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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 beach is a shore consisting of sand or gravel deposits [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 gravity (Keyword) returned 75 results for the whole karstbase:
Showing 16 to 30 of 75
Karstification and tectonic evolution of the Jabal Madar (Adam Foothills, Arabian platform) during the Upper Cretaceous, 2000, Montenat C. , Soudet H. J. , Barrier P. , Chereau A. ,
A palaeokarst system of Turonian age, located on the Arabian platform, at the front of the ophiolitic nappes of Oman (Jabal Madar, Adam foothills), is described and placed in its geodynamic context. The development of the karst network in a vadose context was favoured by an episode of fracturing (N-S to NW-SE fractures) that affected the Cenomanian platform carbonates of the Natih Formation. The karstic filling comprises two main types of speleothems: - laminated bioclastic calcarenites with graded bedding essentially deposited by gravity currents in a vadose regime; - crystallisation of large masses of white calcite in a saturated regime. The calcite was deposited during several episodes, and often constitutes most of the filling. The episode of uplift and emergence, accompanied by fracturing which favoured the development of the Madar karstic system, was probably induced by the swelling of the Arabian platform, in response to the initiation of the ophiolitic nappe obduction. Karstic filling probably occurred during the rise of marine level, what is suggested by mixing of vadose and marine influences (production of bioclastic calcarenites and later dolomitisation of these ones; crystallisation of white calcite of various origins as evidenced by cathodoluminescence data and carbonate isotopes). At the beginning of the Senonian, the Jabal Madar area was again submerged and incorporated in a relatively deep foreland basin where pelagic marls and turbidites were deposited (Muti Formation). The Jabal Madar (and its karstic system) and the whole of the Adam foothills were affected by folding towards the end of the Cretaceous, during the final phase of thrusting of the Omani nappes. The folding was strongly reactivated by post-obduction compressional movement which occurred during Miocene times

Age of the Sherman-Type Zn-Pb-Ag Deposits, Mosquito Range, Colorado, 2000, Symons D. T. A. , Lewchuk M. T. , Taylor C. D. , Harris M. J. ,
The Sherman-type Zn-Pb-Ag dolomite deposits in central Colorado are hosted in dolostones of the Early Mississippian Leadville Formation. Paleomagnetic analysis, using progressive alternating field and thermal demagnetization and isothermal remanent magnetization acquisition methods, was performed on specimens from samples at 37 sites in the Sherman-type Continental Chief, Peerless, Ruby, Sacramento, and Sherman deposits, in their host rocks, in the 72 Ma Pando Porphyry sill(s) and in the ~40 Ma Leadville-type Black Cloud massive sulfide deposit. Paleomagnetic fold, contact, and breccia tests were performed to test for the antiquity of the magnetizations. The results are interpreted to indicate that the Leadville carbonates were regionally dolomitized at ~308 {} 6 (1{sigma}) Ma in the Early Pennsylvanian and that the Sherman-type deposits were emplaced at ~272 {} 18 (1{sigma}) Ma during the Early Permian after northeast-trending block faulting, karstification, and ~4 {} 1 km of sedimentary burial, possibly as the result of subsurface gravity-driven fluid flow related to the Ouachita-Marathon orogen. Following late Ouachita-Marathon or earliest Laramide (Late Cretaceous) folding, the remanence in the Sherman-type deposits and the Leadville dolostone rocks within the contact alteration zone of the 72 Ma Pando Porphyry sill(s) was reset to acquire a Late Cretaceous normal characteristic remanent magnetization. Thereafter the Black Cloud Leadville-type massive sulfide deposit was magnetized in the Eocene to acquire a reversed polarity characteristic remanent magnetization that was not found in the Sherman-type deposits

