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Speleology in Kazakhstan

Shakalov on 04 Jul, 2018
Hello everyone!   I pleased to invite you to the official site of Central Asian Karstic-Speleological commission ("Kaspeko")   There, we regularly publish reports about our expeditions, articles and reports on speleotopics, lecture course for instructors, photos etc. ...

New publications on hypogene speleogenesis

Klimchouk on 26 Mar, 2012
Dear Colleagues, This is to draw your attention to several recent publications added to KarstBase, relevant to hypogenic karst/speleogenesis: Corrosion of limestone tablets in sulfidic ground-water: measurements and speleogenetic implications Galdenzi,

The deepest terrestrial animal

Klimchouk on 23 Feb, 2012
A recent publication of Spanish researchers describes the biology of Krubera Cave, including the deepest terrestrial animal ever found: Jordana, Rafael; Baquero, Enrique; Reboleira, Sofía and Sendra, Alberto. ...

Caves - landscapes without light

akop on 05 Feb, 2012
Exhibition dedicated to caves is taking place in the Vienna Natural History Museum   The exhibition at the Natural History Museum presents the surprising variety of caves and cave formations such as stalactites and various crystals. ...

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That strath terrace is an erosional remnant of an elevated broad river valley [16].?

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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 granite (Keyword) returned 31 results for the whole karstbase:
Showing 16 to 30 of 31
Evolution of river network at the 'Cevennes-Grands Causses' transition: Consequences for the evaluation of uplift, 2001, Camus H,
The Mediterranean catchment of the Cevennes (S. France) presents deep incision of the river network (fig. 1 and 2). Combined geomorphology and analyses of the residual sedimentary formations allows to reconstruct a complex history of river network evolution, including capture of tributaries of the Herault River (fig. 1, 2 and 3). The history of uplift of the upstream drainage area could be estimated from the provenance studies of the fluvial and karstic deposits, however river incision is also controlled sea-level changes and differential erosion, which makes reconstruction more complex. Allochthonous clasts types Analyses of allochtonous deposits on the Grands Causses surface reveals different origin for sediments from the hill top and the Airoles valley (fig. 4b), which was previously unrecognised. Facies 1 is found on the highest points of the Grands Causses surface (well sorted rounded quartz pebbles in red shale matrix) it corresponds to a weathered residual sediments (dismantling of an ancient cover). Facies 2 is found on the slope of the Airoles Valley (fig. 7). It consists of alluvial crystalline poorly sorted clasts with outsized clasts (up to 50cm) of quartz-vein, schists in a matrix of shales and sand (weathered granite). Between the hill tops and the Airoles Valley, karstic network presents a sediment fill with clasts reworked from facies I and facies 2 (fig. 6). Airoles valley model : an example of diachronic formation of drainage network The Airoles dry valley stretches on the Grands Causses from the north (700 m) to the south into the present thalweg line of the Vis canyon (500 m) (fig. 1b & 3). Crystalline deposits witness an ancient catchment in the Cevennes. Presently, the catchment in the crystalline basement is disconnected and captured by the Arre River flowing eastwards (fig. 3 & 4a). The profile of the Airoles abandoned valley connects with the present Vis Canyon, therefore, at the time of capture, incision of the Vis canyon had reached its present altitude (fig. 4a). The geomorphologic evolution of this area took place in three stages (fig. 8). 1) The Grands Causses acted as piedmont for the crystalline highlands of the Massif Central (fig. 8A). A latter karstic evolution (tropical climate) allowed the weathered residual sediments (facies 1) (fig. 8A). 2) Incision of the Vis karstic canyon implies that the Herault incision and terraces (facies 2) (fig, 8B) of the Airoles valley occurred during this stage. 3) The Arre valley head propagates westward by regressive erosion and finaly captured the Airoles river crystalline catchment (fig. 8C). Consequence for the Cevennes uplift and hydrographic network development Although the values of present vertical incision in the Vis canyon and in the Arre valley are similar, but they achieved at different time. In addition, the narrow and deep canyon of the Vis is due to vertical incision from the karstic surface of the Grands Causses, whereas the Arre wide valley results from (a younger) lateral slops retreat from a low Herault base-level. The Vis karstic canyon developed in a similar way to the major karstic canyons of both Mediterranean and Atlantic catchment (i.e. Tarn). This rules out a Messinian Mediterranean desiccation as incision driving mechanism and suggests tectonic uplift of the Cevennes and surrounding areas. The Tam being already incised by 13 My [Ambert, 1990], it implies a Miocene age for the incision. Conclusion The amplitude of the vertical incision cannot therefore be used in a simple way to interpret the uplift history of the basement. Consequently, geomorphologic analysis appears to be a prerequisite to distinguish the part played by each factor, and to select the site of uplift measurement

