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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 experimental basin is a basin chosen for the thorough study of hydrological phenomena [16].?

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Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
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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
Calculating flux to predict future cave radon concentrations, Rowberry, Matt; Marti, Xavi; Frontera, Carlos; Van De Wiel, Marco; Briestensky, Milos
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Your search for triassic carbonate (Keyword) returned 8 results for the whole karstbase:
Paleoalpine karstification - The longest paleokarst period in the Western Carpathians (Slovakia), 1995, Cincura J, Kohler E,
The considerable areal extent and great thicknesses of Middle/Upper Triassic carbonate complexes influenced favourably the formation of karst during subaerial periods. The lower boundary of the Paleoalpine karst period is age-determined by the gradual emergence of the basement - during the Upper Cretaceous in the Central Western Carpathians and even earlier in the Inner Carpathians. The upper boundary can be dated by marine transgression The start of the transgression is not synchronous and it varies in a broad range from Upper Cretaceous to Upper Eocene and maybe even up to Oligocene/Miocene. The typical products of the period include typical karst bauxites filling karst cavities, ferri crusts, red clays, collapse and crackle breccias with speleothems, freshwater limestones or polymict conglomerates

Main features of the pre-Gosau paleokarst in the Brezovske Karpaty Mts. (Western Carpathians, Slovakia), 1998, Cincura J,
The considerable areal extent and great thickness of Middle/Upper Triassic carbonate sequences favourably influenced the development of paleokarst during the Paleoalpine karst period in the Brezovske Karpaty Mts. Carbonate formations provide data concerning the first-pre-Gosau-phase of the Paleoalpine karst period. Freshwater limestones, bauxites, reddish ferrugineous silty clays, Valchov Conglomerate, shallow doline-like depressions and deeper canyon-like forms represent the most important pre-Gosau karst sediments and forms

Origin and development of an old alpine cave (Zadlaźka jama, Julian Alps), 1999, Knez Martin, Slabe Tadej

The entrance into Zadlaźka jama lies in Maastrichtian limestone breccias at the extreme northern border of the Outer Dinarid tectonic unit; from the presence of Megalodontid shells it is presumed that the northern parts of the cave developed in Upper Triassic limestones. Tectonically the Cretaceous and also Triassic carbonates are strongly broken. Several systems of former water passages controlled by geological factors are found in the cave. Two of them are more distinctive: one developed along bedding-planes or at the contact of beds parallel to bedding and the other along fissures and faults which are transverse to local bedding. The cave is an anastomosis network system of initial tubes that develop into passages. The first and the most important factor was water that slowly flowed through the passages. Later the cave was filled by fine-grained sediments. Water flowed above them leaving above-sediment rocky features. The parts of the lower lying passages from which the sediments had been removed were shaped by fast water flow after the lowering of the underground water level. Relatively soon the cave remained hanging in the slope and was dry. Then the rocky perimeter was partly reshaped by condensation water.


Formation of dolomite mottling in Middle Triassic ramp carbonates (Southern Hungary), 2000, Torok A. ,
The Middle Triassic carbonates of the Villany Mountains were deposited on a homoclinal carbonate ramp. Many of the carbonates from the 700 m-thick sequence show partial or complete dolomitization. The present paper describes dolomites that occur in a limestone unit as irregular mottles and as pore- and fracture-filling cements. Replacement-type scattered dolomite rhombs in the mottles having inclusion-rich, very dull luminescent cores and limpid non-luminescent outer zones represent the initial phase of dolomitization. The isotopic composition of these dolomites (delta(13)C = .30 parts per thousand VPDB, delta(18)O = -3.60 parts per thousand VPDB) is similar to that of the calcitic micrite (delta(13)C = .6 parts per thousand VPDB, delta(18)O = -4.00 parts per thousand VPDB) indicating that no external fluids were introduced during dolomite formation. The elevated Sr content of the micrites implies that sediment was originally aragonite or high-Mg calcite. Dolomitization took place in the burial realm from a 'marine' pore-fluid in a partly closed system. Later fracture-related saddle dolomite reflects elevated formation temperatures and increasing burial. Five calcites were identified. Multiple generations of calcite-filled fractures were formed during burial diagenesis generally having dull or no luminescence (delta(13)C = .80 parts per thousand VPDB, delta(18)O = -6.40 parts per thousand VPDB). The latest phase calcites are related to karst formation, having a very negative isotopic composition (delta(13)C = -5.0 to -7.2 parts per thousand VPDB and delta(18)O approximate to -7.44 parts per thousand VPDB). The karst-related processes include dissolution, calcite precipitation and partial replacement of dolomites by complex zoned bright yellow calcite. The timing of dolomitization is uncertain, but the first phase took place in a partly closed system prior to stylolite formation. Late-stage saddle dolomites were precipitated during maximum burial in the Cretaceous. The dissolution of dolomites and karst-related calcite replacement was not earlier than Late Cretaceous. (C) 2000 Elsevier Science B.V. All rights reserved

