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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 roof drainage is precipitation runoff from roofs.?

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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 oligocene (Keyword) returned 59 results for the whole karstbase:
Showing 46 to 59 of 59
Sedimentary manganese metallogenesis in response to the evolution of the Earth system, 2006, Roy Supriya,
The concentration of manganese in solution and its precipitation in inorganic systems are primarily redox-controlled, guided by several Earth processes most of which were tectonically induced. The Early Archean atmosphere-hydrosphere system was extremely O2-deficient. Thus, the very high mantle heat flux producing superplumes, severe outgassing and high-temperature hydrothermal activity introduced substantial Mn2 in anoxic oceans but prevented its precipitation. During the Late Archean, centered at ca. 2.75[no-break space]Ga, the introduction of Photosystem II and decrease of the oxygen sinks led to a limited buildup of surface O2-content locally, initiating modest deposition of manganese in shallow basin-margin oxygenated niches (e.g., deposits in India and Brazil). Rapid burial of organic matter, decline of reduced gases from a progressively oxygenated mantle and a net increase in photosynthetic oxygen marked the Archean-Proterozoic transition. Concurrently, a massive drawdown of atmospheric CO2 owing to increased weathering rates on the tectonically expanded freeboard of the assembled supercontinents caused Paleoproterozoic glaciations (2.45-2.22[no-break space]Ga). The spectacular sedimentary manganese deposits (at ca. 2.4[no-break space]Ga) of Transvaal Supergroup, South Africa, were formed by oxidation of hydrothermally derived Mn2 transferred from a stratified ocean to the continental shelf by transgression. Episodes of increased burial rate of organic matter during ca. 2.4 and 2.06[no-break space]Ga are correlatable to ocean stratification and further rise of oxygen in the atmosphere. Black shale-hosted Mn carbonate deposits in the Birimian sequence (ca. 2.3-2.0[no-break space]Ga), West Africa, its equivalents in South America and those in the Francevillian sequence (ca. 2.2-2.1[no-break space]Ga), Gabon are correlatable to this period. Tectonically forced doming-up, attenuation and substantial increase in freeboard areas prompted increased silicate weathering and atmospheric CO2 drawdown causing glaciation on the Neoproterozoic Rodinia supercontinent. Tectonic rifting and mantle outgassing led to deglaciation. Dissolved Mn2 and Fe2 concentrated earlier in highly saline stagnant seawater below the ice cover were exported to shallow shelves by transgression during deglaciation. During the Sturtian glacial-interglacial event (ca. 750-700[no-break space]Ma), interstratified Mn oxide and BIF deposits of Damara sequence, Namibia, was formed. The Varangian ([identical to] Marinoan; ca. 600[no-break space]Ma) cryogenic event produced Mn oxide and BIF deposits at Urucum, Jacadigo Group, Brazil. The Datangpo interglacial sequence, South China (Liantuo-Nantuo [identical to] Varangian event) contains black shale-hosted Mn carbonate deposits. The Early Paleozoic witnessed several glacioeustatic sea level changes producing small Mn carbonate deposits of Tiantaishan (Early Cambrian) and Taojiang (Mid-Ordovician) in black shale sequences, China, and the major Mn oxide-carbonate deposits of Karadzhal-type, Central Kazakhstan (Late Devonian). The Mesozoic period of intense plate movements and volcanism produced greenhouse climate and stratified oceans. During the Early Jurassic OAE, organic-rich sediments host many Mn carbonate deposits in Europe (e.g., Urkut, Hungary) in black shale sequences. The Late Jurassic giant Mn Carbonate deposit at Molango, Mexico, was also genetically related to sea level change. Mn carbonates were always derived from Mn oxyhydroxides during early diagenesis. Large Mn oxide deposits of Cretaceous age at Groote Eylandt, Australia and Imini-Tasdremt, Morocco, were also formed during transgression-regression in greenhouse climate. The Early Oligocene giant Mn oxide-carbonate deposit of Chiatura (Georgia) and Nikopol (Ukraine) were developed in a similar situation. Thereafter, manganese sedimentation was entirely shifted to the deep seafloor and since ca. 15[no-break space]Ma B.P. was climatically controlled (glaciation-deglaciation) assisted by oxygenated polar bottom currents (AABW, NADW). The changes in climate and the sea level were mainly tectonically forced

