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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 reaction path modeling is a simulation approach to studying the chemical evolution of a (natural) system [22].?

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

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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 salinity (Keyword) returned 101 results for the whole karstbase:
Showing 1 to 15 of 101
Controversy over the great flood hypotheses in the Black Sea in light of geological, paleontological, and archaeological evidence, ,
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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]

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.

Donnees geomorphologiques sur la region de Fresh Creek, Ile Andros (Bahama), 1974,
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Bourrouilh F,
A geomorphological study of the east coast of Andros (Fresh Creek area) shows the existence of a paleotopography represented by low-altitude hills (few metres). This paleotopography is protected by the presence of a calcitic Quaternary crust which covers Pleistocene calcarenite.In the western part of the area, there are long woody axes, oriented NE-SW, parallel to the channels of the creek. They end at two kilometres from the coast, along which is a second kind of lower hills, orthogonal to the first.The first axes can be interpreted as megaripples as seen at the present time on modern deposits (on the Great Bahama Bank) and fossilized by the upper crust. The second direction is made by accretion ripples along the coast.The surface of the Bahamian calcarenite has been studied. The Bahamian karst presents two topographical forms: “blue holes” like those outside the island, which are 60-80 m in diameter and both sparse and deep; and “washtub” dolines; these are numerous and shallow, and, from low altitude, exhibit a honeycombed aspect on the surface. This karstic topography with dolines and blue holes is also seen through the water of the Creek the hard bottom of which is covered only here and there with a few centimetres of sediments. Hence, there is a submerged karstic topography, made of the same elements as the aerial karst, but submerged by the Holocene transgression. The present karstic relief, in relation with the different eustatic levels of the Quaternary, has begun 120,000 years ago, according to the isotopic ages, and might be composed by different steps, difficult to show now, in the topography.The blue holes in the interior of the island of young and little evolved karst, were formed more by solution than by collapse of the karstic caves, because of the absence of a real river to drain the Andros shelf at the time of low sea levels. Blue holes of the inside of the island, as they are called, with submarine openings, have the same salinity as the water of the creek (17.5 g/l). The dolines with very low salinity (0.7 g/l to 3.8 g/l) are filled with stromatolites and charophytes, slowly forming sediments made up essentially of high-magnesian calcite.It seems that the Andros Island karst can be compared with that of the Yucatan, where there are round and deep open pits, called cenote, of which the Bahamian equivalent would be the blue holes which were drowned by the Holocene transgression.ResumeSur l'ile Andros, zone emergee du Grand Banc de Bahama, l'auteur montre l'existence d'une paleotopographie comprenant deux categories de rides d'orientation differente et semblant fossilisee par une croute calcitique recente et l'existence d'un karst aux formes jeunes, bien qu'heritage d'un karst holocene en voie de submersion. Ces formes sont des “blue holes” ou trous bleus circulaires (60 a 80 m de diametre) et peu nombreux, et des dolines, dites en baquet. Dans ces dolines se deposent actuellement des croutes stromatolithiques calcitiques dont l'etude est faite par diffractometrie de rayons X et microscopie electronique a balayage

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".

A study of fresh water lens configuration in the Cayman Islands using resistivity methods, 1976,
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Bugg Sf, Lloyd Jw,
The problems of identifying the base of fresh water lenses in oceanic islands are discussed. A study carried out in the Cayman Islands is described in which the lens base is defined in relation to potable water standards and mapped using surface resistivity measurements with salinity profile controls in boreholes. Using depth-salinity ratios the piezometric surface is then determined. The technique is considered to provide a reliable cheap and rapid method of obtaining lens geometry in oceanic islands particularly where fairly homogeneous lithologies are present

