Community news

Speleology in Kazakhstan

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

New publications on hypogene speleogenesis

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

The deepest terrestrial animal

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

Caves - landscapes without light

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

Did you know?

That crescentic wall niche is see meander niche.?

Checkout all 2699 terms in the KarstBase Glossary of Karst and Cave Terms

What is Karstbase?

Search KARSTBASE:

keyword
author

Browse Speleogenesis Issues:

KarstBase a bibliography database in karst and cave science.

Featured articles from Cave & Karst Science Journals
Chemistry and Karst, White, William B.
See all featured articles
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;
See all featured articles from other geoscience journals

Search in KarstBase

Your search for stability (Keyword) returned 101 results for the whole karstbase:
Showing 91 to 101 of 101
Solution Caves in Regions of Moderate Relief, 2012, Palmer, Arthur N.

Caves in regions of moderate relief are widely regarded as the standard to which all others are compared. Tectonic stability is their most significant characteristic. The presence of moderate relief implies that uplift of the land is slow and erosional processes are able to keep pace. As a result, rivers easily erode to their local base levels, and base-level control is reflected in cave passages. The relation between caves and regional geomorphic history is stronger than in any other setting. Examples are given from the Illinois Basin (Kentucky and Indiana), the Ozark Plateau (Missouri), and the Appalachians.


Speleothem deposition at the glaciation threshold An attempt to constrain the age and paleoenvironmental significance of a detrital-rich flowstone sequence from Entrische Kirche Cave (Austria), 2012, Meyer M. C. , Sptl Ch. , Mangini A. , Tessadri R.

Proxy records from high-altitude locations predating the Last Glacial Maximum are rare but could provide invaluable insights into the response of alpine catchments to the rapid climate fluctuations which characterized the last glacial period. Herewe present a detrital-rich flowstone record from Entrische Kirche Cave, an inneralpine cave situated close to the accumulation area of the Pleistocene ice-stream network of the European Alps that expanded repeatedly into the lowlands during glacial maxima. U–Th dating of this calcite is challenging due to high detrital Th. However, petrographic and stable isotope analyses in conjunction with associated clastic cave sediments provide useful insights into the climatic boundary conditions during speleothem formation and into the paleoenvironmental processes which operated in the ~2000 m-high catchment above the cave. Our data show that millennial-scale temperature fluctuations had a first-order control on the periglacial activity and vegetation in the catchmentwhich strongly influenced the formation and infiltration of detritus into the karst aquifer. The brown laminated and brown dendritic fabrics that compose much of the detrital-rich flowstone succession reflect these environmental processes. The temperature-dependence of periglacial and permafrost processes allows to constrain the amount of cooling relative to the present-day mean annual air temperature that is required to initiate detrital-rich calcite formation in Entrische Kirche Cave, i.e. −2.5 °C (minimum) to −6 °C (maximum), respectively. White inclusion-poor calcite that is intercalated with the detrital-rich calcite indicates warm (interstadial) conditions and geomorphological stability in the catchment area. One such phase has been U–Th dated to 88.3±6.9 ka (i.e. Greenland Interstadial 21 or 22). 


Forum Correspondence: Strength and stability of calcite stalactites, 2012, Waltham, Tony

Emine-Bair-Khosar Cave in the Crimea, a huge bone accumulation of Late Pleistocene fauna, 2013, Ridush . , Stefaniak K. , Socha P. , Proskurnyak Y. , Marciszak A. , Vremir M. , Nadachowski A.

The Crimean Mountains are well known from the abundance of Middle and Late Palaeolithic sites and palaeontological remains recovered from cultural layers in caves and rockshelters. The fossil-bearing deposits of Emine-Bair-Khosar Cave, located at the elevation of 1000 m on the Chatyrdag Plateau, yielded a very diverse and numerous vertebrate remains that widen the knowledge of Late Pleistocene faunal diversity in the Crimea. The assemblage comprised in total almost 50 species of vertebrates. Studies included geomorphological, geological and stratigraphic analyses as well AMS 14C dating. Faunal remains were present in ten palaeontological sites. The main bone accumulation (section Ba2) was deposited during Middle Valdai or Vytachiv (MIS 3) interstadial, and including a long time gap, to the end of the Pleistocene and the Holocene. Comparison of the Emine-Bair-Khosar fauna with vertebrate faunas of other Crimean sites showed a remarkable stability in the faunal composition and frequency during the whole MIS 3 interstadial. Steppe and other open-country species dominated in the compared assemblages, while boreal-tundra species were far less numerous. Inhabitants of forests, including red deer and some rodents, were stable members of fossil assemblages.