Growth, Demise, and Dolomitization of Miocene Carbonate Platforms on the Marion Plateau, Offshore NE Australia, 2006, Ehrenberg Sn, Mcarthur Jm, Thirlwall Mf,
Strontium-isotope stratigraphy has been used to examine the timing of depositional events and dolomitization in two Miocene carbonate platforms cored by Ocean Drilling Program (ODP) Leg 194, just seaward of the Great Barrier Reef. The results provide firm constraints for correlating surfaces and depositional stages between the two platforms and thereby relating seismic sequences previously defined in the off-platform sediments to the lithostratigraphic units described from cores in the seismically transparent platform-top sites. Oyster-bearing beds at the base of both platform successions yield early Oligocene ages (29-31 Ma), thus dating initial transgression of the Marion Plateau's volcanic basement. There followed a period of slow accumulation of shallow-water grainstones rich in quartz and phosphate grains in late Oligocene time (29-23 Ma; seismic Megasequence A). The main growth of the carbonate platforms took place in early to late Miocene time (23-7 Ma), comprising five depositional sequences. The first four of these (seismic Megasequence B) are common to both platforms and terminated with a possible karst surface at 10.7 Ma. Different sedimentologic expression of this megasequence in the two platforms reflects contrasting progradational versus aggradational geometries in the locations studied. The final growth stage (seismic Megasequence C) occurred only in the southern platform and terminated at 6.9 Ma. Both platform-demise events (10.7 and 6.9 Ma) approximately coincide with falls in global sea level combined with longer-term trends of decreasing water temperature. Sr-isotope ages of dolostones increase with depositional age, and older dolostones in the southern platform have more coarsely crystalline and fabric-destructive textures than overlying younger dolostones. These relationships are consistent with dolomitization by normal seawater shortly after deposition and overprinting of multiple times of dolomite recrystallization and cementation in the deeper strata

Aroca (domaine marin ctier, Pays basque, France) : un karst continental ennoy par les transgressions maritimes quaternaires, 2007, Vanara Nathalie , Perre Alain, Pernet Marc, Latapie Serge, Jaillet Stphane, Martine Olivier
AROCA (LITTORAL, BASQUE COUNTRY, FRANCE): A CONTINENTAL KARST DROWNED BY QUATERNARY MARITIME TRANSGRESSIONS. The rocky formations in shallow areas of the Atlantic coast are hardly known. Studies are rare because of the difficulties of direct observation (diving in always agitated, troubled water, depth between 20 and 40 m). Our first step was to make a detailed topography of a submarine plateau named Aroca, 4 km off Socoa harbour (bay of Saint-Jean-de-Luz). This plateau was already known for having a large variety of forms within a small surface (150 x 100 m). We gave names to most remarquable formations and defined five main characteristic zones: - in the exokarstic domain 1/ a top surface with channels, 2/ a dismantled surface with pinnacles; - in the endokarstic domain 3/ caves, galleries, arches; - at the limits 4/ three inclined plans, west, north and east, 5/ a cliff to the south. A typology of forms shows a predominance of ablation reliefs: aplanation, over-deepened channels, covered rooms and galleries, arches, residual pinnacles. Deposit accumulations regroup chaotic breakdown blocks, pebble accumulations and sand covers. Statement of explanations requires recognition of the nature and age of the outcrops and succession of erosional agents during the Pleistocene. Rocks are dated from Ypresien (limestones) to Bartonian (marls). Continental erosion during sea regressions is responsible of caracteristic landforms and deposits; for example wall banks, allochthonous pebbles The currently active marine erosion during sea transgressions is due to storms, tide, dissolution, biochemical action (lithophages) and gravity. We propose a paleogeographic reconstitution. After an essentially calcareous sedimentation in Eocene and an essentially marly sedimentation in Oligocene, the sea recedes during Miocene. From then, the platform, henceforward above the water, is subject to meteoric erosion. In Pliocene, evolution of the massif is isovolumic (under a marly cover and with a low hydraulic gradient). During the lower and middle Pleistocene, the erosion of the marly cover goes on. During the upper Pleistocene, the wurmian (18000 BP) marine regression allows entrenchment of the hydrographic system thanks to an increase of hydraulic gradients (classic functional karst). From 15000 years onwards, a general transgression of sea level happens by successive steps. During the Boreal, a break in transgression allows the formation of a paleo-shore at 20 to 30 m, inducing a peneplanation phase in the tidal or infratidal zone. From 7500 BP onwards, a a rapid transgression from 23 to 8, then a slower one from 8 to the present level stops karstification on the massif. At present, only marine abrasion is active and tends to obliterate the previously built landforms.

Early late Pliocene paleokarstic fillings predating the major Plio-Pleistocene erosion of the Quercy table, SW-France, 2007, Aguilar J. P. , Michaux J. , Pé, Lissié, T. , Sigé, B.

This evolution consists, first in the elaboration of the underground net systems, then in a long polyphased process of filling – emptying the karstic voids, according to the up and down base level changes that occurred almost continuously during the first half of the Tertiary era. The filling sediments are mostly vadose clay deposits, the various ages of which being established from the study of their fossil vertebrate contents (for latest accounts see Pélissié & Sigé 2006). Then, since latest Oligocene times, the Quercy platform was covered with prograding lacustrine sediments of the Aquitaine Basin. Finally, the whole structure was strongly worn down by the so- called Plio-Pleistocene erosional phase: the previously deep underground system became closer to the surface, and was exposed both to erosion and widening, but also Plio-Pleistocene fillings occurred as shown by the fossils they include (Crochet et al. 2006). Among the latter are rare Late Pliocene and Plio-Pleistocene tooth specimens.