Engineering impacts of karst: A review of some engineering aspects of limestone weathering with case studies from Devon and Ireland, MSc Thesis, 2001, Pressdee, C.

The thesis aims to review the nature of karstic limestone terrains and the implications for engineering practices as a result of the uniquely difficult ground conditions they present. Case studies are included to highlight two very different, yet apparently common, engineering problems on karst. This abstract deals only with Linhay Hill Quarry in Ashburton, Devon where pinnacled rockhead and clay infilled dissolution pipes present problems in the extraction and processing of the limestone for use as aggregate.
The quarry has been in existence for over a hundred years and the current owners are drilling and blasting the Devonian limestone and processing it for a variety of purposes; namely aggregates for concrete, macadam and unbound applications. In the quarry, the rock is fairly evenly bedded and dipping towards the east. Near the ground surface it is extensively solution weathered to form a karst surface, which is now buried by more recent deposits. The extensive karst topography gives considerable problems, currently on the north side, where the intimate mixture of solution weathered limestone and later infilling clays and sandy sediments makes drilling and blasting difficult and contaminates the limestone material.
On the basis of the work carried out, the following summary of findings is presented:
Using published engineering classification schemes; the Chercombe Bridge Limestone in and around Linhay Hill Quarry has been classified as Class III to IV Karst ('Mature' to 'Complex' Karst, Waltham, 1999).
• The origin of the karst is proposed to be the result of a combination of subtropical climate and localised valley conditions in the early Tertiary. Weathering and erosion of the Dartmoor granite and adjacent Cretaceous rocks provided fluvial sediment to subsequently infill the solution channels and cavities in the limestone.
• The physical effects of weathering have been shown to reduce the strength and density of the limestone whilst increasing the water absorption. This has implications for the quality of aggregate produced in the quarry.
• The chemical effects of dolomitisation and solutional weathering have been shown to produce a highly variable material in the quarry.
• Residual insoluble minerals were found to be randomly distributed and exhibited typically high densities, high absorptions and high clay and iron oxide/hydroxide contents.
• The nature of the infilled karst together with the effects of weathering mentioned above has significantly affected the workings of the quarry with considerable cost implications. They are listed (in no particular order) as follows:
Overburden stripping extremely time consuming and costly.
Increased drilling times through clay infilled fissures/cavities.
Enforced blast hole surveying techniques due to variable ground.
Enforced blast charge restriction resulting in reduced primary fragmentation.
Induced dolines in the surrounding farmland.
Costs of washing/scrubbing of clay coated 'contaminated' rock.
Clay materials not always removed resulting in reduced efficiency of processing plant.
Quality of aggregates impaired by variable rock properties and presence of clay.
Implications for concrete and mortar include potentially reduced workability strength and durability