Rapidcreekite in the sulfuric acid weathering environment of Diana Cave, Romania, 2013, Onac B. P. Effenberger H. S. Wynn J. G. Povară, I.

The Diana Cave in SW Romania develops along a fault line and hosts a spring of hot (Tavg = 51 °C), sulfate-rich, sodium-calcium-chloride bearing water of near-neutral pH. Abundant steam and H2S rises from the thermal water to condensate on the walls and ceiling of the cave. The sulfuric acid produced by H2S oxidation/hydrolysis causes a strong acid-sulfate weathering of the cave bedrock generating a sulfate-dominated mineral assemblage that includes rapidcreekite, Ca2(SO4)(CO3)•4H2O closely associated with gypsum and halotrichite group minerals. Rapidcreekite forms bundles of colorless tabular orthorhombic crystals elongated along [001] and reaching up to 1.5 mm in length. For verifying the hydrogen bond scheme and obtaining crystal-chemical details of the carbonate group a single-crystal structure refinement of rapidcreekite was performed. Its unit-cell parameters are: a = 15.524(2), b = 19.218(3), c = 6.161(1) Å; V = 1838.1(5) Å3, Z = 8, space group Pcnb. Chemi¬cal composition (wt%): CaO 35.65, SO3 24.97, CO2 13.7, H2O 23.9, Na2O 0.291, MgO 0.173, Al2O3 0.07, total 98.75%. The empirical formula, based on 7 non-water O atoms pfu, is: Ca1.98Na0.029Mg0.013 Al0.004(S0.971 O4)(C0.97O3)•4.13H2O. The d34S and d18O values of rapidcreekite and other cave sulfates range from 18 to 19.5‰ CDT and from –9.7 to 7.8‰ SMOW, respectively, indicating that the source of sulfur is a marine evaporite and that during hydration of the minerals it has been an abundant 18O exchange with percolating water but almost no oxygen is derived from O2(aq). This is the first descrip¬tion of rapidcreekite from a cave environment and one of the very few natural occurrences worldwide. We also report on the mineral stability and solubility, parameters considered critical to understand the co-precipitation of carbonates and sulfates, a process that has wide applications in cement industry and scaling prevention.


Karst Sinkholes Stability Assessment in Cheria Area, NE Algeria, 2013, Yacine Azizi, Med. Ridha Menani, Med Laid Hemila, Abderahmane Boumezbeur

 

Karst; Rock Mass Rating (RMR);Sinkhole collapse; Tebessa This research work deals with the problem of karst sinkhole collapse occurring in the last few years in Cheria area (NE Algeria). This newly revealed phenomenon is of a major constrain in land use planning and urbanization, it has become necessary to locate and assess the stability of these underground features before any planning operation. Several exploration methods for the localization of underground cavities have been considered. Geological survey, discontinuity analysis, resistivity survey [ground penetrating radar has not been used as most of the Mio-Plio-Quaternary filling deposit covering Eocene limestone contains clay layers which limits the applicability of the method (Roth et al. in Eng Geol 65:225–232, 2002)] and borehole drilling were undertaken in order to locate underground cavities and assess their depth, geometry, dimensions, etc. Laboratory testing and field work were also undertaken in order to determine both intact rock and rock mass properties. All the rock mechanics testing and measurement were undertaken according to the ISRM recommendations. It has been found that under imposed loading, the stability of the karst cavities depends on the geo-mechanical parameters (RMR, Rock Mass Rating; GSI, Geological Strength Index; E, Young modulus) of the host rock as well as the depth and dimensions of the gallery. It increases with RMR, GSI, E and depth and decreases as the cavity becomes wider. Furthermore, the calculation results show that a ratio (roof thickness to gallery width) of 0.3 and more indicate, a stable conditions. The results obtained in this work allow identifying and assessing the stability of underground karst cavities. The methodology followed in this paper can be taken as a road map in the establishment of a hazard map related to the studied phenomenon. This map will be a useful tool for the future urban extension planning in Cheria area.