Palaeomagnetism and Magnetostratigraphy of Karst Sediments in Slovenia, 2008, Zupan Hajna Nadja, Mihevc Andrej, Pruner Petr, Bosk Pavel

Results of more than 10 years intensive study of palaeomagnetic properties and magnetostratigraphy of karst sediments in Slovenia are summarized. The research covered the most important karst regions, from lowlands to high mountains. It included both well-known and documented sites, and relatively unknown or newly found locations in caves and surface karst sediments. The territory of Slovenia, with its numerous karst regions, long history of karst evolution and relatively good knowledge of the karst sediments represents an ideal testing ground for comprehensive research on individual infilling processes, their stages and periods. The questions concentrated to the time span of karst evolution in Slovenia, age of karst surfaces, speleogenesis and rates of processes. The majority of karst sediment dating has been carried out in south-western Slovenia (in the north-western part of the Dinaric Karst, which is known as the Kras) where Eocene flysch is the last marine deposit preserved in the geologic record. The Oligocene to Quaternary period represented mostly terrestrial phase with prevailing surface denudation and erosion processes. Therefore only karst sediments preserved on karst surface and in subsurface can yield some facts and ideas of karst evolution and its age. In the book 21 locations are described, 19 from Slovenia and two Italian Karst. Each location is placed in space describing geological, karstological and speleological properties. A precise description of studied sediment profile with lithological and mineralogical composition follows obtained by various research methods. Every profile contains also the palaeomagnetic results with magnetostratigraphic and palaeomagnetic properties.

Dating of cave sediments by the application of the palaeomagnetic method is a difficult and sometimes risky task, as the method is comparative in its principles and does not provide numerical ages. Repeated sampling in some profiles have shown that only dense sampling (high-resolution approach with sampling distance of 2?4 cm), can ensure reliable results. Correlation of the magnetostratigraphic results we obtained, and the interpretations tentatively placed upon them has shown that in the majority of cases, application of an additional dating method is needed to either reinforce the palaeomagnetic data or to help to match them with the geomagnetic polarity timescale.

The most important result is the discovery that cave fills have substantially older ages than generally expected earlier (max. about 350 ka). Palaeomagnetic data in combination with other dating methods, especially biostratigraphy, have shifted the possible beginning not only of the speleogenesis but also of the cave filling processes in Slovenia far below the Tertiary/Quaternary boundary. Results suggest that there were probably some distinct phases of massive deposition in caves. The oldest one took place from about 1.8 to more than 5.4 Ma (with two phases at 1.8 ? 3.6 and about 4.1 ? 5.4 Ma). The data support and better define the estimated ages of the surface and cave sediments that were based on geomorphic evidences, especially from unroofed caves.

The evolution of the caves took part within one karstification period, which began with the regression of Eocene sea and exposing of limestones at the surface within complicated overthrusted structure, which formed principally during Oligocene to early Miocene.


Fluid flow reconstruction in karstified Panormide platform limestones (north-central Sicily): Implications for hydrocarbon prospectivity in the Sicilian fold and thrust belt, 2010, Dewever B. , Berwouts I. , Swennen R. , Breesch L. , Ellam R. M.

Diagenetic analysis based on field and petrographic observations, isotope and microthermometric data was used to reconstruct the fluid flow history of the Cretaceous shallow water limestones from the Panormide platform exposed in north-central Sicily. Analysis focused on diagenetic products in cavities and dissolution enlarged fractures of the karstified limestones that occur just below a regional unconformity. The fluid flow history could be broken down into five stages that were linked to the kinematic and burial history of the region. (1) Petrography (zoned cathodoluminescence and speleothem textures) and stable isotopes (6.5 PDB &/Tm_2 to _5 _C), but at increasingly higher temperatures (Th 60–120 _C). This has been interpreted as precipitation during Oligocene foredeep burial. (4) Hot (Th 130–180 _C), low saline (Tm he low salinity and relatively high d18OSMOW signatures of the fluids are interpreted to be the result of clay dewatering reactions. The presence of bitumen and associated fluorite with hydrocarbon inclusions at this stage in the paragenesis constrains the timing of oil migration in the region. (5) Finally, high saline fluids with elevated 87Sr/86Sr (0.7095–0.7105) signatures invaded the karst system. This last fluid flow event was possibly coeval with localized dolomitization and calcite cementation along high-angle faults of Pliocene age, as suggested by identical radiogenic signatures of these diagenetic products.


