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Enviroscan Ukrainian Institute of Speleology and Karstology


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Community news

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 tracer gaging is determining stream discharge by inserting a known quantity of dye and measuring its concentration after mixing [25]. consists of either the tracer-dilution method or the tracervelocity method (salt-velocity method). synonym: dye gaging.?

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 faults (Keyword) returned 214 results for the whole karstbase:
Showing 16 to 30 of 214
Notectonique dans le karst du N-O du lac de Thoune (Suisse), 1990,
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Jeannin, P. Y.
Neotectonic in the karst north of Lake Thoune (Switzerland) - The karstic area north of Lake Thoune is part of the "Border Chain" of the Swiss Alps (Cretaceous, Helvetic). It comprises large caves coming from two catchments. The first one pours out at the Beatushhle; more than 15 km of galleries are known in this area. The second one contains the Sieben Hengste - Hohgant - Hohlaub - Schrattenfluh region, it pours out at the Btterich and Gelberbrunnen springs, by Lake Thoune. It includes the very large "Sieben Hengste - Hohgant cave System" (length: 115 km; depth: 1050 m); the Brenschacht (length: >10 km; depth: 950 m), as well as several other important caves more than 1 km length. Recent shifts along faults were mainly measured in the Sieben Hengste Cave System. Neotectonic indication were of the following types: gallery sections displaced by the fault shifts, displaced pillar structures or shifted, inclined or broken speleothems. The fault movements were placed on a time scale according to the genetic evolution of the region. It indicates that there were three phases of movement, which greatly affected the underground flows and karstification. The geometric and dynamic analysis of the measured shifts and slikken-slides also indicates three phases of movements. The strain direction, causing these movements, was determined. Thus, three plio-quaternary tectonic phases were found: an alpine compressive SSE-NNW phase, followed by an extensive SSE-NNW phase and then again by a compressive one.

Sr isotope study of vein and cave calcites from southern Israel, 1990,
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Avigour A, Magaritz M, Issar A, Dodson Mh,
The strontium isotope compositions of secondary calcites from the Negev, southern Israel, were compared to those of the marine carbonate host rocks, which range in age from Triassic to Eocene, in order to understand fluid source and migration through fracture systems in dominantly carbonate strata. The Sr isotopes of these calcite clusters are divided into two groups: (1) calcites with 87Sr/86Sr values greater than those of the host carbonates; and (2) calcites with 87Sr/86Sr values close to the values of the host carbonate. 1. (1) These secondary calcites were found on the main tectonic lines of the Negev (faults and fold axes) and are enriched in 87Sr (87Sr/86Sr = 0.707709-0.709151) relative to the marine carbonate country rocks (87Sr/86Sr = 0.707251-0.70755, with one exception). These calcites are associated or crossed by thin veins filled by Fe- and Mn-oxides.2. (2) Secondary calcites with 87Sr/86Sr values close to those of the marine carbonate country rocks (0.7073-0.7077) are found in karstic caves and veins, and are located in sites which are not on the major faults and fold axes. These calcites are not crossed by Fe- and Mn-oxides.The isotopic results indicate that the solutions from which the secondary minerals of the first group precipitated were not in isotopic equilibrium with the marine host rocks. The possible source of the precipitating solutions can be either surface rain descending through the fault system or ascending groundwaters from the deep Nubian aquifer (Paleozoic to Early Cretaceous in age). In both cases there would be a limited interaction with the host sandstone rock which usually is depleted in Sr. The similarity of the 87Sr/86Sr values to those of the host rocks in the second group suggests that the main source of Sr in these calcite crystals was from the dissolution of the marine carbonate country rocks by rain- and flood waters

