Grands Causses from the north (700 m) to the south into the present thalweg line of the Vis canyon (500 m) (fig. 1b & 3). Crystalline deposits witness an ancient catchment in the Cevennes. Presently, the catchment in the crystalline basement is disconnected and captured by the Arre River flowing eastwards (fig. 3 & 4a). The profile of the Airoles abandoned valley connects with the present Vis Canyon, therefore, at the time of capture, incision of the Vis canyon had reached its present altitude (fig. 4a). The geomorphologic evolution of this area took place in three stages (fig. 8). 1) The Grands Causses acted as piedmont for the crystalline highlands of the Massif Central (fig. 8A). A latter karstic evolution (tropical climate) allowed the weathered residual sediments (facies 1) (fig. 8A). 2) Incision of the Vis karstic canyon implies that the Herault incision and terraces (facies 2) (fig, 8B) of the Airoles valley occurred during this stage. 3) The Arre valley head propagates westward by regressive erosion and finaly captured the Airoles river crystalline catchment (fig. 8C). Consequence for the Cevennes uplift and hydrographic network development Although the values of present vertical incision in the Vis canyon and in the Arre valley are similar, but they achieved at different time. In addition, the narrow and deep canyon of the Vis is due to vertical incision from the karstic surface of the Grands Causses, whereas the Arre wide valley results from (a younger) lateral slops retreat from a low Herault base-level. The Vis karstic canyon developed in a similar way to the major karstic canyons of both Mediterranean and Atlantic catchment (i.e. Tarn). This rules out a Messinian Mediterranean desiccation as incision driving mechanism and suggests tectonic uplift of the Cevennes and surrounding areas. The Tam being already incised by 13 My [Ambert, 1990], it implies a Miocene age for the incision. Conclusion The amplitude of the vertical incision cannot therefore be used in a simple way to interpret the uplift history of the basement. Consequently, geomorphologic analysis appears to be a prerequisite to distinguish the part played by each factor, and to select the site of uplift measurement

Karst development on carbonate islands, 2003, Mylroie J. E. , Carew J. L.

Karst development on carbonate platforms occurs continuously on emergent portions of the platform. Surficial karst processes produce an irregular pitted and etched surface, or epikarst. The karst surface becomes mantled with soil, which may eventually result in the production of a resistant micritic paleosol. The epikarst transmits surface water into vadose pit caves, which in turn deliver their water to a diffuse-flow aquifer. These pit caves form within a 100,000 yr time frame. On islands with a relatively thin carbonate cover over insoluble rock, vadose flow perched at the contact of carbonate rock with insoluble rock results in the lateral growth of vadose voids along the contact, creating large collapse chambers that may later stope to the surface.
Carbonate islands record successive sequences of paleosols (platform emergence) and carbonate sedimentation (platform submergence). The appropriate interpretation of paleosols as past exposure surfaces is difficult, because carbonate deposition is not distributed uniformly, paleosol material is commonly transported into vadose and phreatic voids at depth, and micritized horizons similar in appearance to paleosols can develop within existing carbonates.
On carbonate islands, large dissolution voids called flank margin caves form preferentially in the discharging margin of the freshwater lens from the effects that result from fresh-water/salt-water mixing. Similarly, smaller dissolution voids also develop at the top of the lens where vadose and phreatic fresh-waters mix. Independent of fluid mixing, oxidation of organic carbon and oxidation/reduction reactions involving sulfur can produce acids that play an important role in phreatic dissolution. This enhanced dissolution can produce caves in fresh-water lenses of very small size in less than 15,000 yr. Because dissolution voids develop at discrete horizons, they provide evidence of past sea-level positions. The glacio-eustatic sea-level changes of the Quaternary have overprinted the dissolutional record of many carbonate islands with multiple episodes of vadose, fresh-water phreatic, mixing zone, and marine phreatic conditions. This record is further complicated by collapse of caves, which produces upwardly prograding voids whose current position does not correlate with past sea level positions.
The location and type of porosity development on emergent carbonate platforms depends on the degree of platform exposure, climate, carbonate lithology, and rate of sea-level change. Slow, steady, partial transgression or regression will result in migration of the site of phreatic void production as the fresh-water lens changes elevation and moves laterally in response to sea-level change. The result can be a continuum of voids that may later lead to development solution-collapse breccias over an extended area.