KRASOVA JASKYNA PRYA V STIAVNICKYCH VRCHOCH - HYDROTERMALNA SPELEOGENEZA V KARBONATOVOM PODLOZI MIOCENNEHO STRATOVULKANU, 2011, Bella P. , Sucha V. , Gaal E. , Kodera P.

A cave of hydrothermal origin in crystalline limestone has been investigated near Sklene Teplice Spa in the Stiavnicke vrchy Mts. located in Central Slovakia. Metamorphozed Middle Triassic carbonate rocks occur as a horizon in pre-volcanic basement of Middle Miocene volcanic formations. The hydrothermal origin of studied cave is documented by spherical and irregural oval phreatic morphology sculptured by ascending thermal water, metamorphic type of the host rocks and their hydrothermal alteration, occurrence of large calcite and quartz crystals, and hydrothermal clays with three mineral smectite-kaolinite, illite and goethite associations. The primary phases of speleogenesis in the crystalline limestones was caused by hydrothermal processes linked either to the emplacement of granodiorite subvolcanic intrusions during the Late Badenian time or to epithermal system of the Late Sarmatian time in the central zone of the Stiavnica stratovolcano. The described cave presents the remarkable' example of hydrothermal limestone cave associated with Miocene volcanism and magmatic intrusions in Central Slovakia.
 


Fluid migration and porosity evolution in the Buda Hills, Hungary – selected examples from Triassic and Paleogene carbonate rocks/Dissertation submitted to the Ph.D. program for Geology and Geophysics at the Ph.D. School of Earth Sciences, Eötvös Lor, 2011, Poros, Zsófia

Porosity evolution of carbonates in the Buda Hills was the subject of this research. The aim was to provide an analogue for carbonate reservoirs that underwent multiphase diagenesis. Two major porosity types were recognized: 1) micro-porosity of powdered Triassic dolomites 2) cavernous and fracture porosity represented by the famous hypogenic cave system, hosted by Triassic and Paleogene carbonates. Powderization of dolomite is a general phenomenon in the Buda Hills, where its areal extent is exceptionally large compared to similar occurrences elsewhere in the world. Geochemistry and mineralogy of the dolomite remained constant throughout the disintegration. Powderization is absent at places where the Triassic dolomites are partially calcitized as a result of karst related dedolomitization. Since powderization was controlled by surface related processes and no geochemical changes were associated with it, disintegration of dolomite is interpreted as the result of sub-recent physical weathering, supposedly related to frost action.

Hypogenic caves are found along older calcite-barite-fluorite-sulphide veins, pointing to the fact that young cave-forming fluids migrated along the same fractures as the older mineralizing fluids did. Predominantly NNW–SSE strike of fractures concludes a latest Early Miocene maximum age for the fracture-filling minerals. Vein-calcite contains coeval primary, HC-bearing- and aqueous inclusions indicating that also HCs have migrated together with the mineralizing fluids. The coexistence of aqueous and HC inclusions permitted to establish the entrapment temperature (80°C) and pressure (85 bar) of the fluid and thus also the thickness of sediments, having been eroded since latest Early Miocene times, was calculated (800 m). Low salinity of the fluids (<1.7 NaCl eq. wt%) implies that HC-bearing fluids were diluted by regional karst water. Fluid inclusion studies also revealed that aggressive gases (e.g. CO2, H2S) were associated with HCs and that these gases may have played a role in dissolution of the carbonates. Based on the location of the paleo- and recent HC indications, identical migration pathways were reconstructed for both systems. It was proved that HC-bearing fluids have migrated northwestward from the basin east to the Buda Hills from the Miocene on. Due to the uplift related intensification of groundwater circulation, the proportion of hydrothermal fluids has diminished in favour of cold meteoric fluids. Establishment of the actual porosity of the Buda Karst initiated in Miocene times and earlier diagenetic history of the carbonates affected only the powderization of dolomite, and it had no direct effect on the localization of hypogenic caves.