Mineralogy of Iza Cave (Rodnei Mountains, N. Romania), 2011, Tă, Maş, Tudor, Kristly Ferenc, Barbutudoran Lucian

The secondary minerals from Iza Cave result from the interactions of karst water and/or cave atmosphere over a variety of sedimentary and metamorphic rocks. The cave passages expose at various extents Eocene limestones and conglomerates, Oligocene black shales, Upper Precambrian micaschists, marble and dolomitic marble and associated ore deposits.
Twelve secondary minerals identified in the cave (carbonates, sulfates, phosphates, oxides and hydroxides, and silicates) are presented in this study. Calcite, aragonite, gypsum, brushite and hydroxylapatite are the components of common speleothems in the limestone, dolomite and conglomerate areas of the cave. Ankerite crusts are related to areas with pyrite mineralization within the metamorphic carbonate rocks. Goethite, jarosite, hematite and gypsum form various speleothems in the sectors within micaschists and conglomerates. Large weathering deposits occurring in passage areas developed within micaschists consist of illite, kaolinite, jarosite, goethite, gypsum and alunite. The extent of the weathering deposits occurring on non-karst rocks in the underground environment makes this cave a particularly interesting site for studies of water-rock interactions.


Geochemical/isotopic evolution of Pb-Zn deposits in the Central and Eastern Taurides, Turkey, 2011, Hanilci N. , Ozturk H.

The Central and Eastern Taurides contain numerous carbonate-hosted Pb-Zn deposits, mainly in Devonian and Permian dolomitized reefal-stramatolitic limestones, and in massive Jurassic limestones. We present and compare new fluid inclusion and isotopic data from these ore deposits, and propose for the first time a Mississippi Valley-type (MVT) mode of origin for them. Fluid inclusion studies reveal that the ore fluids were highly saline (13-26% NaCl equiv.), chloride-rich (CaCl2) brines, and have average homogenization temperatures of 112°C, 174.5°C, and 211°C for the Celal Dag, Delikkaya, and Ayrakl deposits, respectively. Furthermore, the ?34S values of carbonate-hosted Pb-Zn deposits in the Central and Eastern Taurides vary between -5.4‰ and +13.70‰. This indicates a possible source of sulphur from both organic compounds and crustal materials. In contrast, stable sulphur isotope data (average ?34S -0.15‰) for the Cadrkaya deposit, which is related to a late Eocene-Oligocene (?) granodioritic intrusion, indicates a magmatic source. The lead isotope ratios of galena for all investigated deposits are heterogeneous. In particular, with the exception of the Sucat district, all deposits in the Eastern (Delikkaya, Ayrakl, Denizovas, Cadrkaya) and Central (Katranbasi, Kucuksu) Taurides have high radiogenic lead isotope values (206Pb/204Pb between 19.058 and 18.622; 207Pb/204Pb between 16.058 and 15.568; and 208Pb/204Pb between 39.869 and 38.748), typical of the upper continental crust and orogenic belts. Fluid inclusion, stable sulphur, and radiogenic lead isotope studies indicate that carbonate-hosted metal deposits in the Eastern (except for the Cadrkaya deposit) and the Central Taurides are similar to MVT Pb-Zn deposits described elsewhere. The primary MVT deposits are associated with the Late Cretaceous-Palaeocene closure of the Tethyan Ocean, and formed during the transition from an extensional to a compressional regime. Palaeogene nappes that typically limit the exposure of ore bodies indicate a pre-Palaeocene age of ore formation. Host rock lithology, ore mineralogy, fluid inclusion, and sulphur + lead isotope data indicate that the metals were most probably leached from a crustal source such as clastic rocks or a crystalline massif, and transported by chloride-rich hydrothermal solutions to the site of deposition. Localization of the ore deposits on autochthonous basement highs indicates long-term basinal fluid migration, characteristic of MVT depositional processes. The primary MVT ores were oxidized in the Miocene, resulting in deposition of Zn-carbonate and Pb-sulphate-carbonate during karstification. The ores underwent multiple cycles of oxidation and, in places, were re-deposited to form clastic deposits. Modified deposits resemble the 'wall-rock replacement' and the 'residual and karst fill' of non-sulphide zinc deposits and are predominantly composed of smithsonite


Giant pockmarks in a carbonate platform (Maldives, Indian Ocean), 2011, Betzler C. , Lindhorst S. , Hubscher C. , Ludmann T. , Furstenau J. , Reijmer J.

