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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 cone of impression is a rise of the potentiometric surface in the shape of a cone that develops around an injection well [22].?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms

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KarstBase a bibliography database in karst and cave science.

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 foraminifera (Keyword) returned 17 results for the whole karstbase:
Showing 1 to 15 of 17
Fauna of the brackish underground waters of Central Asia., 1965,
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Birstein Jakov Avadievich, Ljovuschkin S. I.
In the cave Kaptar-Khana (south-western Turkmenistan) was discovered a lake filled with water with a salinity of 11,68/oo. This lake is inhabited by a fauna of marine origin; Foraminifera (three species), Molluscs (Pseudocaspia ljovuschkini sp.n.), Harpacticoida (genera Ectinosoma, Schizopera and Nitocra), Isopoda (Microcharon halophilus sp.n.) and possibly Nematoda (Oncholaimidae). The majority of the discovered species are related to species of circum-Mediterranean origin. Geological data do not permit to consider this fauna as a relict of any of the Tertiary seas. The same applies to all other cases when animals of marine origin were discovered in subterranean waters of Central Asia (as for instance Microcharon kirghisicus Jank. on the shores of the lake Issyk-Kul). We can either admit a far greater anciennity of this fauna or an ability of its components to disperse very widely beyond the boundaries of marine transgressions.

New data on the Foraminifera of the groundwaters of Middle Asia., 1976,
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Mikhalevich Valeria I.
New data obtained during the expedition to Middle Asia (1973) essentially enlarge our knowledge of foraminifera living in underground waters. Seven new species were discovered in the wells of the Kara-Kum and Ust-Urt deserts. All of them contain cytoplasma. The wells are situated in the region of bedding of underground waters of the heightened salinity in the zone of balance of runoff and evaporation. The majority of the species described in our work like many of the species recorded from the underground waters earlier (Brodsky, 1928; Nikoljuk, 1968; Jankovskaja and Mikhalevich, 1972) belong to the genera living in coastal brackish parts of tropical seas. This fact confirms the supposition of Brodsky about the transition of the marine coastal foraminiferal fauna to underground habitats after the regression of the sea. This fauna is a part of the underground fauna called by Nalivkin (1965) "the planetar fauna of the new type".

Messinian event in the black sea, 1979,
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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

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Jones B. ,
Caymanite is a laminated, multicoloured (white, red, black) dolostone that fills or partly fills cavities in the Bluff Formation of the Cayman Islands. The first phase of caymanite formation occurred after deposition, lithification, and karsting of the Oligocene Cayman Member. The second phase of caymanite formation occurred after joints had developed in the Middle Miocene Pedro Castle Member. Caymanite deposition predated dolomitization of the Bluff Formation 2-5 Ma ago. Caymanite is formed of mudstones, wackestone, packstones, and grainstones. Allochems include foraminifera, red algae, gastropods, bivalves, and grains of microcrystalline dolostone. Sedimentary structures include planar laminations, graded bedding, mound-shaped laminations, desiccation cracks, and geopetal fabrics. Original depositional dips ranged from 0 to 60-degrees. Although caymanite originated as a limestone, dolomitization did not destroy the original sedimentary fabrics or structures. The sediments that formed caymanite were derived from shallow offshore lagoons, swamps, and possibly brackish-water ponds. Pigmentation of the red and black laminae can be related to precipitates formed of Mn, Fe, Al, Ni, Ti, P, K, Si, and Ca, which occur in the intercrystalline pores. These elements may have been derived from terra rossa, which occurs on the weathered surface of the Bluff Formation. Caymanite colours were inherited from the original limestone. Stratigraphic and sedimentologic evidence shows that sedimentation was episodic and that the sediment source changed with time. Available evidence suggests that caymanite originated from sediments transported by storms onto a highly permeable karst terrain. The water with its sediment load then drained into the subsurface through joints and fissures. The depth to which these waters penetrated was controlled by the length of the interconnected cavity system. Upon entering cavities, sedimentation was controlled by a complex set of variables

Isolated carbonate platform of Caniego, Spain: A test of the latest Albian worldwide sea-level changes, 1997,
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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