Solutional and erosional morphology, 2000, Lauritzen Se. , Lundberg J.
Caves are produced through the action of speleogenetic agents acting under various constraints to produce speleogenetic facies. These facies, expressed at the meso- and micro-scale, reflect the major and minor speleogenetic agents that operated on that cave; they also reflect the history of the cave, both during speleogenesis proper and during the post-speleogenetic phase, in particular the most recent history. Geological control is evident through the association of caves with guiding voids (the singularities that govern permeability) and passage shape with rock chemistry (solubility). Hydrological control guides the locus and direction of dissolution; phreatic conditions support omnidirectional dissolution and thus hydraulically controlled tubular forms, while vadose conditions allow only unidirectional dissolution and thus gravity-controlled canyon forms and karren-like features. Of the micro-forms, scallops are specific flow indicators that yield both directional and quantitative information like flow rates and various hydraulic parameters specific to the cave passages. The presence of a sediment fill may further direct corrosion; in the phreatic zone this causes paragenesis; in the vadose zone, sediments cause lateral undercutting and eventually collapse. Vadose streams display many of the forms of surface streams, such as migrating meanders, entrenchment, rock-mill pot-holes, and waterfalls. Vadose shafts, dome-pits and condensation-corrosional forms are perhaps specific to the cave enviroment. The various vadose, phreatic and certain water-table-specific forms are, in combination, powerful methods for reconstructing phases of speleogenesis as well as external base levels. Combined with speleothem dating techniques, they become important methods for determining erosion rates and landscape evolution.

Quartzite caves in southern Africa, 2000, Martini J. E. J.
A number of karst systems occur in lower Precambrian and in Ordovician quartzite in Southern Africa. They are developed only in high rainfall areas. At the surface pinnacle fields and lapiaz are common, but the drainage remains surficial, except in very localized areas where dolines, swallow-holes, stream caves and resurgences occur. The underground channels seldom extend more than a kilometers upstream from the resurgences, and generally much less. Caves over 2 km in total passage length have been mapped. The speleogenesis is by initial weathering of the quartzite, which is transformed into crumbly material and then removed by piping, thus forming caves. Other types of caves have developed by the erosion of deeply weathered diabase sills intrusive into quartzite. Some caves were initiated by gravity rifting in quartzite and then enlarged by stream action.

Geochemical study of calcite veins in the Silurian and Devonian of the Barrandian Basin (Czech Republic): evidence for widespread post-Variscan fluid flow in the central part of the Bohemian Massif, 2000, Suchy V. , Heijlen W. , Sykorova I. , Muchez Ph. , Dobes P. , Hladikova J. , Jackova I. , Safanda J. , Zeman A.

Carbonate fracture cements in limestones have been investigated by fluid inclusion and stable isotope analysis to provide insight into fluid evolution and deformation conditions of the Barrandian Basin (Silurian–Devonian) of the Czech Republic. The fractures strike generally north–south and appear to postdate major Variscan deformation. The most common fracture cement is calcite that is locally accompanied by quartz, natural bitumen, dolomite, Mn-oxides and fluorite. Three successive generations of fracture-filling calcite cements are distinguished based on their petrographical and geochemical characteristics. The oldest calcite cements (Stage 1) are moderate to dull brown cathodoluminescent, Fe-rich and exhibit intense cleavage, subgrain development and other features characteristic of tectonic deformation. Less tectonically deformed, variable luminescent Fe-poor calcite corresponds to a paragenetically younger Stage 2 cement. First melting temperatures, Te, of two-phase aqueous inclusions in Stages 1 and 2 calcites are often around 2208C, suggesting that precipitation of the cements occurred from H2O–NaCl fluids. The melting temperature, Tm, has values between 0 and 25.88C, corresponding to a low salinity between 0 and 8.9 eq. wt% NaCl. Homogenization temperatures, Th, from calcite cements are interpreted to indicate precipitation at about 708C or less. No distinction could be made between the calcite of Stages 1 and 2 based on their fluid inclusion characteristics. In some Stage 2 cements, inclusions of highly saline (up to 23 eq. wt% NaCl) brines appear to coexist with low-salinity inclusions. The low salinity fluid possibly contains Na-, K-, Mg- and Ca-chlorides. The high salinity fluid has a H2O–NaCl–CaCl2 composition. Blue-to-yellow-green fluorescing hydrocarbon inclusions composed of medium to higher API gravity oils are also identified in some Stages 1 and 2 calcite cements. Stage 1 and 2 calcites have d 18O values between 213.2‰ and 27.2‰ PDB. The lower range of the calculated d 18O values of the ambient fluids (23.5‰ to 1 2.7‰ SMOW) indicate precipitation of these cements from deeply circulating meteoric waters. The presence of petroleum hydrocarbon inclusions in some samples is interpreted to reflect partial mixing with deeper basinal fluids. The paragenetically youngest Stage 3 calcite cement has only been encountered in a fewveins.These calcites are characterised by an intensely zoned luminescence pattern, with bright yellow and non-luminescent zones. Inclusions of Mn-oxides and siliceous sinters are commonly associated with Stage 3 calcite, which is interpreted to have precipitated from shallower meteoric waters. Regional structural analysis revealed that the calcite veins of the Barrandian basin belong to a large-scale system of north–south-trending lineaments that run through the territory of the Czech Republic. The veins probably reflect episodes of fluid migration that occurred along these lineaments during late stages of the Variscan orogeny