Colonization by aerobic bacteria in karst: Laboratory and in situ experiments, 2004, Personne J. C. , Poty F. , Mahler B. J. , Drogue C. ,
Experiments were carried out to investigate the potential for bacterial colonization of different substrates in karst aquifers and the nature of the colonizing bacteria. Laboratory batch experiments were performed using limestone and PVC as substrates, a natural bacterial isolate and a known laboratory strain (Escherichia coli [E. coli]) as inocula, and karst ground water and a synthetic formula as growth media. In parallel, fragments of limestone and granite were submerged in boreholes penetrating two karst aquifers for more than one year; the boreholes are periodically contaminated by enteric bacteria from waste water. Once a month, rock samples were removed and the colonizing bacteria quantified and identified. The batch experiments demonstrated that the natural isolate and E. coli both readily colonized limestone surfaces using karst ground water as the growth medium. In contrast, bacterial colonization of both the limestone and granite substrates, when submerged in the karst, was less intense. More than 300 bacterial strains were isolated over the period sampled, but no temporal pattern in colonization was seen as far as strain, and colonization by E. coli was notably absent, although strains of Salmonella and Citrobacter were each observed once. Samples suspended in boreholes penetrating, highly fractured zones were less densely colonized than those in the borehole penetrating a less fractured zone. The results suggest that contamination of karst aquifers by enteric bacteria is unlikely to be persistent. We hypothesize that this may be a result of the high flow velocities found in karst conduits, and of predation of colonizing bacteria by autochthonous zooplankton

Etude des palokarsts des environs de Saint-Remze (Ardche, France) : mise en vidence dune rivire souterraine fossilise durant la crise de salinit messinienne, 2005, Martini, Jacques
Paleokarst investigation near Saint-Remze, Ardche, France discovery of an underground river fossilized during the Messinian salinity crisis - The paleokarst features studied in this paper are hosted in Lower Cretaceous limestone and generally appear as filled caves, subsequently de-roofed by denudation. The most important of them forms a sequence of segments developed at a relatively constant elevation of 360-380 m above sea level and can be traced over a length of 5.2 km. The ancient cave passages generally appear as soil covered bands, 5 to 20 m in width and limited on both sides by limestone outcrops. At surface the nature of the cave filling is revealed mainly by scattered blocks: calcite from speleothems and calcified clay, silt, sand and breccia. In the best preserved places, the earth band lies in a trench, where the walls may display a cave morphology and where the filling is often exposed in a undisturbed state. Three types of detrital cave filling have been identified, which in stratigraphical order are as follows: 1) Beige-grey silt, sand and microconglomerate of immature alluvials, with elements of Paleozoic granites and metamorphic rocks, and Upper Miocene volcanics, both originating from the Cvennes Mountains 30 km to the NW. The lithological composition is comparable to the recent alluvials of the Paleokarst investigation near Saint-Remze, Ardche, France discovery of an underground river fossilized during the Messinian salinity crisisArdche River, which is flowing a few kilometers to the SW and is deeply entrenched into a canyon at elevations of 40 to 80 m. The karst context, combined with the biostratigraphical data obtained from rodent molars in the alluvials, suggests an Uppermost Miocene age, comprised between ~5.8 and ~5.45 Ma. 2) Red mature alluvials and colluvials originating from local reworking of surficial karst residuals. At one spot they gave a paleontological age of 3.6 to 3.0 Ma, but from the local karst context one may expect ages from final Miocene to Pleistocene in other spots. 3) Monogenic breccia generated from wall gelifraction, which is Pleistocene after rodent molars found in two places. The paleocave is visualised as formed by an underground stream fed from swallow-holes on the bank of the Ardche River, when it was flowing more than 300 m higher than its actual bed. With regard to its relatively constant elevation and a discordant relationship with the country rock bedding, it is interpreted as a vadose cave controlled by a paleo-water-table. The other fillings (2 and 3) were deposited during subsequent vadose speleogenesis and after considerable water-table lowering. The elevation of this fossilised underground river coincides fairly well with the pre-salinity crisis abandonment surface (5.52 Ma), which is evidenced in the area by high perched gravel relics. The end of the speleogenesis could have taken place just before this event (~5.6 Ma) or at an age not younger than ~5.45 Ma. In the latter possibility, speleogenesis had to be working before the regressive erosion generated by the drastic lowering of the Mediterranean Sea [5.52 to 5.33 Ma, Clauzon et al, 2005 ] reached the area and de-watered the deep karst aquifer. This fossil underground river provides also information about the morphological evolution of the area. For instance the nature of the immature alluvials suggests that the torrential regime of the Ardche was about the same than today. It also indicates that the important and famous cave systems in the area (Grotte de Saint-Marcel, Aven dOrgnac, Systme de Foussoubie, Grotte Chauvet), which are developed at lower elevations, cannot be older than ~5.6 Ma and most likely formed mainly during the Plio-Pleistocene, although most of them have been initiated during the salinity crisis.