Platform-top and ramp deposits of the Tonasa Carbonate Platform, Sulawesi, Indonesia, 1997,
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Wilson M. E. J. , Bosence D. W. J. ,
This study presents a detailed facies analysis of shallow-water platform and ramp deposits of an extensive Tertiary carbonate platform. Temporal and spatial variations have been used to construct a palaeogeographic reconstruction of the platform and to evaluate controls on carbonate sedimentation The late Eocene to mid-Miocene shallow-water and outer ramp/basinal deposits of the Tonasa Carbonate Platform, from the Pangkajene and Jeneponto areas of South Sulawesi respectively, formed initially as a transgressive sequence in a probable backarc setting. The platform was dominated by foraminifera and had a ramp-type southern margin. Facies belts on the platform trend east-west and their position remained remarkably stable through time indicating aggradation of the platform-top. In comparison outer ramp deposits prograded southwards at intervals into basinal marls. Tectonics, in the form of subsidence, was the dominant control on accommodation space on the Tonasa Carbonate Platform. The location of barriers' and the resultant deflection of cross-platform currents, together with the nature of carbonate producing organisms also affected sedimentation, whilst eustatic or autocyclic effects are difficult to differentiate from the affects of tectonic tilting. Moderate- to high-energy platform top or redeposited carbonate facies may form effective hydrocarbon reservoirs in otherwise tight foraminifera dominated carbonates, which occur widely in SE Asia, and have not been affected by extensive porosity occlusion

High-resolution sequence stratigraphic correlation in the Upper Jurassic (Kimmeridgian)-Upper Cretaceous (Cenomanian) peritidal carbonate deposits (Western Taurides, Turkey), 1999,
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Altiner D, Yilmaz Io, Ozgul N, Akcar N, Bayazitoglu M, Gaziulusoy Ze,
Upper Jurassic (Kimmeridgian)- Upper Cretaceous (Cenomanian) inner platform carbonates in the Western Taurides are composed of metre-scale upward-shallowing cyclic deposits (parasequences) and important karstic surfaces capping some of the cycles. Peritidal cycles (shallow subtidal facies capped by tidal-Aat laminites or fenestrate limestones) are regressive- and transgressive-prone (upward-deepening followed by upward-shallowing facies trends). Subtidal cycles are of two types and indicate incomplete shallowing. Submerged subtidal cycles are composed of deeper subtidal facies overlain by shallow subtidal facies. Exposed subtidal cycles consist of deeper subtidal facies overlain by shallow subtidal facies that are capped by features indicative of prolonged subaerial exposure. Subtidal facies occur characteristically in the Jurassic, while peritidal cycles are typical for the Lower Cretaceous of the region. Within the foraminiferal and dasyclad algal biostratigraphic framework, four karst breccia levels are recognized as the boundaries of major second-order cycles, introduced for the first time in this study. These levels correspond to the Kimmeridgian-Portlandian boundary, mid-Early Valanginian, mid-Early Aptian and mid-Cenomanian and represent important sea level falls which affected the distribution of foraminiferal fauna and dasyclad flora of the Taurus carbonate platform. Within the Kimmeridgian-Cenomanian interval 26 third-order sequences (types and 2) are recognized. These sequences are the records of eustatic sea level fluctuations rather than the records of local tectonic events because the boundaries of the sequences representing 1-4 Ma intervals are correlative with global sea level falls. Third-order sequences and metre-scale cyclic deposits are the major units used for long-distance, high-resolution sequence stratigraphic correlation in the Western Taurides. Metre-scale cyclic deposits (parasequences) in the Cretaceous show genetical stacking patterns within third-order sequences and correspond to fourth-order sequences representing 100-200 ka. These cycles are possibly the E2 signal (126 ka) of the orbital eccentricity cycles of the Milankovitch band. The slight deviation of values, calculated for parasequences. from the mean value of eccentricity cycles can be explained by the currently imprecise geochronology established in the Cretaceous and missed sea level oscillations when the platform lay above fluctuating sea level. Copyright (C) 1999 John Wiley & Sons, Ltd

Development of the Scythian series in the Orlica anticline area (Sava folds), 2001,
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Anič, Ič, Bogoljub, Dozet Stevo, Ramovš, Anton

This paper deals with the development of the Scythian series in the Orlica anticline area. The Scythian beds of the Orlica anticline area lie discordantly upon various Carboniferous and Permian rocks. They are composed of five lithostratigraphic members: The older two members belong to the Lower Scythian, Seis beds respectively, and the younger three to the Upper Scythian, Campilian beds in the wider sense respectively. In the sandy beds of the Seis succession the pelecypods Eumorphotis venetiana and Anodontophora occur. On the other hand, in the Campilian beds the gastropods Natiria costata and Natica, as well as the pelecypod Myophoria costata and the foraminifera Meandrospira pusilla occur.