Hydrodynamic modeling of a complex karst-alluvial aquifer: case study of Prijedor Groundwater Source, Republic of Srpska, Bosnia and Herzegovina, 2013, Polomčić Dušan, Dragišić Veselin, Živanović Vladimir

Middle Triassic fractured and karstified limestone and dolomite form a karst aquifer in the Sana River Valley near the town of Prijedor. As a result of intensive tectonic movements, carbonate rocks are mostly below the Sana River level, covered by younger Pliocene and alluvial deposits. The main source of groundwater recharge is infiltration from the Sana River through its alluvium over most of the aquifer. The main objective of the research reported in this paper was to evaluate the hydraulic relationships of the alluvial, Pliocene and karst aquifers in order to better understand the water supply potential of the karst aquifer. Although the use of hydrodynamic modeling is not very common with karst aquifers, the developed model provided significant and useful information on the groundwater budget and recharge type. The influence of fault zones and spatial anisotropy of the karst aquifer were simulated on the hydrodynamic model by varying permeability on the xand y­axes of the Cartesian coordinate system with respect to the fault, the main pathway of groundwater circulation. Representative hydraulic conductivities were Kx

 = 2.3·10­3

 m/s and Ky

 = 5.0·10­3

 m/s in the faults of Nw to SE direction, and Kx

 = 2.5·10­3

 m/s and Ky

 1.2·10­3

 m/s in the faults of Sw to NE trend. Model research showed that the karst aquifer can be used in the long term at maximal tested capacities and that current groundwater exploitation is not compromised in dry periods when the water budget depends entirely on recharge from the Sana River.


The fate of CO2 derived from thermochemical sulfate reduction (TSR) and effect of TSR on carbonate porosity and permeability, Sichuan Basin, China, 2015, Hao Fang, Zhang Xuefeng, Wang Cunwu, Li Pingping, Guo Tonglou, Zou Huayao, Zhu Yangming, Liu Jianzhang, Cai Zhongxian

This article discusses the role ofmethane in thermochemical sulfate reduction (TSR), the fate of TSR-derived CO2 and the effect of TSR on reservoir porosity and permeability, and the causes of the anomalously high porosity and permeability in the Lower Triassic soured carbonate gas reservoirs in the northeast Sichuan Basin, southwest China. The Lower Triassic carbonate reservoirs were buried to a depth of about 7000 m and experienced maximum temperatures up to 220 °C before having been uplifted to the present-day depths of 4800 to 5500 m, but they still possess porosities up to 28.9% and permeabilities up to 3360 md. The present-day dry gas reservoirs evolved from a paleo-oil accumulation and experienced varying degrees of TSR alteration as evidenced from the abundant sulfur-rich solid bitumens and varying H2S and CO2 concentrations. TSR occurred mainly within the oil and condensate/wet gas windows, with liquid hydrocarbons and wet hydrocarbon gases acting as the dominant reducing agents responsible for sulfate reduction, sulfur-rich solid bitumen and H2S generation, and calcite precipitation. Methane-dominated TSR was a rather late event and had played a less significant role in altering the reservoirs. Intensive H2S and CO2 generation during TSR resulted in calcite cementation rather than carbonate dissolution, which implies that the amount of water generated during TSR was volumetrically insignificant. 13C-depleted CO2 derived from hydrocarbon oxidation preferentially reacted with Ca2+ to form isotopically light calcite cements, and the remaining CO2 re-equilibrated with the 13C-enriched water–rock systems with its δ13C rapidly approaching the values for the host rocks, which accounted for the observed heavy and relatively constant CO2 δ13C values. The carbonate reservoirs suffered from differential porosity loss by TSR-involved solid bitumen generation and TSR-induced calcite and pyrite precipitation. Intensive TSR significantly reduced the porosity and permeability of the intervals expected to have relatively high sulfate contents (the evaporative-platform dolostones and the platform-margin shoal dolostones immediately underlying the evaporative facies). Early oil charge and limited intensity of TSR alteration, together with very low phyllosilicate content and early dolomitization, accounted for the preservation of anomalously high porosities in the reservoirs above the paleo-oil/water contact. A closed system seems to have played a special role in preserving the high porosity in the gas zone reservoirs below the paleo-oil/water contact. The closed system, which is unfavorable for deep burial carbonate dissolution and secondary porosity generation, was favorable for the preservation of early-formed porosity in deeply buried carbonates. Especially sucrosic and vuggy dolostones have a high potential to preserve such porosity.


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