Miocene phreatomagmatic volcanism at Tihany (Pannonian Basin, Hungary), 2001, Nemeth K. , Martin U. , Harangi S. ,
A late Miocene (7.56 Ma) maar volcanic complex (Tihany Maar Volcanic Complex - TMVC) is preserved in the Pannonian Basin and is part of the Bakony-Balaton Highland Volcanic Field. Base surge and fallout deposits were formed around maars by phreatomagmatic explosions, caused by interactions between water-saturated sediments and alkali basalt magma carrying peridotite Iherzolite xenoliths as well as pyroxene and olivine megacrysts. Subsequently, nested maars functioned as a sediment trap where deposition built up Gilbert-type delta sequences. At the onset of eruption, magma began to interact with a moderate amount of groundwater in the water-saturated sand. As eruption continued phreatomagmatic blasts excavated downward into limestones, providing access to abundant karst water and deeper to sandstones and schist both providing large amount of fracture-filling water, At the surface, this 'wet' eruption led to the emplacement of massive tuff breccias by fall, surge, mudflow and gravity flow deposition. The nature of the TMVC maar eruptions and their deposits appears to depend on the hydrological condition of the karst and/or fracture-filling aquifer, which varies seasonally with rainfall and spring runoff. The West and East Maar volcanoes of TMVC are interpreted to represent low water input from the karst and/or fracture-filling aquifer ('summer vent'), whereas the East Maar is interpreted to have formed when abundant karst and/or fracture-filling water was available ('spring vent'). (C) 2001 Elsevier Science B.V. All rights reserved

Cave detection and 4-D monitoring: A microgravity case history near the Dead Sea, 2001, Rybakov M. , Goldshmidt V. , Fleischer L. , Rotstein Y. ,

Les archives sdimentaires quaternaires de la grotte sous les Sangles (Bas-Bugey, Jura mridional, France). Indices palo-climatiques et sismo-tectoniques, 2002, Lignier Vincent, Desmet Marc
Quaternary sedimentary archives of the Sous les Sangles Cave (Lower Bugey, Southern Jura, France); paleo-climatic and sismo-tectonic evidences - The Sous les Sangles Cave is located in southern part of Jura mountain at the front part of the northwestern alpine tectonically active massifs. This region was covered by alpine and jurassian glaciers during the Last Glacial Maximum. An old gallery contains stratified fluvial and moraine injection, covered by a 3.5 meters thick deposit of finely laminated silty carbonate and clays. Sedimentological investigation reveals several periods of different water flow depending on glacial and inters glacial periods. The upper finely laminated sediments correspond to the end of the last glacial maximum according to the exokarstic equivalent of the Cerin lake and the U/Th ages obtained with speleothems. Spectral analysis (using Fourier methods and pass-band mapping techniques) on grey-level raw data have been used on the Sous les Sangles sediment. The main result shows evidence of a cyclic deposition according to the three main periodicities recognised through the 1.5-m top sequence. The laminated material is affected by plastic and brittle deformations. The entire deposit is characterised by (1) a vertical faulting without apparent dominant relative movement which can be interpreted as tension faults; (2) an associated soft and brittle deformation similar to thin skin tectonic at centimetre scale affecting the base of the deposit and testified to gravity reworking which could correspond to discrete sismotectonic activity; (3) brittle deformations associated with fluid escape patterns occurring at two specific levels along the vertical faults, emphasising the earth tremor existence according to several broken speleothems. These observations are highly supported by the geodynamic and tectonic frame of this part of Jura massif which reveal an actual uplift of several millimetre/year, especially in this part of the Cluse des Hpitaux cross valley. Numerous historical earthquakes have been documented in this area. The microtectonic study of the cave shows dominant inverse and strike-slip structures correlated to the general tectonic frame.