Investigation of Morphology Hydrogeology Relations in Harmanköy Beyyayla (Bilecik, Turkey) Karst System, PhD thesis, 2005, Aydin, H.

Harmanköy – Beyyayla Karst System (HBKS) forms the highlands in the Central Sakarya Basin. HBKS which is made of Jurassic Bilecik limestone is located within the province boundaries of Bilecik and Eskişehir and extends over a surface area of 49.5 km2. In this study, the HBKS whose boundary conditions are well defined was investigated in terms of morphology – hydrogeology relationships. Within this context, hydrogeological conceptual model of the study area was developed based on the physical parameters such as geology, tectonic, morphology and dynamic properties such as precipitation regime, infiltration, recharge, flow and storage.
Upon the evaluation of morphological, hydrologic, hydrogeological and hydrodynamic properties, it was concluded that HBKS consists of three distinct subsystems, namely the Beyyayla, Döşkaya and Nardın subsystems. It was further determined that Beyyayla and Döşkaya subsystems are similar by the properties mentioned above, while the Nardın subsystem differs from these two subsystems.
Recharge in HBSK occurs in two different forms; allogenic-point and autogenic-diffuse. Surface waters which are drained from Paleozoic age granites located in Beyyayla and Döşkaya subsystems’ recharge these systems as allogenic-point from Beyyayla and Tozman sinkholes. On the other hand, precipitation which falls on the limestone rock-mass supplies the autogenic diffuse recharge to the systems. Recharge to the Nardın subsystem on the other hand, is autogenic diffuse from direct precipitation on to the limestone area. The Qmax/Qmin ratio and the variation coefficient (CV) of chemical compositions of the springs which drain these subsystems, imply that concentrated flow is dominant in all these three systems. In addition, trace experiments carried out in Beyyayla and Döşkaya subsystems suggest that the flow is turbulent and rapid within the well-developed karstic channels. Advective-dispersive transport is controlling the solute transport in the system.
It was speculated that the energy gradient is more important than tectonic, lithologic characteristics and climatic changes in karst evolution Beyyayla and Döşkaya subsystems. Lowering of erosion base caused exposure of granites which consequently supplied the allogenic-point recharge to these subsystems. This was resulted in distinct morphologic, hydrologic and hydrodynamic properties of the subsystem.
Advisor: Assoc. Prof. Dr. Mehmet EKMEKÇİ, Hacettepe University, Department of Geological Engineering, Hydrogeological Engineering Division


A survey of the groundwater fauna of the Scilly Isles, United Kingdom, 2008, Knight, Lee R F D.
This report details the results of a survey of wells and springs on the Isles of Scilly. The survey was conducted in order to ascertain if Niphargus glenniei and other stygobitic species might be present in the fractured granite aquifers of the archipelago. A variety of epigean freshwater taxa were recorded but no stygobitic species were found. White specimens (possibly stygophilic) of the cyclopid copepod Diacyclops bisetosus were recorded from two covered well shafts on the island of St Agnes.