The Barremian-Aptian Evolution of The Eastern Arabian Carbonate Platform Margin (Northern Oman), 2003, Hillgartner Heiko, Van Buchem Frans S. P. , Gaumet Fabrice, Razin Philippe, Pittet Bernard, Grotsch Jurgen, Droste Henk,
Carbonate platform margins are sensitive recorders of changes in sea level and climate and can reveal the relative importance of global and regional controls on platform evolution. This paper focuses on the Barremian to Aptian interval (mid Cretaceous), which is known for climatic and environmental changes towards more intensified greenhouse conditions. The study area in the northern Oman mountains offers one of the very few locations where the Cretaceous carbonate margin of the Arabian Plate can be studied along continuous outcrops. Our detailed sedimentological and sequence stratigraphic model of the platform margin demonstrates how major environmental and ecological changes controlled the stratigraphic architecture. The Early Cretaceous platform margin shows high rates of progradation in Berriasian to Hauterivian times followed by lower rates and some aggradation in the Late Hauterivian to Barremian. High-energy bioclastic and oolitic sands were the dominant deposits at the margin. Turbidites were deposited at the slope and in the basin. The Early Aptian platform margin shows a marked change to purely aggradational geometries and a welldeveloped platform barrier that was formed mainly by microbial buildups. The sudden dominance in microbial activity led to cementation and stabilization of the margin and slope and, therefore, a decrease of downslope sediment transport by turbidites. In the Late Aptian, large parts of the Arabian craton were subaerially exposed and a fringing carbonate platform formed. Seven Barremian to Early Albian large-scale depositional sequences reflecting relative sea-level changes are identified on the basis of time lines constrained by physical correlation and biostratigraphy. The reconstruction of the margin geometries suggests that tectonic activity played an important role in the Early Aptian. This was most likely related to global plate reorganization that was accompanied by increased volcanic activity in many parts of the world. Along the northeastern Arabian platform the associated global changes in atmospheric and oceanic circulation are recorded with a change in platform-margin ecology from an ooid-bioclast dominated to a microbial dominated margin. Time-equivalent argillaceous deposits suggest an increase in rainfall and elevated input of nutrients onto the platform. This process contributed to the strongly diminished carbonate production by other organisms and favored microbial activity. The platform margin may thus represent a shallow-marine response to the Early Aptian global changes, commonly associated with an oceanic anoxic event in basinal environments

Post-Miocene stratigraphy and depositional environments of valley-fill sequences at the mouth of Tampa Bay, Florida, 2003, Ferguson Tw, Davis Ra,
Post-Miocene sea-level low stands allowed rivers and karst processes to incise the exposed carbonate platform along the Gulf Coast of Florida. Few Miocene to mid-Pleistocene deposits survived erosion along the present coast except within incised valleys. Since their formation, these valleys have been filled and incised multiple times in response to sea-level changes. The thick sedimentary sequences underlying the mouth of Tampa Bay have been recorded as a range of depositional environments and multiple sea-level incursions and excursions during pre-Holocene time and subsequent to the accumulation of the Miocene carbonate sequences. Sediment analysis of cores collected from a north-south transect across the mouth of Tampa Bay has enabled the identification of lithofacies, ranging from well-sorted, quartz sand to dense, fossiliferous, phosphatic grainstone. These facies were deposited in freshwater, estuarine, and shallow, open marine environments. As a result of channel development and migration within the paleovalley, and cut-and-fill associated with individual transgressions and regressions, correlation of the lithofacies does not extend across the entire transect. Fining-upward sequences truncated by tidal ravinement surfaces that extend throughout the paleovalley can, however, be identified. Age determinations based on 14-C analysis, amino-acid racemization, and strontium isotope analysis dating of numerous samples yield ages of Miocene, Pliocene, early Pleistocene, and late Pleistocene, as well as Holocene for sequences that accumulated and were preserved in this valley-fill complex. Numerous inconsistencies in the stratigraphic organization of the age determinations indicate that there are bad dates, considerable reworking of shells that were dated, or both. For this reason as well as the lack of detailed correlation among the three relatively complete cores, it is not possible to place these strata in a sequence stratigraphic framework. (C) 2003 Elsevier B.V. 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.


Karst in Turkish Thrace: Compatibility between geological history and karst type, 2005, Ekmekci M,
Geographically, Thrace is a region located in southeastern Europe within the territories of Greece, Bulgaria and Turkey. In Turkish Thrace, karst occurs extensively in Eocene limestones, although some limited karst occurs in marble of the metamorphic series of Palaeozoic age. The karstification base is shallow to very shallow and most of the dolines and poljes have been captured by surface streams. Subsurface drainage has been changed to surface drainage in most parts of the region. Caves and cave relicts are concentrated mainly at three different altitudes, and almost all caves are horizontal or sub-horizontal. With these characteristics, Turkish Thrace hosts a distinct type of karst compared to that of other regions of Turkey, and particularly to the well-developed active Taurus karst. In this paper, the author discusses the major controls on karst evolution and consequently the occurrence of the present karst type with special emphasis on the geological history of the region. Tectonically, the area is weakly active, implying that a relatively steady continental uplift together with sea-level changes provided the source of the energy gradient required for karstification. The erosion base is controlled mainly by impermeable units. From the geological history of the region, it is concluded that no abrupt change in the energy gradient occurred due to continental uplift. However, fluctuation in sea level due to climate change has caused more sudden changes, particularly in erosion-base levels. This suggests that, in contrast to other karst provinces of Turkey, the impact of climate change has been more pronounced in this region. Reconstruction of karst evolution on the basis of the geological history of the region suggests that karstification processes have evolved without major interruption during the neotectonic period. Thus, the evolutionary character of the Thracian karst has produced relict karst with relatively local karst aquifers compared to those existing in the Taurus karst region. Morphological and hydrological aspects of the area indicate that karstification is in a cessation phase

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