The engineering classification of karst with respect to the role and influence of caves, 2002, Waltham Tony
The engineering classification of karst defines various complexities of ground conditions, in terms of the hazards that they provide to potential construction. Karst is divided into five classes (from immature to extreme). The three key parameters within the classification are caves (size and extent), sinkholes (abundance and collapse frequency) and rockhead (profile and relief). As one component of karst, caves are a hazard to foundation integrity, though natural surface collapses over caves are extremely rare. A cave roof is normally stable under engineering loading where the roof thickness is greater than 70% of the cave width. Construction can proceed over or around caves that are known. The main difficulty is finding unseen voids; ground investigation in mature karst may require extensive borehole probing, and microgravity is the most useful geophysical technique.

Deep karst conduits, flooding, and sinkholes: lessons for the aggregates industry, 2002, Lolcama J. L. , Cohen H. A. , Tonkin M. J. ,
Limestone aggregate quarries in deeply penetrating karst terrain are often at considerable risk of artesian inflow from groundwater or surface water channeled through the karstic aquifer. The inflow occurs through what are likely to be complex conduits that penetrate hundreds of feet into bedrock. Rates of inflow can exceed the operation's pumping capabilities proving to be uneconomic to manage over the long term. Over time, inflow rates can increase dramatically as turbulent flow through the conduit erodes its soft residual clay-rich fill. One recent investigation observed an inflow rate of more than 40,000 gpm from a surface water source. Floodwater persistently laden with sediment is an indicator of conduit washout and implies increasing inflow rates over time. Conduits carrying floodwater can exist in a variety of forms: along deeply penetrating geologic faults, joints, or following the path of preferentially eroded bedding. Preferential structural deformation along faults or bedding can enhance dissolution during subsequent interaction with groundwater. The resulting conduit may be a complex combination of many geological features, making the exploration and remediation of the pathway difficult. Sinkholes at the site can occur within several contexts. Pre-existing subsidence structures can reactivate and subside further, forming new collapse sinkholes within soil directly overlying the conduit. Cover-collapse sinkhole development can be a direct result of increasing downward groundwater velocities and subsurface erosion associated with the enlargement of a conduit. Normal operation events such as a quarry blast can also provide a significant new linkage between the groundwater and the quarry, allowing rapid drainage of the groundwater reservoir. With such drainage and erosion of karst-fill, sinkholes will develop over localized water table depressions, most significantly over enhanced permeability zones associated with fractures. Paradoxically, although the rise in quarry water level will lead to regional reduction in the hydraulic gradients, on local scales, drainage of the groundwater reservoir increases gradients and leads to the development of cover-collapse sinkholes. Recommended methods for preliminary site investigation can include a detailed review of geological literature and drilling logs to compile a conceptual model of the site. A fracture trace analysis with EM geophysics can confirm the locations of major faults and fractures. Fingerprinting of the various water sources to the quarry and the water in the quarry is an inexpensive and effective means of identifying the source and likely direction of the groundwater and surface water flow. Automated geophysical equipment on the market for performing rapid resistivity and microgravity surveys speeds up the site screening process during reconnaissance exploration for deep structure. It is recommended that mine planning fully incorporate this information so that quarry operators can take proactive measures to avoid catastrophic and costly flooding events. (C) 2002 Elsevier Science B.V. All rights reserved