Identification of the origin of oreforming solutions by the use of stable isotopes, 1977,
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Sheppard S. M. F. ,
SynopsisThe four major different types of water -- magmatic, metamorphic, sea water and/or connate, and meteoric water -- have characteristic hydrogen (D/H) and oxygen (18O/16O) isotope ratios. Applied to the analysis of isotopic data on hydrothermal minerals, fluid inclusions and waters from active geothermal systems, these ratios indicate that waters of several origins are involved with ore deposition in the volcanic and epizonal intrusive environment. Water of a single origin dominates main-stage mineralization in some deposits: magmatic -- Casapalca, Peru (Ag-Pb-Zn-Cu); meteoric -- Butte, Montana (Cu-Zn-Mn), epithermal deposits, e.g. Goldfield, Tonopah, Nevada (Ag-Au), Pachuca, Mexico (Ag-Au), San Juan Mountains District, Colorado (Ag-Au-Pb-Zn); sea water -- Troodos, Cyprus (Fe-Cu), Kuroko, Japan (Fe-Cu-Pb-Zn). Solutions of more than one origin are important in certain deposits (magmatic and meteoric -- porphyry copper and molybdenum deposits) and are present in many. In the porphyry Cu-Mo deposits the initial major ore transportation and alteration processes (K-feldspar-biotite alteration) are magmatic-hydrothermal events that occur at 750-500{degrees}C. These fluids are typically highly saline Na-K-Ca-Cl-rich brines (more than 15 wt % equivalent NaCl). The convecting meteoric-hydrothermal system that develops in the surrounding country rocks with relatively low integrated water/rock ratios (less than 0.5 atom % oxygen) subsequently collapses in on a waning magmatic-hydrothermal system at about 350-200{degrees}C. These fluids generally have moderate to low salinities (less than 15 wt % equivalent NaCl). Differences among these deposits are probably in part related to variations in the relative importance of the meteoric-hydrothermal versus the magmatic-hydrothermal events. The sulphur comes from the intrusion and possibly also from the country rocks. Deposits in which meteoric or sea water is the dominant constituent of the hydrothermal fluids come from epizonal intrusive and sub-oceanic environments where the volcanic country rocks are fractured or well jointed and highly permeable. Integrated water/rock ratios are typically high, with minimum values of 0.5 or higher (atom % oxygen) -- the magmatic water contribution is often drowned out'. Salinities are low to very low (less than 10 wt % equivalent NaCl), and temperatures are usually in the range 350-150{degrees}C. The intrusion supplies the energy to drive the large-scale convective circulation system. The sulphur comes from the intrusion, the country rocks and/or the sea water. Argillic alteration, which occurs to depths of several hundred metres, generated during supergene weathering in many of these deposits is isotopically distinguishable from hydrothermal clays

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

Carbonate rocks in the Black Sea basin: indicators for shallow water and subaerial exposure during Miocene--Pliocene time, 1979,
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Stoffers P. , Muller G. ,
Drilling in the Black Sea in general revealed three types of sediments: terrigenous, chemical, and biogenic. Terrigenous muds predominate in the Pleistocene whereas chemical sediments are abundant in the lower Pleistocene--Pliocene to Late Miocene sedimentary section. Biogenic constituents play a minor role only. The chemical sediments include calcite (lake chalk), Mg-calcite, aragonite, siderite and dolomite. Among these, the dolomites of Pliocene to Late Miocene age are most interesting. They were encountered in the two drill sites close to the Bosporus drilled in 2115 to 1750 m water depth, respectively. The dolomites show a great variety of criteria (e.g. intraclasts, algae mats, crusts, pellets, oolites), indicating a shallow water environment with occasional subaerial exposure and supratidal evaporitic conditions. The formation of these shallow water carbonates in the Black Sea is supposed to correlate with the Messinian salinity crisis in the Mediterranean

Palokarsts et palo-gomorphologie nognes des Alpes occidentales et rgions adjacentes, 1984,
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Julian M. , Nicod J.
NEOGENE PALEOKARSTS AND PALEO-GEOMORPHOLOGY IN THE WESTERN ALPS, JURA AND PROVENCE - This text is an attempt to confront our knowledge about the karsts and the problems of landscape evolution (tectonics, paleo-climates, sea level changes). Three periods had been studied: 1/ Early and Middle Miocene, with the development of chemical erosional surfaces and a prevailing sub-superficial karstic solution; 2/ the revolution of the Upper Miocene ("Rhodanian" tectonical phase and the salinity crisis of the Messinian), that caused the deepening of the karstic systems; 3/ the Plio-Villafranchian phase, favoured the production of terra-rossa and the evolution of the karstic caves, except during some dry periods during the Villafranchian.

La mise en exploitation des aquifres karstiques : quelques exemples algriens, 1987,
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Collignon, B
EXPLOITATION OF KARSTIC AQUIFERS IN ALGERIA - Some difficulties are specific of the karstic aquifers (hardness of the rocks, depth of the water table, scattering of the clefts). The new drilling techniques (downhole hammer) solve some of these difficulties and many mediterranean countries prospect now such aquifers. They contain very fresh waters, even in arid areas. The deep tube wells are now cheap and easy to elaborate. Depending of geological structure, the hydrogeological behaviour will be different (with more or less permanent water stocks). Some Algerian examples show how the development plan must be adjusted to this structure.