Last glacial-Holocene paleoceanography of the Black Sea and Marmara Sea: stable isotopic, foraminiferal and coccolith evidence, 2002,
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Aksu Ae, Hiscott Rn, Kaminski Ma, Mudie Pj, Gillespie H, Abrajano T, Yasar D,
Multi-proxy data and radiocarbon dates from several key cores from the Black Sea and Marmara Sea document a complex paleoceanographic history for the last ~30[punctuation space]000 yr. The Marmara Sea was isolated from both the Black Sea and the Aegean Sea during glacial periods when global sea-level lowering subaerially exposed the shallow sills at the Straits of Bosphorus and Dardanelles (i.e. lake stage), and reconnected through both straits during interglacial periods, when rise of global sea level breached the shallow sills (i.e. gateway stage). Micropaleontological data show that during the `lake stage' the surface-water masses in both the Marmara Sea and Black Sea became notably brackish; however, during the `gateway stages' there was a low-salinity surface layer and normal marine water mass beneath. Two sapropel layers are identified in the Marmara Sea cores: sapropels M2 and M1 were deposited between ~29.5 and 23.5 ka, and ~10.5 and 6.0 ka, respectively. Micropaleontological and stable isotopic data show that the surface-water salinities were reduced considerably during the deposition of both sapropel layers M2 and M1, and calculation using planktonic foraminiferal transfer functions shows that sea-surface temperatures were notably lower during these intervals. The presence of fauna and flora with Black Sea affinities and the absence of Mediterranean fauna and flora in sapropels M1 and M2 strongly suggest that communication existed with the Black Sea during these times. A benthic foraminiferal oxygen index shows that the onset of suboxic conditions in the Marmara Sea rapidly followed the establishment of fully marine conditions at ~11-10.5 ka, and are attributed to Black Sea outflow into the Marmara Sea since 10.5 ka. These suboxic conditions have persisted to the present. The data discussed in this paper are completely at odds with the `Flood Hypothesis' of Ryan et al. (1997), and Ryan and Pitman (1999)

Analysis of karst tufa from Guangxi, China, 2003,
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Franciskovicbilinski S, Bilinski H, Barisic D, Horvatincic N, Yuan Dx,
The paper presents an analysis of characteristic karst tufa from Guangxi, China, which has not been studied before. A comparison with tufa from Dinaric Karst of Croatia is discussed in view of the C-type climate. The major mineral is calcite. Minor minerals are quartz and dolomite, depending on location. The content of calcium carbonate varies from 65% to 92%, and that of magnesium carbonate from 0.03% to 1.77%. Among other elements, the most abundant are Fe, from 0.02% to 1.50%, and Ti, from 0.15% to 0.27%. Many other trace elements (V, Cr, Mn, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Y, Zr, Hg and Pb) are also present. Specific activity of radionuclides K-40, Th-232, Cs-137, Ra-226 and U-238 varies from sample to sample. Concentration of U in tufa is close to that reported for sedimentary carbonate. Low concentration Of Cs-137 indicates that this part of the world was not exposed to nuclear explosions. The concentration of Ra-226 is the highest in Mashan County. The ratio U-238/Ra-226 (0.21-0.71) in tufa from Mashan County is significantly lower than the theoretical value of 1. In 5 of the 11 studied samples, stable isotopes delta(13)C and delta(18)O were analyzed. They were dated by means of the C-14 method. One tufa sample originated in the Pleistocene and the others in the Holocene. Because all of the tufa samples contain traces of Na and K, and K < Na, the tufa from Guangxi belong to the CO2-outgassing 'N' type according to the classification of Liu and He (1994)

Lower carboniferous (late Visean) platform development and cyclicity in southern Ireland: Foraminiferal biofacies and lithofacies evidence, 2003,
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Gallagher Sj, Somerville Id,
The stratigraphy of several well exposed late Visean carbonate successions in southern Ireland have been correlated using high resolution foraminiferal/algal biostratigraphy and detailed biofacies analysis. This study has revealed that during the lower late Visean (early Asbian) time platform mudbank and intrabank facies were deposited on a rimmed ramp that dipped southward. By upper late Visean (late Asbian to Brigantian) time, well bedded carbonates were deposited on a shallow, unrimmed platform expanse that prograded southward through a series of shallowing-upward minor cycles. Within the late Asbian successions numerous minor cycles (2-15 m thick) occur that contain distinctive lithofacies and three distinct foraminiferal biofacies. The top of these cycles can usually be identified by palaeokarst surfaces with relief of to 0.5 m associated with pedogenic features and fissures indicating initial palaeocave-forming processes. Deposits on these emergent boundary surfaces include thick palaeosols (up to I in thick) and eroded boulders of the underlying karst surfaces. The lower transgressive facies of each minor cycle often began with the deposition of shallow-water, subtidal, algal-rich limestone containing diverse foraminiferal biofacies (Biofacies type 2). New foraminiferal taxa may appear in this part of the cycle. Towards the middle part of each cycle deeper water, subtidal, foraminiferal biofacies occur, but with no significant first appearance data. The biofacies at this level in the cycle are often algal-poor limestone rich in bryozoans or crinoids (Biofacies type 1). Biostratigraphically important foraminiferal taxa often first appear or reappear in low diversity assemblages toward the top of most cycles in shallower water grainstone microfacies (Biofacies type 3) rich in dasycladacean algae