Integrated high-resolution geophysical investigations as potential tools for water resource investigations in karst terrain, 2002, Mcgrath R. J. , Styles P. , Thomas E. , Neale S. ,
Karstic aquifers can be particularly vulnerable to both pollution from surface activities and large-scale dewatering from mineral winning operations. This is because of the enhanced vertical and lateral flow paths, resulting from the dissolution of carbonate species by rainfall. Often this process results in the development of voids that can range in size from several centimetres to several tens of metres. To date, groundwater vulnerability maps for England and Wales, including karst areas, have been produced using a methodology that does not consider the presence of karst features. The uncertainties that are presented by the potential for pollution by the presence of water-carrying conduits in karst areas, where there are proposed or existing limestone quarries, require new techniques for detecting and delineating underground cave systems. In order for any mapping technique to provide an acceptable assessment of vulnerability, the location and spatial distribution of high permeability flow paths need to be established. Of the available geophysics techniques that may allow for the identification of such features, microgravity and resistivity imaging are likely to be the most successful. Microgravity surveying has the potential to identify the presence and location of such voids, and with the integration of electrical tomographic work, can provide 'targets' for the location of monitoring boreholes. Whilst these techniques are intensive and may not be cost effective on a regional scale, they do have the potential to provide high-resolution data over smaller areas, which would be invaluable to any site or area-specific assessment of vulnerability

Seismic stratigraphy of Late Quaternary deposits from the southwestern Black Sea shelf: evidence for non-catastrophic variations in sea-level during the last ~10[punctuation space]000 yr, 2002, Aksu Ae, Hiscott Rn, Yasar D, Isler Fi, Marsh S,
Detailed interpretation of single channel seismic reflection and Huntec deep-tow boomer and sparker profiles demonstrates that the southwestern Black Sea shelf formed by a protracted shelf-edge progradation since the Miocene-Pliocene. Five seismic-stratigraphic units are recognized. Unit 1 represents the last phase of the progradational history, and was deposited during the last glacial lowstand and Holocene. It is divided into four subunits: Subunit 1A is interpreted as a lowstand systems tract, 1B and 1C are interpreted as a transgressive systems tract, and Subunit 1D is interpreted as a highstand systems tract. The lowstand systems tract deposits consist of overlapping and seaward-prograding shelf-edge wedges deposited during the lowstand and the subsequent initial rise of sea level. These shelf-edge wedges are best developed along the westernmost and easternmost segments of the study area, off the mouths of rivers. The transgressive systems tract deposits consist of a set of shingled, shore-parallel, back-stepping parasequences, deposited during a phase of relatively rapid sea-level rise, and include a number of prograded sediment bodies (including barrier islands, beach deposits) and thin veneers of seismically transparent muds showing onlap onto the flanks of older sedimentary features. A number of radiocarbon dates from gravity cores show that the sedimentary architecture of Unit 1 contain a detailed sedimentary record for the post-glacial sea-level rise along the southwestern Black Sea shelf. These data do not support the catastrophic refilling of the Black Sea by waters from the Mediterranean Sea at 7.1 ka postulated by [Ryan, Pitman, Major, Shimkus, Maskalenko, Jones, Dimitrov, Gorur, Sakinc, Yuce, Mar. Geol. 138 (1997) 119-126], [Ryan, Pitman, Touchstone Book (1999) 319 pp.], and [Ballard, Coleman, Rosenberg, Mar. Geol. 170 (2000) 253-261]