POST JURASSIC BRITTLE TECTONICS OF THE HAMMAM ZRIBA MINE (NORTHEASTERN TUNISIA) AND RELATED KARST AND FLUORINE, BARYTINE AND CELESTITE OCCURRENCES IN CARBONATE ENVIRONMENTS, 1991,
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Melki F. , Zargouni F. ,
The Hammam Zriba mine is located in a lenticular horst structure, of varying width (0.3 to 1 km) and NNW-SSE strike over about 3 kms. The mineralization is strata-bound at the top of massive Portlandian limestones and is overlain by embedded Middle to Upper Campanian limestones with marl intercalations. This horst has formed during the late Jurassic as an emerged block bound by major faults that were remobilized later during various deformation stages. These facts are clearly documented by field observations and tectonic analysis essentially along the N160-N180 trending faults in the Portlandian lithofacies. These fractures have also controlled the palaeomorphological framework of the uppermost part of the Portlandian massive facies. The overlying Campanian unit exhibits onlap structures that rest on the irregular eroded karstified and mineralized surface which forms a screen surface for the upward channelized fluids and mineral formations in karst and graben. Fluids were apparently channelized by faults trending N070-N090 and N160-180, a few hundred metres long, that have facilitated karst, dissolution and mineral deposition during tectonic events

DIAGENESIS AND MINERALIZATION PROCESSES IN DEVONIAN CARBONATE ROCKS OF THE SIDING-GUDAN LEAD-ZINC MINERAL SUBDISTRICT, GUANGXI, SOUTHWEST CHINA, 1991,
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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

GENERAL CENOZOIC EVOLUTION OF THE MALDIVES CARBONATE SYSTEM (EQUATORIAL INDIAN-OCEAN), 1992,
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Aubert O, Droxler Aw,
Analyses and interpretation of an industrial multi-channel seismic grid, a 2.3 km-deep industrial well (NMA-1) and two ODP (Sites 715 and 716), have generated new insights into the evolution of the Maldives carbonate system, Equatorial Indian Ocean. The present physiography of the Maldives Archipelago, a double chain of atolls delineating an internal basin, corresponds only to the latest phase of a long and dynamic evolution, far more complex than the simple vertical build-up of reef caps on top of thermally subsiding volcanic edifices. Through the Cenozoic evolution of the Maldives carbonate system, distinct phases of vertical growth (aggradation), exposure, regional or local drowning, and recovery of the shallow banks by lateral growth (progradation) have been recognized. The volcanic basement underlying the Maldives Archipelago is interpreted to be part of a volcanic ridge generated by the northern drift of the Indian plate on top of the hotspot of the island of Reunion. The volcanic basement recovered at well NMA-1 and ODP Site 715 has been radiometrically dated as 57.2 1.8 Ma (late Paleocene) by 40Ar-39Ar. Seismic and magnetic data indicate that this volcanic basement has been affected by a series of NNE-SSW trending subvertical faults, possibly associated with an early Eocene strike-slip motion along an old transform zone. The structural topography of the volcanic basement apprears to have dictated the initial geometry of the Eocene and early Oligocene Maldives carbonate system. Biostratigraphic analyses of samples, recovered by drilling in Site 715 and exploration well NMA-1, show that the Maldives shallow carbonate system was initiated during the early Eocene on top of what were originally subaerial volcanic edifices. The Eocene shallow carbonate sequence, directly overlying the volcanic basement at NMA-1, is dolomitized and remains neritic in nature, suggesting low subsidence rates until the early Oligocene. During this first phase of the Maldives carbonate system evolution, shallow carbonate facies aggraded on top of basement highs and thick deep-water periplatform sediments were deposited in some central seaways, precursors of the current wider internal basins. In the middle Oligocene, a plate reorganization of the equatorial Indian Ocean resulted in the segmentation of the hotspot trace and the spreading of the Maldives away from the transform zone. This plate reorganization resulted in increasing subsidence rates at NMA-1, interpreted to be associated with thermal cooling of the volcanic basement underlying the Maldives carbonate system. This middle Oligocene event also coincides with a regional irregular topographic surface, considered to represent a karst surface produced by a major low-stand. Deep-water carbonate facies, as seen in cuttings from NMA-1, overlie the shallow-water facies beneath the karst surface which can, therefore, be interpreted as a drowning unconformity. In the late Oligocene, following this regional deepening event, one single central basin developed, wider than its Eocene counterparts, and the current intraplatform basin was established. Since the early to middle Miocene, the shallow carbonate facies underwent a stage of local recovery by progradation of neritic environments towards the central basin. The simultaneous onset in the early middle Miocene of the monsoonal wind regime may explain the development of bidirectional slope progradations in the Maldives. During the late Miocene and the early Pliocene, several carbonate banks were locally drowned, whereas others (i.e. Male atoll) display well-developed lateral growth through margin progradations during the same interval. Differential carbonate productivity among the atolls could explain these diverse bank responses. High-frequency glacialeustatic sea-level fluctuations in the late Pliocene and Pleistocene resulted in periodic intervals of bank exposure and flooding, and developed the present-day physiography of atolls, with numerous faros along their rims and within their lagoons