Dolomites in SE Asia -- varied origins and implications for hydrocarbon exploration, 2004,
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Carnell Ajh, Wilson Mej,
Carbonates in SE Asia range in age from Palaeozoic to Recent, but are most important as reservoirs in the Neogene where they comprise a major target for hydrocarbon exploration (e.g. Batu Raja Formation, South Sumatra, Sunda and Northwest Java basins). Carbonates of pre-Tertiary, Palaeogene and Neogene age all show a strong diagenetic overprint in which dolomite occurs as both cementing and replacive phases associated with variable reservoir quality. This paper reviews published data on the occurrence and types of dolomites in SE Asian carbonates, and considers the models that have been used to explain the distribution and origin of dolomite within these rocks. Pre-Tertiary carbonates form part of the economic basement, and are little studied and poorly understood. Although some, such as in the Manusela Formation of Seram, may form possible hydrocarbon reservoirs, most are not considered to form economic prospects. They are best known from the platform carbonates of the Ratburi and Saraburi groups. in Thailand, and the oolitic grainstones of the Manusela Formation of Seram. The Ratburi Group shows extensive dolomitization with dolomite developed as an early replacive phase and as a late-stage cement. Palaeogene carbonates are widely developed in the region and are most commonly developed as extensive foraminifera-dominated carbonate shelfal systems around the margins of Sundaland (e.g. Tampur Formation, North Sumatra Basin and Tonasa Formation, Sulawesi) and the northern margins of Australia and the Birds Head microcontinent (e.g. Faumai Formation, Salawati Basin). Locally, carbonates of this age may form hydrocarbon reservoirs. Dolomite is variably recorded in these carbonates and the Tampur Formation, for example, contains extensive xenotopic dolomite. Neogene carbonates (e.g. Peutu Formation, North Sumatra) are commonly areally restricted, reef-dominated and developed in mixed carbonate-siliciclastic systems. They most typically show a strong diagenetic overprint with leaching, recrystallization, cementation and dolomitization all widespread. Hydrocarbon reservoirs are highly productive and common in carbonates of this age. Dolomite is variably distributed and its occurrence has been related to facies, karstification, proximity to carbonate margins and faults. The distribution and origin of the dolomite has been attributed to mixing-zone dolomitization (commonly in association with karstic processes), sulphate reduction via organic matter oxidation, and dewatering from the marine mudstones that commonly envelop the carbonate build-up. Dolomite has a variable association with reservoir quality in the region, and when developed as a replacive phase tends to be associated with improved porosity and permeability characteristics. This is particularly the case where it is developed as an early fabric-retentive phase. Cementing dolomite is detrimental to reservoir quality, although the extent of this degradation generally reflects the abundance and distribution of this dolomite. Dolomitization is also inferred to have influenced the distribution of non-hydrocarbon gases. This is best documented in North Sumatra where carbon dioxide occurs in quantities ranging from 0 to 85%. There are a number of possible mechanisms for generating this CO2 (e.g. mantle degassing), although the most likely source is considered to be the widely dolomitized Eocene Tampur Formation that forms effective basement for much of the basin. High heat flows are suggested to have resulted in the thermogenic decomposition of dolomite with CO2 produced as a by-product