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Schneider W. , Geng A. Q. , Liu X. Z. ,
The lead-zinc ore deposits of the Siding-Gudan mineral subdistrict Guangxi are part of the large Nanling district of South China, and hosted in Devonian carbonate rocks. The ore bodies occur significantly along main faults and fault zones, and concentrate up to 300 meters above the Cambrian/Devonian unconformity. Connected with hydrothermal karst, size and volume of the ore bodies increase in proximity to this unconformity. Moving from the unaffected host rocks to the center of the ore bodies, four zones can be discriminated by the mineral assemblage (pyrite, sphalerite, galena) as well as by the degree of ordering, Ca/Mg, and Fe/Mn ratios of different dolomites. Homogenization temperatures range from 80-100-degrees-C (Presqu'ile dolomite) to 230-260-degrees-C (massive sphalerite). The sulfides reveal delta-S-34 = -20 to parts per thousand, and fluid inclusions display a salinity of 5-12 wt % equivalent NaCl. The diagenetic and hydrothermal history is similar to that of classic Mississippi Valley Type (MVT) sulfide mineral deposits as, for example, Pine Point in Canada. Mineralization and remobilization of the sulfides took place during a wide time span from late Paleozoic through Mesozoic. Both processes are considered as an interaction of saline basinal brines ascended from the adjoining dewatering trough, and magmatic-hydrothermal fluids of several magmatic-tectonic events

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Platt N. H. , Wright V. P. ,
Palustrine carbonates are shallow fresh-water deposits showing evidence of subaqueous deposition and subaerial exposure. These facies are common in the geological record. The intensity of modification is highly variable depending on the climate and the length of emergence. Palustrine limestones have previously been interpreted as marginal lacustrine deposits from fluctuating, low-salinity carbonate lakes, but several problems remain with existing facies models: 1) palustrine carbonates possess a lacustrine biota but commonly display fabrics similar to those of calcretes and peritidal carbonates; 2) the co-occurrence of calcrete horizons and karst-like cavities is somewhat unusual and appears to indicate contemporaneous carbonate precipitation and dissolution in the vadose zone; 3) the dominance of gray colors indicates water-saturation, apparently inconsistent with the evidence for strong desiccation overprint; 4) profundal lake deposits are generally absent from palustrine sequences, and sublittoral facies commonly make up only a small proportion of total thicknesses; 5) no good modem analogue has been identified for the palustrine environment. Analogy with the Florida Everglades suggests a re-interpretation of palustrine limestones, not as pedogenically modified lake margin facies but as the deposits of extensive, very shallow carbonate marshes. The distribution of environments in the Everglades is determined by the local hydrology, reflecting the control of seasonal water-level fluctuations and topography. Climate and topography were the main controls on deposition of ancient palustrine carbonates. As in peritidal sequences, aggradational cycles are capped by a range of lithologies (evaporites, desiccation and microkarst breccias, calcretes, lignite or coal horizons etc.), permitting interpretation of the climate. Careful analysis of lateral facies variations may permit reconstruction of subtle topography. Consideration of the Florida Everglades as a modem analogue for the palustrine environment has suggested the development of an exposure index for fresh-water carbonates