STRUCTURAL AND HYDROGEOLOGICAL ORIGIN OF TOWER KARST IN SOUTHERN CHINA (LIJIANG PLAIN IN THE GUILIN REGION), 1992,
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Drogue C, Bidaux P,
Spectacular towers (average 130 m high) are to be seen in the Lijiang plain near Guilin in middle and upper Devonian limestone forming a downthrown structural panel surrounded by the high relief of a cockpit karst. The limestone was fractured by at least three Triassic and Tertiary tectonic episodes. Statistical analysis of the altitudes of tower summits shows that they are distributed according to a log-normal law with a well marked mode at 250-280 m. This mode is very similar to that of the depression altitudes of the cockpit karst. It was deduced that tower summits and cockpit bottoms show that there was an ancient, relatively flat surface which was the basic level for flow in the surrounding karstic relief (water table at ground level). Fall in this ground water caused preferential karstic breakdown in very fractured zones, leaving the stronger blocks. This subsidence must have taken place in stages, as is shown by Pliocene and lower Quaternary fossil cavities at various altitudes of the towers. Observation of fracturing in the field, in aerial photographs and satellite images show that the edges of the towers are mainly transverse faults with sub-vertical planes

POLYGENETIC ORIGIN OF HRAD-VALLIS REGION OF MARS, 1992,
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Dehon Ra,
Hrad Vallis is located in the transition zone between Elysium Mons and Utopia Planitia. Near its origin, at the northern edge of Elysium lavas, Hrad Vallis is characterized by a low-sinuousity channel within a north-northwest-trending, broad, flat-floored valley. A nearby flat-floored valley is parallel to the Hrad trend and parallel to elongate depressions, fissures, and faults in the region. An apparent hierarchy of landforms provides insight into the origin of the features associated with Hrad Vallis. The sequence leading to the development of Hrad Vallis consists of the following (1) formation of isolated depressions as either karst depressions or thermokarst valleys along faults and fissures in response to circulating ground water; (2) expansion of depressions along structural trends to coalesce as composite valleys, and (3) incision of a channel on the floor of Hrad valley by continued discharge of water from the subsurface after its initial formation by nonfluvial processes. Mud flows, polygonally fractured terrain, and chaotic terrain near the head of the major valleys suggest thixotropic behavior of saturated, clay-rich materials. An extended period of time is indicated during which freely circulating water existed on id beneath the surface of Mars. Karst and thermokarst processes imply very different climatic regimes and different host materials. The presence of karst topography implies extensive deposition of carbonates or other soluble rocks, whereas the presence of thermokarst basins implies the existence of porous, water/ice-saturated clastic or volcaniclastic materials

Le palokarst littoral de Provence (Estaque, Calanques et zone de Bandol), 1993,
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Blanc, J. J.
The general features of coastal paleokarst in Provence are describes: suspended gallery sections and drain-pipes cut across by fracturations or fault reactivation. The types of deformations and breaking observed are tilting, stalactite fall, extension fault sealing, reactivation and speleothem shearing, coastal wall and karstic cleft collapse as well as network deformation. The influence of structural environment is represented by overlapping strata, coastal faults and crossed-fault systems. Emphasis has been laid on the tectonic inheritance as well as the geodynamic context. To conclude, the importance of provenal-ligurian rifting mechanisms and the transition to faulted and distorted margin is underlined.