Sequence Biostratigraphy of Prograding Clinoforms, Northern Carnarvon Basin, Western Australia: A Proxy for Variations in Oligocene to Pliocene Global Sea Level?, 2004,
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Moss Graham D. , Cathro Donna L. , Austin James A. Jr. ,
Sequence biostratigraphic analyses from five industry wells in the Northern Carnarvon Basin (NCB), Western Australia, are tied to seismic stratigraphic interpretations from a set of 3D and 2D seismic data. Distribution patterns of [~]286 benthic and 73 planktonic foraminiferal taxa in sidewall cores and ditch cuttings from Eocene to Pliocene intervals are documented and supplemented with observations of other fossil groups (e.g., fragments of ostracodes, bryozoans, corals, and mollusks) and lithological components such as calcite cement and quartz sand. Preservation of foraminiferal assemblages is extremely variable in latest Eocene to Pliocene stratigraphy, depending upon the location of wells and the interval investigated. Nonetheless, consistent, detectable faunal signals correlate between wells and with prominent seismic horizons and sequences. The late Oligocene to middle Miocene is characterized by deeper-water benthic assemblages dominated by infaunal taxa and a high planktonic abundance. Stratigraphic events in the middle Miocene, including turnover in benthic foraminifera, are interpreted to record a regional flooding event (equivalent to cycle Tejas B (TB) 2.3) at the beginning of the mid-Miocene climatic optimum ([~]16-14.5 Ma). Following this event, seismically defined geomorphic features include karstification on the shelf and incision on the clinoform front. All wells show a major transition to shallow-water, warm conditions on the shelf in the middle and late Miocene, with benthic assemblages dominated by larger foraminifera. This transition appears higher in more-basinward wells and appears to be a result of progradation. Geomorphic features in the late middle Miocene ([~]12 Ma) identified from 3D seismic analyses show an intensification of earlier gully formation, resulting in the development of submarine canyons. Detailed analyses of faunal patterns also provide evidence of higher-frequency sea-level fluctuations (0.5-3 Ma), not detected in the seismic stratigraphic patterns

Stable isotope analysis of the Cenomaniane Turonian (Late Cretaceous) oceanic anoxic event in the Crimea, 2005,
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Fisher J. K. , Price G. D. , Hart M. B. , Leng M. J.

Carbon and oxygen isotope data from Cenomaniane Turonian sediments from the southwest of the Crimea are presented. The sediments consist of limestones, marls and organic-rich claystones, the latter with total organic carbon values up to 2.6 wt. %, representing Oceanic Anoxic Event 2. A shift to more negatived 18 O values through the uppermost Cenomanian into the lowermost Turonian may be the result of warming; however, petrographic analysis shows that the samples have undergone a degree of diagenetic alteration. The carbon isotope data reveal a positive excursion fromw2.7&to a peak of 4.3&at the Cenomanian/Turonian boundary; values then decrease in the early Turonian. This excursion is comparable to those of other Cenomaniane Turonian sections, such as those seen in the Anglo-Paris Basin, and is thought to be due to global changes in the oceanic carbon reservoir. On this curve are a number of negatived 13 C excursions, just below the Cenomanian/Turonian boundary. It is suggested that these negative excursions are associated with the uptake of light carbon derived from the oxidation and deterioration of or-ganic material during localised exposure of the sediments to oxic or meteoric diagenetic conditions, possibly during sea-level fluctuations. 

Reconstruction of the paleoenvironmental changes around the Miocene-Pliocene boundary along a West-East transect across the Mediterranean, 2006,
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Pierre Catherine, Caruso Antonio, Blancvalleron Marie Madeleine, Rouchy Jean Marie, Orzsagsperber Fabienne,
In order to reconstruct the environmental changes at the end of the Messinian salinity crisis, a multidisciplinary study has been carried out with a high sampling resolution of the late Messinian-early Zanclean (Zone MPl 1) sediments along a West-East Mediterranean transect. The studied examples comprise sections from southern Spain (Vera/Almanzora), Balearic Basin (ODP Site 975), Tyrrhenian Basin (ODP Site 974), Sicily (Eraclea Minoa), Zakynthos (Kalamaki), Corfu (Aghios Stefanos), Crete (Aghios Vlasis). Previously analyzed sections from the Levantine Basin (Cyprus and ODP Sites 968 and 969) are used for comparison. The sections have been correlated using planktonic foraminiferal assemblages, sedimentological and stable isotope variations, and compared to the astronomical cyclicity defined in the Miocene-Pliocene boundary stratotype of Eraclea Minoa, Sicily. Variations of CaCO3 content, stable isotopes of carbonates ([delta]18O, [delta]13C), and foraminiferal assemblages indicate similar environmental transition at the Miocene-Pliocene boundary in all of the investigated sections.The latest Messinian deposits are barren of fossils or characterized by only reworked planktonic foraminifers, except for the sporadic presence of Ammonia tepida, brackish or lacustrine ostracods and brackish mollusks typical of the 'Lago-Mare' facies. The oxygen and carbon isotopic compositions of carbonates usually exhibit large variations with dominantly low [delta] values indicating freshwater dilution. The earliest Pliocene (MPl 1, cycle 1) shows a rapid and progressive increase of the [delta]18O values, which indicates the restoration of marine conditions after the Lago-Mare event. Normal marine environments were definitely established and stabilized at the top of cycle 1.These data confirm that the inflow of marine waters occurred contemporaneously within the whole Mediterranean at the base of Pliocene, although stable marine conditions occurred only about 20[no-break space]kyrs later

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