Circular structures and depressions in carbonate platforms are known to represent karst chimneys or sinkholes which form as a response to rock solution. This formation mechanism is plausible for shallow-water carbonates which lie in the reach of meteoric diagenesis or fresh-water lenses. Circular structures which occur in deeper waters, however, need an alternative interpretation. Such an example of sea-floor depressions in more than 300. m deep waters occurs in the Inner Sea of the Maldives carbonate platform in the Indian Ocean. The structures were mapped with multibeam and Parasound, multi-channel seismics were used to link the depressions with structures at depth. The circular depressions have diameters of up to 3000. m and depths of up to 180. m. The craters are interpreted as pockmarks formed through the venting of gas and fluids. Gas and fluid lenses below the pockmarks are reflected by bright spots in the seismic sections as well as a reduction of the instantaneous frequency. These areas at depth are linked to chimneys connected to faults and drowned Oligocene carbonate banks. A model is presented that relates the different forms and sizes of the structures to distinct development stages of sea floor deformation to one process. Early stages of gas and fluid migration into the shallow part of the sedimentary succession induce formation of dome-shaped bodies. Initial gas and fluid escape to the sea floor is reflected by the formation of sand volcanoes and aligned small pockmarks. Active pockmarks are the deepest, and have the shape of truncated cones in cross section. Mature pockmarks are characterized by erosion of the flanks of the structure by bottom currents. Late stage pockmarks are bowl-shaped in cross section, and are to different degrees filled by drift sediments. Packages of strata revealing high reflection amplitudes and high interval velocities interpreted as microbially-mediated carbonate precipitates underlie some of the pockmarks. The pockmarks in the Maldives show that circular structures other than solution-related features can be abundant in carbonate platform deposits and that such structures may be more abundant in the geological record of carbonate platforms as previously thought. Pockmarks in the Maldives indicate that the archipelago is an example of a hydrocarbon system which consists of an isolated oceanic carbonate platform overlying a volcanic basement and lacustrine source rocks.


Modelling hydrostratigraphy and groundwater flow of a fractured and karst aquifer in a Mediterranean basin (Salento peninsula, southeastern Italy), 2012, Giudici M. , Margiotta S. , Mazzone F. , Negri S. , Vassena C.

The control exerted by the hydrostratigraphic structure on aquifer recharge, groundwater flow and discharge along the coastal areas of a Mediterranean basin (Salento peninsula, about 5,000 km2 wide, southern Italy) is assessed through the development and application of a groundwater flow model based on the reconstruction of the hydrostratigraphic architecture at the regional scale. The hydrostratigraphic model, obtained by processing surface and subsurface data, is applied to map the top of the main aquifer, which is hosted in the deep hydrostratigraphic unit corresponding to Cretaceous and Oligocene limestones with complex geometrical relationships with the sea. It is also used to estimate the aquifer recharge, which occurs by percolation through overlying younger sediments with low permeability. These data are completed with information about the soil use to estimate water abstraction for irrigation and with literature data to estimate the water abstraction for drinking and industrial purposes. The above-sketched conceptual model is the basis for a finite difference groundwater 2D pseudo-stationary flow model, which assumes the following fundamental approximations: the fractured and karst limestone hydrostratigraphic unit can be approximated, at the model scale, as a continuous medium for which the discrete Darcy’s law is valid; the transition zone between salt and fresh water is so small with respect to the grid spacing that the Ghyben–Herzberg’s approximation for a sharp interface can be applied. Along the coastline different boundary conditions are assigned if the top of the limestone hydrostratigraphic unit lies either above the sea level (the aquifer has a free surface and fresh water is drained), or below the sea level (the aquifer is under pressure and the contact with sea occurs off-shore). The groundwater flow model correctly predicts the areas where the aquifer is fully saturated with salt water.


Environmental Hydrogeological Study of Louros watershed, Epirus, Greece, 2012, Konstantina Katsanou

The present study aims to describe and characterize the Ionian zone karst formation concerning the karstification grade of carbonate formations and the development of aquifers, through the hydrogeological study of Louros River drainage basin, considering hydrological, hydrogeological and meteorological data, as well as major, trace element, rare earth element and isotope concentrations. It also aims to investigate basic karst properties such as storativity, homogeneity, infiltration coefficients and the parameters of the Louros basin hydrological balance.

To accomplish this aim daily discharge measurements obtained from Public Power Corporation at the Pantanassa station during the years 1956-1957, along with random discharge measurements from 15 springs along the basin performed by IGME between the years 1979-1989, daily meteorological data from 18 stations and 18 sets of potentiometric surface measurements from 38 sites were compiled. Additionally, chemical analyses on major and trace element concentrations of 42 rock samples and of five sets of water samples from 64 sampling sites, along with fourteen sets of successive periods in order to study the seasonal variation in the chemical composition of 11 springs and REE concentrations of 116 water samples. Moreover isotope ratios from 129 rain samples collected at five different altitudes, 331 samples of surface and groundwater samples, radon measurements on 21 groundwater samples and microbiological on 46 samples of surface and groundwater were evaluated. Daily runoff and random spring discharge missing data were completed applying the SAC-SMA and MODKARST simulation algorithms and the values of these parameters for the duration of the research (2008-2010) were predicted. The accuracy of the predicted values was tested applying statistical methods but also against observed values from in situ measurements performed during the same period (2008-2010).