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Cathro Dl, Warren Jk, Williams Ge,
The Late Ordovician-Early Silurian Mallowa Salt of the Carribuddy Group, Canning Basin, north-west Australia, is the largest halite deposit known in Australia, attaining thicknesses of 800 m or more within an area of approximately 200 000 km2. Study of 675 m of drill core from BHP-Utah Minerals' Brooke No. 1 well in the Willara Sub-basin indicates that the Mallowa Salt accumulated within a saltern (dominantly subaqueous evaporite water body) that was subject to recurrent freshening, desiccation and exposure. Textures and bromine signatures imply a shallow water to ephemeral hypersaline environment typified by increasing salinity and shallowing into evaporitic mudflat conditions toward the top of halite-mudstone cycles (Type 2) and the less common dolomite/anhydrite-halite-mudstone cycles (Type 1). The borate mineral priceite occurs in the capping mudstones of some cycles, reinforcing the idea of an increasing continental influence toward the top of mudstone-capped halite cycles. The rock salt in both Type 1 and Type 2 cycles typically comprises a mosaic of large, randomly orientated, interlocking halite crystals that formed during early diagenesis. It only partially preserves a primary sedimentary fabric of vertically elongate crystals, some with remnant aligned chevrons. Intraformational hiati, halite karst tubes and solution pits attest to episodic dissolution. Stacked Type 2 cycles dominate; occasional major recharges of less saline, perhaps marine, waters in the same area produced Type 1 cycles. The envisaged saltern conditions were comparable in many ways to those prevailing during the deposition of halite cycles of the Permian Salado Formation in New Mexico and the Permian San Andres Formation of the Palo Duro Basin area in Texas. However, in the Canning Basin the cycles are characterized by a much lower proportion of anhydrite, implying perhaps a greater degree of continental restriction to the basin. The moderately high level of bromine in the Mallowa Salt (156.5 43.5 ppm Br for primary halite, 146.1 54.7 ppm Br for secondary halite) accords with evolved continental brines, although highly evaporative minerals such as polyhalite and magnesite are absent. The bromine levels suggest little or no dissolution/reprecipitation of primary halite and yet, paradoxically, there is little preservation of the primary depositional fabric. The preservation of early halite cements and replacement textures supports the idea of an early shutdown of brine flow paths, probably at burial depths of no more than a few metres, and the resultant preservation of primary bromine values in the secondary halite

The astronomical theory of climate and the age of the Brunhes-Matuyama magnetic reversal, 1994,
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Bassinot Fc, Labeyrie Ld, Vincent E, Quidelleur X, Shackleton Nj, Lancelot Y,
Below oxygen isotope stage 16, the orbitally derived time-scale developed by Shackleton et al. [1] from ODP site 677 in the equatorial Pacific differs significantly from previous ones [e.g., 2-5], yielding estimated ages for the last Earth magnetic reversals that are 5-7% older than the K/Ar values [6-8] but are in good agreement with recent Ar/Ar dating [9-11]. These results suggest that in the lower Brunhes and upper Matuyama chronozones most deep-sea climatic records retrieved so far apparently missed or misinterpreted several oscillations predicted by the astronomical theory of climate. To test this hypothesis, we studied a high-resolution oxygen isotope record from giant piston core MD900963 (Maldives area, tropical Indian Ocean) in which precession-related oscillations in [delta]18O are particularly well expressed, owing to the superimposition of a local salinity signal on the global ice volume signal [12]. Three additional precession-related cycles are observed in oxygen isotope stages 17 and 18 of core MD900963, compared to the composite curves [4,13], and stage 21 clearly presents three precession oscillations, as predicted by Shackleton et al. [1]. The precession peaks found in the [delta]18O record from core MD900963 are in excellent agreement with climatic oscillations predicted by the astronomical theory of climate. Our [delta]18O record therefore permits the development of an accurate astronomical time-scale. Based on our age model, the Brunhes-Matuyama reversal is dated at 775 10 ka, in good agreement with the age estimate of 780 ka obtained by Shackleton et al. [1] and recent radiochronological Ar/Ar datings on lavas [9-11]. We developed a new low-latitude, Upper Pleistocene [delta]18O reference record by stacking and tuning the [delta]18O records from core MD900963 and site 677 to orbital forcing functions

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Lauritzen S. E. , Bottrell S. ,
Along the Hornsund fault zone, South Spitsbergen (76-degrees-60'N), thermokarstic springs smell of H2S and display either growth of, or eject fragments of, organic slime. The temperature in individual springs varies between 4 and 15-degrees-C. Their rate of discharge is approximately 1 L s-1 to 18 m3 s-1, corresponding to a minimum temperature of 30-degrees-C within the base of the aquifer. The water, which contains a few ppm SO4(2-), 0.5 ppm S2-, and several thousand ppm NaCl, appears to be a mixture of turbid glacial meltwater and hot brine. Water chemistry and stable isotopes indicate that the salinity is not the result of simple dilution of modern seawater from the brackish zone beneath the coastal karst aquifer, but rather originates from a deep thermal brine component where concentrations and isotopic composition of various species are controlled by water-rock interaction in the source area of the brine. A value of DELTAdeltaS-34 of up to about 30 parts per thousand indicates that sulfide is a bioreduction product of sulfate. Scanning electron microscope (SEM) studies revealed bacteria and fungal hypha in the organic slime, and larger spherical particles (approximately 3.8 mum diameter) that display high concentrations of Fe and S. These findings demonstrate the presence of sulfate-reducing bacteria within the subpermafrost aquifer

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