ÁREAS CÁRSTICAS, CAVERNAS E A ESTRADA REAL, 2008, Travassos L. E. P. , GuimarÃ, Es R. L. , Varela I. D.
Throughout the world, many natural landscapes have been preserved for their historical and cultural values, as well as their environmental importance. The Estrada Real (originally the historic route for the movement of precious metals and gemstones in colonial Brazil) has been re-opened to encourage the flow of tourists to the region and strengthen the economic basis of the municipalities involved. This paper provides a list of some 126 caves along this route registered in the Brazilian National Register of Caves (CNC). These caves are located in various lithologies: limestone, dolomite, quartzite, and granite. This survey identified the caves, but should be extended systematically in the future. The topic is far from exhausted here, but should introduce a new approach for academic studies concerned with geotourism in the country.

STYLES OF HYPOGENE CAVE DEVELOPMENT IN ANCIENT CARBONATE AREAS OVERLYING NON-PERMEABLE ROCKS IN BRAZIL AND THE INFLUENCE OF COMPETING MECHANISMS AND LATER MODIFYING PROCESSES, 2009, Augusto S. Auler

A significant proportion of the karst areas in Brazil develop over ancient cratonic or tectonically stable zones overlying Precambrian quartzites or Archaean crystalline basement (granite, gneiss, schist). In such settings, due to the low transmissivity and highly anisotropic nature of the bedrock, major groundwater flow of regional scale tends to be restricted, and diffuse ascending cross-formational flow into the carbonate is limited to a few favourable input zones. Nevertheless, caves displaying hypogene features occur in several areas, although few contain the full suite of speleogenetic forms commonly found in “classic” better studied areas of Europe and North America. Major known hypogene caves in Brazil tend to be located in zones bordering the more stable cratonic areas, such as in Vazante and Toca da Boa Vista karst areas, where fault zones are likely candidates for providing ascending flow paths towards the carbonate. The absence of transmissive beds above the carbonate limits the existence of outflow routes. Brazilian hypogene caves develop in mostly horizontally bedded or gently dipping bedrock and typically do not display the three-dimensional character of many hypogene caves elsewhere. The speleogenetic role of competing mechanisms such as sulphuric acid dissolution due to pyrite oxidation and condensation corrosion tend to overprint original forms as well as produce similar convergent features.


Cave Millipeds of the United States. IX. A New Species of the Genus Taiyutyla (Diplopoda, Chordeumatida, Conotylidae) from Caves in Sequoia and Yosemite National Parks, California, USA, 2011, Shear William A. , Krejca Jean K.

During surveys of cave life in Sequoia and Kings Canyon National Parks and
Yosemite National Park, Taiyutyla loftinae, a new species of conotylid milliped, was collected and is described below. The new species occurs in eleven marble caves distributed throughout Sequoia National Park (Tulare County, California), two granite talus caves, and a single surface locality in Yosemite National Park (Mariposa County, California) and is best considered troglophilic, not troglobitic.


Hydrochemistry of geothermal water in Tianshui and adjacent area, Gansu province, China, 2012, Wen Y. , Wang N. , Hu Z.

A geochemical study on thermal water has been carried out in Tianshui and its adjacent area, Gansu province, China. Chemical and isotopic contents were employed in the investigation on the origin and evolution of thermal water and the evaluation of reservoir temperature in the geothermal systems. Thermal waters in Wushan and Tianshui are characterized by outlet temperatures from 15 to 38_C and low TDS (226–255 mg/L), defined as bicarbonate water. Its origin may be attributed to the interaction between meteoric rain, biotite plagioclase gneiss and carbonate reservoir rocks. In contrast, thermal waters in Tongwei and Qingshui have higher outlet temperatures of 25–54.2_C and a moderate TDS of 915–1,793 mg/L, regarded as sulfate waters. These sulfate waters may arise from the interaction between meteoric water, granite and amphogneiss. Isotopic data presented here suggest that thermal waters in the study area have a meteoric origin without being significantly effected by water–rock isotope exchange. Chemical geothermometry indicates the existence of a deep geothermal reservoir of low-to-medium enthalpy (70–111_C) in the Tianshui study area.


Electrical Tomography Applied to the Detection of Subsurface Cavities, 2013, Martineslpez J. , Rey J. , Dueas J. , Hidalgo C. , Benavente J.