Louros River drainage basin is located at the southern part of Epirus and covers an area of 953 km2. It is elongated and together with the adjacent basin of River Arachthos they constitute the major hydrographic systems discharging in the Amvrakikos Gulf. The main morphological features of the basin are elongated mountain ranges and narrow valleys, which are the result of tectonic and other geological processes mainly controlled by the limestone-“flysch” alternations. The length of the river’s major channel, which is parallel to the major folding direction (NNW-SSE), is 73.5 km. The mountainous part of the hydrogeological basin covers an area of 400 km2 and its endpoint was set at the Pantanassa station, where discharge measurements are performed. The underground limits of the basin coincides with the surface one, defined by the flysch outcrops at the western margin of the Ziros-Zalongo fault zone to the South, the application of isotope determinations and hydraulic load distribution maps at the North and East.

Geologically, Louros River drainage basin is composed of the Ionian zone formations. Triassic evaporites constitute the base of the zone overlain by a thick sequence of carbonate and clastic sedimentary rocks deposited from the Late Triassic to the Upper Eocene. In more detail, from base to top, the lithostratigraphical column of the zone includes dolomite and dolomitic limestone, Pantokrator limestone, Ammonitico Rosso, Posidonia Shales, Vigla limestone, Upper Senonian limestone, Palaeocene-Eocene limestone and Oligocene “flysch”. The major tectonic features of the regions are folds with their axes trending SW-NE at the northern part and NNW-SSE to NNE-SSW southern of the Mousiotitsa-Episkopiko-Petrovouni fault system and the strike-slip fault systems of Ziros and Petousi.

The evaluation of the daily meteorological data revealed that December is the most humid month of the year followed by January, whereas July and August are the driest months. Approximately 40-45% of the annual precipitation is distributed during the winter time and 30% during autumn. The mean annual precipitation ranges from 897.4 to 2051.8 mm and the precipitation altitude relationship suggests an increased precipitation with altitude at a rate of 84 mm/100 m. The maximum temperature is recorded during August and it may reach 40°C and the minimum during January. The temperature variation with the altitude is calculated at 0.61°C/100 m. The maximum solarity time is 377.8 h, recorded during July at the Arta station. December displays the highest relative humidity with a value of 84.2% recorded again at the Arta station. The highest wind velocity values are recorded at the Preveza station and similar velocities are also recorded at the Ioannina station. The real evapotranspiration in Louros drainage basin ranges between 27-39%. The potential evapotranspiration was calculated from the Ioannina station meteorological data, which are considered more representative for Louros basin, at 785.8 mm of precipitation according to Thornthwaite and at 722.0 mm according to Penman-Monteith.

According to the SAC-SMA algorithm the total discharge (surficial and underground) for the years 2008-2010 ranges between 61-73% of the total precipitation. The algorithm simulates the vertical percolation of rainwater in both unsaturated and saturated zones taking into account 15 parameters including the tension water capacity of the unsaturated zone, the maximum water storage capacity of both unsaturated and saturated zones, the water amount escaping into deeper horizons and not recorded at the basin’s outlet, the percentage of impermeable ground which is responsible for instant runoff, etc. These parameters are correlated to the hydrograph and are recalculated according to it. Two interesting aspects were pointed out from the discharge measurements and the algorithm application. The first is related to the maximum amount of free water, which can be stored at the basic flow of the karstic system, which is very high for the whole basin, reaching 1200 mm of precipitation and the second is the amount of water filtered to the deeper horizons, which reaches 0.098.

The discharge of individual karstic units was simulated applying the specialized MODKARST code. The code, which transforms precipitation to discharge resolving mathematical equations of non-linear flow using the mass and energy balance, successfully completed the time series of available data of spring discharge measurements for the period between the years 2008-2010.

Additionally, a number of useful parameters including spring recharge, delay period between precipitation and discharge, the storage capacity of the discharge area were also calculated by the MODKARST code. These data enabled the calculation of the annual infiltration coefficient for each one of the 15 springs and for the whole basin; the latter was found to range between 38-50% of annual precipitation. The total supply area was estimated approximately at 395 km2, which is consistent with the area of Louros hydrogeological basin calculated from hydrogeological data.

The 18 sets of water table measurements, each one corresponding to a different period, revealed that the aquifers of the intermediate part of Louros basin, which are developed in Quaternary alluvial sediments, are laterally connected to the carbonate formations of the individual karstic spring units, forming a common aquifer with a common water table.

