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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. ...

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That dispersion, mechanical is see mechanical dispersion.?

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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 base metals (Keyword) returned 2 results for the whole karstbase:
Evaporites, brines and base metals: What is an evaporite? Defining the rock matrix, 1996, Warren J. K. ,
This paper, the first of three reviews on the evaporite-base-metal association, defines the characteristic features of evaporites in surface and subsurface settings. An evaporite is a rock that was originally precipitated from a saturated surface or near-surface brine in hydrological systems driven by solar evaporation. Evaporite minerals, especially the sulfates such as anhydrite and gypsum, are commonly found near base-metal deposits. Primary evaporites are defined as those salts formed directly via solar evaporation of hypersaline waters at the earth's surface. They include beds of evaporitic carbonates (laminites, pisolites, tepees, stromatolites and other organic rich sediment), bottom nucleated salts (e.g. chevron halite and swallow-tail gypsum crusts), and mechanically reworked salts (such as rafts, cumulates, cross-bedded gypsarenites, turbidites, gypsolites and halolites). Secondary evaporites encompass the diagenetically altered evaporite salts, such as sabkha anhydrites, syndepositional halite and gypsum karst, anhydritic gypsum ghosts, and more enigmatic burial associations such as mosaic halite and limpid dolomite, and nodular anhydrite formed during deep burial. The latter group, the burial salts, were precipitated under the higher temperatures of burial and form subsurface cements and replacements often in a non-evaporite matrix. Typically they formed from subsurface brines derived by dissolution of an adjacent evaporitic bed. Because of their proximity to 'true' evaporite beds, most authors consider them a form of 'true' evaporite. Under the classification of this paper they are a burial form of secondary evaporites. Tertiary evaporites form in the subsurface from saturated brines created by partial bed dissolution during re-entry into the zone of active phreatic circulation. The process is often driven by basin uplift and erosion. They include fibrous halite and gypsum often in shale hosts, as well as alabastrine gypsum and porphyroblastic gypsum crystals in an anhydritic host. In addition to these 'true' evaporites, there is another group of salts composed of CaSO4 or halite. These are the hydrothermal salts. Hydrothermal salts, especially hydrothermal anhydrite, form by the subsurface cooling or mixing of CaSO4- saturated hydrothermal waters or by the ejection of hot hydrothermal water into a standing body of seawater or brine. Hydrothermal salts are poorly studied but often intimately intermixed with sulfides in areas of base-metal accumulations such as the Kuroko ores in Japan or the exhalative brine deeps in the Red Sea. In ancient sediments and metasediments, especially in hydrothermally influenced active rifts and compressional belts, the distinction of this group of salts from 'true' evaporites is difficult and at times impossible. After a discussion of hydrologies and 'the evaporite that was' in the second review, modes and associations of the hydrothermal salts will be discussed more fully in the third review

The role of evaporites in the genesis of base metal sulphide mineralisation in the Northern Platform of the Pan-African Damara Belt, Namibia: geochemical and fluid inclusion evidence from carbonate wa, 2000, Chetty D, Frimmel He,
The Otavi Mountain Land is a base metal sulphide ore province in northern Namibia where deposits are hosted by platform carbonates of the Otavi Group in a foreland fold-and-thrust belt on the northern edge of the Pan-African Damara Belt. Deposits have been classified as the Berg Aukas- or Tsumeb-types, based on differences in ore association? stratigraphic position and geochemistry of ores and gangue carbonates. Mineralisation at these deposits is accompanied by carbonate alteration in the form of dolomite and calcite veins, carbonate recrystallisation, calcitisation and carbonate silicification. Based on cathodoluminescence imaging, trace and rare earth element (REE), O and C isotope, and fluid inclusion data, a series of carbonate generations, constituting wall rock alteration around the Tsumeb and Kombat (Tsumeb-type) and Berg Aukas (Berg Aukas-type) deposits, was established. Similar data obtained on the recently discovered Khusib Springs deposit indicate a strong affinity to Tsumeb-type deposits. Tsumeb-type deposits are distinguished from Berg Aukas-type deposits by having trace element and REE concentrations that are significantly higher in the alteration products compared to the carbonate host rocks. Only around Tsumeb-type deposits a relative enrichment in light REE is noted for the hydrothermal carbonate generations that are cogenetic with the main stage of mineralisation. Microthermometric results from fluid inclusions in carbonate alteration phases and associated quartz indicate relatively high salinity (17-33 wt% NaCl equivalent) for the main mineralising and subsequent sulphide remobilisation stages at the deposits investigated. Estimated mineralisation temperatures are significantly higher for Tsumeb-type deposits (370-405 degrees C) with early sulphide remobilisation in Tsumeb at 275 degrees C, whereas they are lower at Berg Aukas (up to 255 degrees C). Fluid inclusion leachate analysis suggests that most of the observed salinity can be ascribed to dissolved, predominantly Ca- and Mg-carbonates and chlorides with subordinate NaCl. Na-Cl-Br leachate systematics indicate a derivation of the fluid salinity from the interaction with evaporitic rocks en route. Tsumeb-type mineralisation is interpreted to be derived from fluids expelled during Pan-African orogeny in the more intensely deformed internal zones of the Damara Belt further south. When the high salinity fluids reached the carbonate platform after having scavenged high concentrations of base metals, base metal sulphide precipitation occurred in zones of high porosity, provided by karst features in the carbonate sequence. Results obtained for the Berg Aukas-type deposits emphasise their derivation from basinal brines, similar to Mississippi Valley-type deposits, and confirm that mineralisation of the Berg Aukas- and Tsumeb-types are both spatially and temporally distinct

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