CHEMICAL-REACTION PATH MODELING OF ORE DEPOSITION IN MISSISSIPPI VALLEY-TYPE PB-ZN DEPOSITS OF THE OZARK REGION UNITED-STATES MIDCONTINENT, 1994,
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Plumlee G. S. , Leach D. L. , Hofstra A. H. , Landis G. P. , Rowan E. L. , Viets J. G. ,
The Ozark region of the U.S. midcontinent is host to a number of Mississippi Valley-type districts, including the world-class Viburnum Trend, Old Lead Belt, and Tri-State districts and the smaller Southeast Missouri barite, Northern Arkansas, and Central Missouri districts. There is increasing evidence that the Ozark Mississippi Valley-type districts formed locally within a large, interconnected hydrothermal system that also produced broad fringing areas of trace mineralization, extensive subtle hydrothermal alteration, broad thermal anomalies, and regional deposition of hydrothermal dolomite cement. The fluid drive was provided by gravity flow accompanying uplift of foreland thrust belts during the Late Pennsylvanian to Early Permian Ouachita orogeny. In this study, we use chemical speciation and reaction path calculations, based on quantitative chemical analyses of fluid inclusions, to constrain likely hydrothermal brine compositions and to determine which precipitation mechanisms are consistent with the hydrothermal mineral assemblages observed regionally and locally within each Mississippi Valley-type district in the Ozark region. Deposition of the regional hydrothermal dolomite cement with trace sulfides likely occurred in response to near-isothermal effervescence of CO2 from basinal brines as they migrated to shallower crustal levels and lower confining pressures. In contrast, our calculations indicate that no one depositional process can reproduce the mineral assemblages and proportions of minerals observed in each Ozark ore district; rather, individual districts require specific depositional mechanisms that reflect the local host-rock composition, structural setting, and hydrology. Both the Northern Arkansas and Tri-State districts are localized by normal faults that likely allowed brines to rise from deeper Cambrian-Ordovician dolostone aquifers into shallower carbonate sequences dominated by limestones. In the Northern Arkansas district, jasperoid preferentially replaced limestones in the mixed dolostone-limestone sedimentary packages. Modeling results indicate that the ore and alteration assemblages in the Tri-State and Northern Arkansas districts resulted from the flow of initially dolomite-saturated brines into cooler limestones. Adjacent to fluid conduits where water/rock ratios were the highest, the limestone was replaced by dolomite. As the fluids moved outward into cooler limestone, jasperoid and sulfide replaced limestone. Isothermal boiling of the ore fluids may have produced open-space filling of hydrothermal dolomite with minor sulfides in breccia and fault zones. Local mixing of the regional brine with locally derived sulfur undoubtedly played a role in the development of sulfide-rich ore runs. Sulfide ores of the Central Missouri district are largely open-space filling of sphalerite plus minor galena in dolostone karst features localized along a broad anticline. Hydrothermal solution collapse during ore deposition was a minor process, indicating dolomite was slightly undersaturated during ore deposition. No silicification and only minor hydrothermal dolomite is present in the ore deposits. The reaction path that best explains the features of the Central Missouri sulfide deposits is the near-isothermal mixing of two dolomite-saturated fluids with different H2S and metal contents. Paleokarst features may have allowed the regional brine to rise stratigraphically and mix with locally derived, H2S-rich fluids

SEDIMENT-HOSTED GOLD MINERALIZATION IN THE RATATOTOK DISTRICT, NORTH SULAWESI, INDONESIA, 1994,
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Turner S. J. , Flindell P. A. , Hendri D. , Hardjana I. , Lauricella P. F. , Lindsay R. P. , Marpaung B. , White G. P. ,
The Ratatotok district in the Minahasa Regency of North Sulawesi, Indonesia is an area of significant gold mineralisation. Gold has been mined in the district since at least the 1850s, and intensively by the Dutch between 1900 and 1921 with a recorded production of 5,060 kg of gold. Newmont began exploring the district in 1986, and has delineated a major sediment-hosted replacement-style deposit at Mesel, and other smaller deposits in an 8 X 5 km area. A total drill-indicated resource of over 60 metric tonnes of gold ( 2 Moz) is reported for Mesel, and three of the smaller deposits. Approximately 80% of this resource is refractory. Silver grades are usually low (< 10 g/t). The Mesel deposit is similar to many Carlin-type deposits in carbonate hostrocks, alteration, geochemical signature and ore mineralogy, but is distinct in tectonic setting. The discovery of replacement-style mineralisation at Mesel, in an impure limestone within a Tertiary island arc environment, demonstrates that deposits with outward characteristics similar to Carlin-type mineralisation are not restricted to a continental setting. Carbonate sediments in the Ratatotok district were deposited in a Late Miocene restricted basin. Later compressional tectonics caused uplift that resulted in karst development in the limestone and erosion of the adjacent volcanic arc with deposition of a thick epiclastic unit. This was followed by intrusion of shallow level pre-mineral andesite into the sequence. Mineralisation at Mesel, and probably elsewhere in the district, is synchronous with the late-stage reactivation of strike-slip faults. Mineralising fluids at Mesel were focussed along steep structures sympathetic to these faults, and trapped below a relatively impermeable andesite cap rock. Hydrothermal fluids caused decalcification of the silty, more permeable carbonate units with the formation of secondary dolomite, deposition of fine arsenian pyrite, silica veinlets and gold. Volume loss due to decalcification and dolomite formation caused collapse brecciation which enhanced fluid flow and further mineralisation. This locally culminated in total decarbonation and deposition of massive silica. Late-stage stibnite occurs in structural zones within the ore deposit, whereas arsenic (as realgar and orpiment) and mercury (as cinnabar) are concentrated on the periphery. Elsewhere in the Ratatotok district, gold mineralisation is restricted to replacement-style mineralisation in permeable zones along limestone-andesite contacts, open-space-filling quartz-calcite veins and stockworks, and residual quartz-clay breccias. The residual breccias are developed in-situ, and are interpreted to form by dissolution of the wallrock limestone from around pre-existing mineralisation. This has resulted in widespread eluvial gold occurrences