Groundwater flow follows a general N-S direction from the topographic highs to the coastal area with local minor shifts to NE-SW and NW-SE directions. The artificial lake at the position of the Public Power Corporation’s Dam at the south of the region is directly connected to the aquifer and plays an important role in water-level variation. The water table contours display a higher gradient to the southern part due to the decreased hydraulic conductivity of the limestones close to Agios Georgios village. The decreased hydraulic conductivity is believed to be the reason for the development of the homonymous spring although the hydraulic load distributions suggest the extension of the aquifer to the south and a relation to the water level in Ziros Lake, boreholes and the Priala springs. The hydraulic gradient in the broader region ranges between 4-16‰. The absolute water level variation between dry and humid season ranges from 2 m at the South to 15-20 m to the North with an average of 9 m.

The hydrological balance of Louros River mountainous basin according to the aforementioned data is calculated as follows: The total precipitation between the years 2008-2010 ranged between 5.67E+08-9.8E+08 m3 and the discharge at Pantanassa site between 3.47E+08-6.83E+08 m3. The real evapotransiration ranged between 29-39% of the precipitation. The total discharge (runoff and groundwater) accounted for 61-73% of the precipitation, whereas the basic flow due to the percolation ranged between 34-38%. Considering a mean water level variation of 9 m, between the dry and humid season, the water amount constituting the local storage is 2025Ε+07 m3.

Statistical evaluation on spring discharge data and the recession curves analysis revealed three distinct levels with diverse karstic weathering along Louros basin coinciding to the upper, intermediate and low flow of Louros River, respectively. The developed karstic units are generally complex but simple individual units develop as well. The response of spring discharge to the stored water amounts is immediate but with relatively large duration suggesting the storage of large quantities of water and a well-developed system of karstic conduits, which however has not yet met its complete evolution. The karst spring’s units are homogeneous and each one is distinguished from different recession coefficients.

The three levels of flow are also distinguished from the duration curves, which point to individual units upstream, complex units receiving and transmitting water to the adjacent ones in the middle part and complex that only receive water from the upper. This distinguishment is also enhanced by the groundwater’s major ion concentrations, which reveal Ca-HCO3 water-type upstream, along with the isotopic composition at the same part. The prevalent Ca-HCO3-Cl-SO4 water-type in the middle part, the Na-Ca-Cl-SO4 water-type downstream and isotope variation confirms this distinguishment. Moreover, REE variation is also consistent with the three levels. The assumption of relatively large stored water reserves, which contribute to analogous “memory” of spring karstic units, as pointed out by autocorreletion functions is enhanced from SAC-SMA algorithm which premises an increased capacity at the lower zone of basic flow, as well as from the hydrochemical and isotopic composition of groundwater. Monitoring of the seasonal variation in groundwater composition revealed minor variations of hydrochemical parameters and remarkably stable isotopic composition. Both aspects can be explained by the existence of a considerable water body acting as a retarder to external changes.

The crosscorrelation functions suggest a well-developed karstic system, which however has not yet reached its complete maturity also confirmed from field observations. The same conclusion is extracted from the homogeneous evolution at the interval of each karstic unit as demonstrated from recession curves on spring hydrographs.

The results from hydrochemical analyses also revealed the effect of evaporitic minerals and phosphate-rich rocks in groundwater composition and confirmed the hydraulic relationships between surface and groundwater.

The study of the isotopic composition also contributed to exclude the potential connection between the Ioannina and Louros basins, confirmed the meteoric origin of groundwater and revealed the effect of seawater in the chemical composition of few sampling sites.

The microbiological research only revealed minor incidents of contamination and significant attenuation of microorganisms during periods of high discharge.


NA JAVORCE CAVE A NEW DISCOVERY IN THE BOHEMIAN KARST (CZECH REPUBLIC): UNIQUE EXAMPLE OF RELATIONSHIPS BETWEEN HYDROTHERMAL AND COMMON KARSTIFICATION, 2013, Dragoun J. Ž, á, K K. Vejlupek J. Filippi M. Novotný, J. Dobeš, P.

 