We have analyzed the geoelectric response produced by three cavities cut into different geological substrata of granite, phyllite, and sandstone that had previously been characterized by direct methods. We also examined a mining void excavated in granite. In each case, we applied three different geoelectric arrays (Wenner-Schlumberger, Wenner and dipole-dipole) and several inter-electrode spacings. The survey results suggest that electrical resistivity tomography is a viable geophysical tool for the detection and monitoring of mining voids and other subsurface cavities. The results vary depending on a wide range of factors, such as the depth and diameter of the cavity, the multi-electrode array used, the inter-electrode spacing, the geological model, and the density of the data. The resolution capacity of the Wenner- Schlumberger array for the detection of these cavities was greater than that of the Wenner array and slightly better than the dipole-dipole. There is a direct relationship between inter-electrode spacing and diameter of the cavity. In general, we observed a loss of resolution as the distance between the electrodes increased. The most efficient detection was achieved when the inter-electrodes distance was less than or equal to the diameter of the cavity itself. In addition, cavity detection became increasingly less precise with its depth beneath the surface. Cavities with a radius of about 1.5 m were located by both the Wenner- Schlumberger method and the dipole-dipole at depths of more than 4.6 m, which means that prospecting can be carried out at depths 3 times the radius of the cavity.


Deglaciation of the eastern Cumbria glaciokarst, northwest England, as determined by cosmogenic nuclide (10Be) surface exposure dating, and the pattern and significance of subsequent environmental changes, 2013, Wilson P. , Lord T. , Rods .

Four erratic boulders of Shap granite on the limestone terrain of eastern Cumbria have yielded cosmogenic nuclide (10Be) surface exposure ages that indicate the area was deglaciated c.17 ka ago. This timing is in accord with other ages pertaining to the loss of glacial ice cover in the Yorkshire Dales and north Lancashire, to the south, and the Lake District, to the west, and constrains the resumption of landscape (re)colonization and surface and sub-surface karstic processes. Marked shifts in climate are known to have occurred since deglaciation and combined with human impacts on the landscape the glaciokarst has experienced a complex pattern of environmental changes. Understanding these changes and their effects is crucial if the 'post-glacial' evolution of the glaciokarst is to be deciphered.


VALLEY INCISION IN THE NÍZKE TATRY MTS. (SLOVAKIA) ESTIMATED BASED ON PALEOMAGNETIC AND RADIOMETRIC CAVE SEDIMENT DATINGS, 2013, Kadlec J. Bella P. Č, í, ž, Ková, K. Granger D. E. Hercman H. Holú, Bek P. Chadima M. Orvoš, Ová, M. Pruner P. Schnabl P. Š, Lechta S.

 

Up to eleven horizontal cave levels occur at different altitudes in Jánska, Demänovská and Mošnická karst valleys in the Nízke Tatry Mts. Most of the caves are filled with allochthonous sediments transported from the area formed mostly by granite. The cave levels were filled with fluvial sediments in dependence on the valleys incision caused by Neogene and Pleistocene uplift of the mountain range. The fluvial sediments are intercalated with, or capped, by flowstone layers in the caves. The paleomagnetic polarities measured both in clastic and chemogenic sediments indicate the age of deposition. Based on obtained polarity data we are able to distinguish cave sediments deposited during the Brunhes, Matuyama and Gauss chrons. The paleomagnetic interpretation was partly verified by U-series datings of flowstones preserved in the sedimentary sections. Except for the horizontal cave levels located in the karst valleys, additional large cave systems were found at extremely high altitudes in the Nízke Tatry Mts. 600–700 m above the lowest horizontal cave level.


Karstification as a Predisposing Factor of Seismically Triggered Landslides: Case Study from the Crimean Mountains (Ukraine): Introduction to the Problem, 2013, Hradeck J. , Pnek T. , ilhn K. , Smolkov V.