Tectonic Speleogenesis of Devils Hole, Nevada, and Implications for Hydrogeology and the Development of Long, Continuous Paleoenvironmental Records, 1994,
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Riggs Alan C. , Carr W. J. , Kolesar Peter T. , Hoffman Ray J. ,
Devils Hole, in southern Nevada, is a surface collapse into a deep, planar, steeply dipping fault-controlled fissure in Cambrian limestone and dolostone. The collapse intersects the water table about 15 m below land surface and the fissure extends at least 130 m deeper. Below water, most of the fissure is lined with a >30-cm-thick layer of dense maxillary calcite that precipitated continuously from groundwater for >500,000 yr. The thick mammillary calcite coat implies a long history of calcite-supersaturated groundwaters, which, combined with the absence of dissolutional morphologies, suggests that Devils Hole was not formed by karst processes. Devils Hole is located in a region of active extension; its tectonic origin is shown by evidence of spreading of its planar opening along a fault and by the orientation of its opening and others nearby, perpendicular to the northwest-southeast minimum principal stress direction of the region. Most Quaternary tectonic activity in the area, including seismicity and Quaternary faults and fractures, occurs on or parallel to northeast-striking structures. The hydrogeologic implications of this primarily structural origin are that fracture networks and caves opened by extensional tectonism can act as groundwater flowpaths functionally similar to those developed by karst processes and that, during active extension, transmissivity can be maintained despite infilling by mineral precipitation. Such extensional environments can provide conditions favorable for accumulation of deposits preserving long, continuous paleoenvironmental records. The precipitates in Devils Hole store chronologies of flow system water-level fluctuations, hydrochemistry, a half-million-yr proxy paleoclimate record, evidence of Devils Hole's tectonic origin, and probably atmospheric circulation

Synsedimentary collapse of portions of the lower Blomidon Formation (Late Triassic), Fundy rift basin, Nova Scotia, 1995,
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Ackermann Rv, Schlische Pw, Olsen Pe,
A chaotic mudstone unit within the lower Blomidon Formation (Late Triassic) has been traced for 35 km in the Mesozoic Fundy rift basin of Nova Scotia. This unit is characterized by highly disrupted bedding that is commonly cut by small (<0.5 m) domino-style synsedimentary normal faults, downward movement of material, geopetal structures, variable thickness, and an irregular, partially faulted contact with the overlying unit. The chaotic unit is locally overlain by a fluvial sandstone, which is overlain conformably by mudstone. Although the thickness of the sandstone is highly variable, the overlying mudstone unit exhibits only gentle regional dip. The sandstone unit exhibits numerous soft-sediment deformation features, including dewatering structures, convoluted bedding, kink bands, and convergent fault fans. The frequency and intensity of these features increase dramatically above low points at the base of the sandstone unit. These stratigraphic relations suggest buried interstratal karst, the subsurface dissolution of evaporites bounded by insoluble sediments. We infer that the chaotic unit was formed by subsidence and collapse resulting from the dissolution of an evaporite bed or evaporite-rich unit by groundwater, producing dewatering and synsedimentary deformation structures in the overlying sandstone unit, which infilled surface depressions resulting from collapse. In coeval Moroccan rift basins, facies similar to the Blomidon Formation are associated with halite and gypsum beds. The regional extent of the chaotic unit indicates a marked period of desiccation of a playa lake of the appropriate water chemistry. The sedimentary features described here may be useful for inferring the former existence of evaporites or evaporite-rich units in predominantly elastic terrestrial environments