The Na Javorce Cave is located in the Bohemian Karst, Czech Republic, near the Karlštejn castle, about 25 km SW of Prague. The cave was discovered as a result of extensive exploration including cave digging and widely employed capping of narrow sections. Exploration in the cave has already lasted 20 years. The cave is fitted with several hundred meters of fixed and rope ladders and several small fixed bridges across intra-cave chasms. Access to the remote parts of the cave is difficult because of long narrow crawl passages and deep and narrow vertical sections. The Na Javorce Cave became the deepest cave discovered to date in Bohemia with the discovery of its deepest part containing a lake in 2010. The cave was formed in vertically dipping layers of Lower Devonian limestone; it is 1,723 m long and 129 m deep, of which 9 m is permanently flooded (data as of December 2012). The cave is polygenetic, with several clearly separable evolutionary stages. Cavities discovered to date were mostly formed along the tectonic structures of two main systems. One of these systems is represented by vertical faults of generally N-S strike, which are frequently accompanied by vein hydrothermal calcite with crystal cavities. The second fault system is represented by moderately inclined faults (dip 27 to 45°, dip direction to the W). Smaller tube-like passages of phreatic morphology connect the larger cavities developed along the two above-mentioned systems. The fluid inclusion data obtained for calcite developed along both fault systems in combination with C and O stable isotope studies indicate that the hydrothermal calcite was deposited from moderately saline fluids (0.5 to 8.7 wt. % NaCl equiv.) in the temperature range from 58 to 98 °C. The fluids were NaCl-type basinal fluids, probably derived from the deeper clastic horizons of the Barrandian sedimentary sequence. The age of the hydrothermal processes is unknown; geologically it is delimited by the Permian and Paleogene. The hydrothermal cavities are small compared to cavities formed during the later stages of karstification. The majority of the known cavities were probably formed by corrosion by floodwater derived from an adjacent river. This process was initiated during the Late Oligocene to Early Miocene, as was confirmed by typical assemblage of heavy minerals identical in the surface river sediments and in clastic cave sediments. The morphology of most cavities is phreatic or epiphreatic, with only local development of leveled roof sections (“Laugdecken”). The phreatic evolution of the cave is probably continuing into the present in its deepest permanently flooded part, which exhibits a water level close to that of the adjacent Berounka River. Nevertheless, the chemistry of the cave lake differs from that of the river water. The cave hosts all the usual types of cave decoration (including locally abundant erratics). The most interesting speleothem type is cryogenic cave carbonate, which was formed during freezing of water in relation to the presence of permafrost during the Glacial period. The occurrence of cryogenic cave carbonate here indicates that the permafrost of the Last Glacial period penetrated to a depth of at least 65 m below the surface.


Caves in the Buda Mountains, 2015, LeélŐssy, Szabolcs

On the territory of Budapest, there are about 170 caves: mainly in the Rózsadomb (Rose Hill) area. The total known length of these caves (in the city) is more than 52 km. The caves of Budapest are hypogene (thermal karstic) caves, dissolved by mixing corrosion of ascending waters along tectonic joints. Therefore, the cave passages are totally independent of surface morphology, and there are no fluviatile sediments in the caves. The origin of the caves can be reconstructed from the careful reconstruction of underground circulation routes. The caves are characterized by varied morphological features: spherical cavities along corridors of various size, the walls and floors, sometimes even the ceilings, of which are well decorated with mineral precipitations (calcite, aragonite and gypsum, a total of almost 20 minerals), the most common being botryoids, but dripstones are also common. The cave passages are mainly formed in the Eocene Szépvölgy Limestone Formation, but the upper part is often in Eocene-Oligocene Buda Marl. The deepest horizon is sometimes in the Triassic limestone (Mátyáshegy Formation). Based on U-series dating of their minerals, the Buda caves are very young (between 0.5 and 1 Ma).


Depth and timing of calcite spar and “spar cave” genesis: Implications for landscape evolution studies, 2015,

Calcite spar (crystals >1 cm in diameter) are common in limestone and dolostone terrains. In the Guadalupe Mountains, New Mexico and west Texas, calcite spar is abundant and lines small geode-like caves. Determining the depth and timing of formation of these large scalenohedral calcite crystals is critical in linking the growth of spar with landscape evolution. In this study, we show that large euhedral calcite crystals precipitate deep in the phreatic zone (400–800 m) in these small geode-like caves (spar caves), and we propose both are the result of properties of supercritical CO2 at that depth. U-Pb dating of spar crystals shows that they formed primarily between 36 and 28 Ma. The 87Sr/86Sr values of the euhedral calcite spar show that the spar has a signifi cantly higher 87Sr/86Sr (0.710–0.716) than the host Permian limestone (0.706–0.709). This indicates the spar formed from waters that are mixed with, or formed entirely from, a source other than the surrounding bedrock aquifer, and this is consistent with hypogene speleogenesis at signifi cant depth. In addition, we conducted highly precise measurements of the variation in nonradiogenic isotopes of strontium, 88Sr/86Sr, expressed as 88Sr, the variation of which has previously been shown to depend on temperature of precipitation. Our preliminary 88Sr results from the spar calcite are consistent with formation at 50–70 °C. Our fi rst U-Pb results show that the spar was precipitated during the beginning of Basin and Range tectonism in a late Eocene to early Oligocene episode, which was coeval with two major magmatic periods at 36–33 Ma and 32–28 Ma. A novel speleogenetic process that includes both the dissolution of the spar caves and precipitation of the spar by the same speleogenetic event is proposed and supports the formation of the spar at 400–800 m depth, where the transition from supercritical to subcritical CO2 drives both dissolution of limestone during the main speleogenetic event and precipitation of calcite at the terminal phase of speleogenesis. We suggest that CO2 is derived from contemporaneous igneous activity. This proposed model suggests that calcite spar can be used for reconstruction of landscape evolution


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