Deep-seated gravitational deformations are significant denudational agents of rock slopes at the margins of karstified plateaus of the Crimean Mountains (CM). The CM evolved during Mesozoic–Cenozoic times as a response to the deformation between the Black Sea domain and East-European platform. The southwestern part of the area is characterized by steep, up to 1000-m-high coastal escarpments consisting of Late Jurassic limestones overlying tuff layers and weak Late Triassic flysch with sporadic small intrusions of Middle Jurassic diorites, gabbros and granites. Steep rock slopes contrast with elevated, highly karstified plateaus situated approximately 500–1300 m a.s.l. The aim of this article is to show long-term evolution of a giant rock slope failure close to the Black Sea coast in the southwestern tip of the CM near Foros Town. The failure evolved in highly anisotropic limestones overlying plastic flysch layers where the main head scarp follows a strike-slip fault. The Foros slope failure is an excellent demonstration of the significance of a preparatory stage in the evolution of large deep-seated slope deformations. Inherited and undisturbed horizontal slickensides on the sub-vertical, inactive fault surface serve as good evidence of significant extensional movement of the surface blocks away from the main headscarp. The studied deformation shows that in a relatively small area tensional (cutting) surfaces can be formed by a great variety of rock discontinuities such as the strike-slip fault, joints and steeply inclined bedding planes. The presence of well-developed, nowadays weathered, speleothems furthermore points to significant karstification that provided additional widening of spaces within rock mass. Gravitational movement destroyed and unroofed several cave systems originally presented at the former edge of a karst plateau. Our findings reveal that large rock slope failures can be added to the factors contributing to the evolution of unroofed caves. Although triggering factors of the activation of individual parts of slope deformations can be determined only hypothetically, lessons learned from widespread landslide activity during and after the 1927 Yalta earthquake and rainfall-driven landslides in the vicinity of Feodosia Town make us consider both seismic loading of slopes and high pore-pressures during heavy winter rainfalls or rapid spring snowmelt to be significant factors. Beside seismic activity, intensive Late Holocene slope processes can be attributed to intensive human activity.

 


CAVES AND KARST-LIKE FEATURES IN PROTEROZOIC GNEISS AND CAMBRIAN GRANITE, SOUTHERN AND CENTRAL SRI LANKA: AN INTRODUCTION, 2013, Osborne R. A. L. , Weliange W. S. , Jayasingha Pathmakumara, Dandeniya A. S. , Algiriya A. K. Prageeth P. & Pogson Ross E.

There has been little study of the geology and geomorphology of the caves and karst­like features developed in the Proterozoic gneiss and Cambrian granite of Sri Lanka. This lack of study is surprising given that caves and rockshelters in these rocks contain significant archaeological and cultural sites. Caves and karren, both mimicking those developed in carbonate rocks, have formed both in gneiss, which is the dominant rock type of the Proterozoic crust of the island and in granite. In addition to overhangs, boulder caves, soil pipes and tectonic caves, tunnel caves, arch caves and block breakdown caves of significant size are developed in siliceous rocks in Sri Lanka. while metamorphosed dolomites are interfoliated within the gneissic suite, simple removal of carbonate by solution from within the surrounding rock cannot account for all or most of the speleogenesis observed. while spalling and breakdown are responsible for cave enlargement, cave initiation is probably due to either phreatic solution of silicates and/or phantom rock processes. Speleothems and cave minerals including silicates, phosphates, gypsum, carbonates and niter are found in the caves. Active silicate speleothems are not restricted to joints and fissures and suggest that solution of silicates is currently occurring within the body of the rock in the vadose zone. while guano is the likely source of the phosphate, sulfate and nitrate, the source of the calcium in the carbonates remains unclear. Caves in the intrusive and metamorphic rocks of Sri Lanka are enigmatic. They are unexpectedly similar in appearance to their carbonate karst counterparts. Continuing research will allow them to hold a mirror to our understanding of speleogenesis, mineralization and sedimentation in carbonate karst caves.


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