Ring of cenotes (sinkholes), Northwest Yucatan, Mexico; its hydrogeologic characteristics and possible association with the Chicxulub impact crater, 1995,
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Perry Eugene, Marin Luis E. , Mcclain Jana, Velazquez Guadalupe,
A 180-km-diameter semicircular band of abundant karst sinkholes (Ring of Cenotes) in Northwest Yucatan, Mexico, coincides approximately with a concentric ring of the buried Chicxulub structure, a circular feature manifested in Cretaceous and older rocks, that has been identified as the product of the impact of a bolide. The ring, expressed in Tertiary rocks, marks a zone of high permeability as shown by (1) the sinkholes themselves, (2) breaks in the coastal dune system and high density of springs where the ring intersects the coast, and (3) water-level transects characterized by a decline in water level toward the ring. Any direct relation that exists between the Ring of Cenotes and the Chicxulub structure bears on regional hydrogeology. If the layer or zone responsible for the ring is deeply buried, it may act as a barrier to the movement of ground water across the main flow direction. Shallower zones of horizontal permeability could result in less complete diversion of ground water. Through its influence on Yucatan aquifer characteristics, the ring may provide a link between modern environmental problems and astrogeology. Possible origins for the Ring of Cenotes are (1) faulting, perhaps reactivated by post-Eocene-mid-Miocene basin loading, (2) permeability in a buried reef complex developed in the shallow Paleocene sea around the crater rim, or (3) breccia collapse occasioned by consolidation or by solution of evaporite components. If the ring developed on ancient faults, it may outline hydrothermal systems and mineral deposits produced during Paleocene cooling of the Chicxulub melt sheet

REMOTE-SENSING OF TECTONIC FABRIC CONTROLLING GROUNDWATER-FLOW IN DINARIC KARST, 1995,
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Kresic N. ,
Geological and hydrogeological remote sensing techniques can be applied very favorably to Dinaric karst in the Balkans, a well-known reference area for studies of karst phenomena. The elements that make karst terrain of the Dinarides suitable for remote sensing are geomorphologic characteristics, in particular the specific surface drainage and karst forms, the varying vegetation that most often reflects the existence of different geologic formations on the surface, and distinct tectonic features. Some of the world's largest springs, ponors (sinks), and dolines are controlled by fractures visible on both satellite images and aerial photographs. Lineaments represent fault zones, systems of close faults with similar strike, or large individual faults which all are young or show recently renewed activity. Their neotectonic character and major importance for karst groundwater flow are confirmed by numerous field investigations including water tracing, geophysical research, and drilling

Prhistoire et karst littoral : la grotte Cosquer et les calanques mar_seillaises (Bouches-du-Rhne, France), 1996,
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Collinagirard, J.
The Cosquer Cave is a French palaeolithic painted and engraved cave (27000/ 18500 BP) which is located under the sea, in the urgonian limestones of Cap Morgiou ("Massif des Calanques"; Marseille). The en trance was submerged at the end of the last glacial stage and is presently 37 m under sea level. A synthesis about the Cosquer cave environmental studies is presented here. Structural studies show that cave planimetry is determined by Cap Morgiou fracturations (mainly NW/SE and N/S vertical faults). Through archaeological studies, a concretion breaking period can be dated between 27000 and 18000 BP. Geomorphological study of the continental shelf at the foot of the Cosquer cave area shows fossils shorelines at -36 m, -50/55 m, -90 m, -100 m depth. Radiocarbon datings from shells collected in 100m sediments yielded a date of 13 250 BP. Direct scuba diving observations and submarine clive profiles sketching show several eustatic stand-still levels between -36 m and the sea surface indicating a probable tectonic stability during the last 10000 years.

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