Late Quaternary history of the Marmara Sea and Black Sea from high-resolution seismic and gravity-core studies, 2002, Hiscott R. N. , Aksu A. E. ,
Lithologic and multi-proxy paleoenvironmental data from 21 dated cores have been used to define three allostratigraphic units (allounits) within the late Quaternary successions of the Marmara Sea and Black Sea. Allounits are bounded by unconformities and their correlative conformities. In both regions, Allounit A extends from the seafloor downward to a ~12-11-ka sequence boundary, which is a major shelf-crossing unconformity in water depths less than ~100-110 m. In deep basins of the Marmara Sea, the lower part of Allounit A, designated Subunit A2, is a laminated sapropel, M1. On the shelf, Subunit A2 consists of backstepping delta lobes and early-transgressive barrier islands and sand sheets. Allounit B has only been recovered in Marmara Sea cores collected at water depths greater than ~90 m, and represents basinal or prodeltaic deposition during the 23-12-ka late Pleistocene lowstand. During the last glacial maximum, the shelves surrounding the Marmara Sea were subaerially exposed, and deltas of Allounit B accumulated along the present-day shelf edge. Following the post-glacial rise of global sea level to -75 m at ~12 ka, the Marmara Sea quickly became inundated and thereafter rose in synchroneity with the Mediterranean. By ~10 ka, the Black Sea rose to start spilling into the Marmara Sea, leading to establishment of a brackish-water lid that has persisted to the modern day. The strongest Black Sea outflow began at ~10 ka and persisted to ~6 ka, promoting the accumulation of sapropel M1 in the deep Marmara Sea, and progradation of an overflow delta just south of the exit from the Bosphorus Strait. Allounit C is a laminated sapropel (M2) in basinal cores, dated at ~30-23 ka. Like M1, it is believed that M2 accumulated during a period of increased brackish-water input into the Marmara Sea mainly from the Black Sea. In the Black Sea, wave erosion kept the shelf stripped of unconsolidated sediments during the falling sea level associated with the last glaciation and subsequent early stages of the post-glacial Holocene transgression. This erosion created a major unconformity, [alpha]. Shelf-edge deltas of Allounit B received their sediment during the last lowstand from small rivers that likely coalesced into a single system toward the shelf edge, at modern water depths of -100 to -110 m. These deltas were active until ~11-10.5 ka. Subsequently, sea level in the Black Sea rose to -40 m by ~10 ka, and a set of backstepping barrier islands developed on the shelf as part of the associated transgressive systems tract. Once water level reached -40 m, continued sea-level rise stalled until ~9 ka as the Black Sea began to spill across the Bosphorus Strait into the Marmara Sea

Karst collapse related to over-pumping and a criterion for its stability, 2003, He K. Q. , Liu C. L. , Wang S. J. ,
Karst collapse, caused by natural or artificial abstraction of groundwater, has been an environmental geological problem. The origin of karst collapse has been described by the potential erosion theory and the vacuum absorption erosion theory. However, a mathematical prediction criterion for karst collapse cannot be established by these two theories. This paper, from a new perspective, attempts to explain the microcosmic mechanism of karst collapse on the basis of these two theories. At a certain point in the unconsolidated soil covered on karst caves, when shearing stress surpasses shear strength of the soil, it fails under the mechanic effects of water and gas as well as gravity pressure. With an increase in damage points, a break plane appears and the soil overlying the karst caves is completely damaged and, thus, the ground surface collapses. On the basis of Mohr-Coulomb damage theory and previous studies, a prediction criterion of karst collapse is presented. An example displays the calculating process of the model and proves its reliability by analyzing nine typical collapses caused by a pumping test in Guizhou Province, China

The application of Time-Lapse Microgravity for the Investigation and Monitoring of Subsidence at Northwich, Cheshire, 2003, Branston Mw, Styles P,
Peter Street is an area of terraced houses in Northwich suffering from subsidence, thought to be related to salt extraction in the 19th century. Microgravity and resistivity profiling have been used as non-invasive techniques to investigate the cause of this subsidence. Repeat (or time-lapse) microgravity has been used to assess the stability and evolution of the low-density areas. Time-lapse microgravity uses the characteristics of anomaly size and gradient to track the development of cavities as they propagate to the surface. It is possible to monitor the change in gravity with time and to model the increase in cavity volume and/or depth. A gravity low was found to be coincident with the area experiencing subsidence. Integratedmodelling techniques including Euler deconvolution, Cordell & Henderson inversion and GRAVMAG modelling have been used to investigate the depth and size of the body responsible for this anomaly. Resistivity imaging has been used to investigate the conductivity of the near surface and constrain the gravity models. Results from both techniques suggest that low density ground is now present at a depth of 3-4 m below the surface in the subsidence affected area. The use of time-lapse microgravity has shown that there has been an upwardmigration of a low-density zone at gravity anomaly C over the monitoring period

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