Radon, carbon dioxide and fault displacements in central Europe related to the Tohoku Earthquake, 2014, Briestensky Milos, Thinova Lenka, Praksova Renata, Stemberk Josef, Rowberry Matt D. , Knejflova Zuzana

Tectonic instability may be measured directly using extensometers installed across active faults or it may be indicated by anomalous natural gas concentrations in the vicinity of active faults. This paper presents the results of fault displacement monitoring at two sites in the Bohemian Massif and Western Carpathians. These data have been supplemented by radon monitoring in Mladec Caves and by carbon dioxide monitoring in Zbrasov Aragonite Caves. A significant period of tectonic instability is indicated by changes in the fault displacement trends and by anomalous radon and carbon dioxide concentrations. This was recorded around the time of the catastrophic MW = 9.0 Tohoku Earthquake which hit eastern Japan on 11 March 2011. It is tentatively suggested that the Tohoku Earthquake in the Pacific Ocean and the unusual geodynamic activity recorded in the Bohemian Massif and Western Carpathians both reflect contemporaneous global tectonic changes.


A review on natural and human-induced hazards and impacts in karst, 2014, Gutiérrez Francisco, Parise Mario, De Waele Jo, Jourde Hervé

Karst environments are characterized by distinctive landforms related to dissolution and a dominant subsurface drainage. The direct connection between the surface and the underlying high permeability aquifers makes karst aquifers extremely vulnerable to pollution. A high percentage of the world population depends on these water resources. Moreover, karst terrains, frequently underlain by cavernous carbonate and/or evaporite rocks, may be affected by severe ground instability problems. Impacts and hazards associatedwith karst are rapidly increasing as development expands upon these areas without proper planning taking into account the peculiarities of these environments. This has led to an escalation of karst-related environmental and engineering problems such as sinkholes, floods involving highly transmissive aquifers, and landslides developed on rocks weakened by karstification. The environmental fragility of karst settings, togetherwith their endemic hazardous processes, have received an increasing attention from the scientific community in the last decades. Concurrently, the interest of planners and decision-makers on a safe and sustainable management of karst lands is also growing. This work reviews the main natural and human-induced hazards characteristic of karst environments, with specific focus on sinkholes, floods and slope movements, and summarizes the main outcomes reached by karst scientists regarding the assessment of environmental impacts and their mitigation.


Incipient vertical traction carpets within collapsed sinkhole fills, 2014,

Small vertically oriented traction carpets are reported from the collapsed sandy fills of 100 m deep Devonian limestone sinkholes underlying the Lower Cretaceous Athabasca oil sands deposit in north-eastern Alberta, Western Canada. Dissolution of 100 m of underlying halite salt beds caused cataclysmic collapse of the sinkhole floors and water saturated sinkhole sand fills to descend very rapidly. Turbulent currents flushed upper sinkhole fills of friable sandstone blocks and disaggregated sand and quartz pebble for tens of metres. Laminar deposits with inverse grading accumulated as many as six to eight curvilinear entrained pebble streaks, 10 to 30 cm long, vertically impinged against the sides of descending collapse blocks. These deposits were initiated as vertically oriented early stage traction carpets that interlocked fine sand grains and inversely graded overlying pebbles entrained below the dilute overlying turbulent flows. Vortexes that flushed these sinkhole fills and induced these depositional processes may have lasted only seconds before the very rapid descents abruptly halted. Some of the fabrics were suspended vertically in-place and preserved from unlocking and obliteration. These small fabrics provide insight into the instability and ephemeral character of the transition from strong gravity-driven grain falls to very early stages of traction carpet formation. These short-lived deposits of very thin sand layers resulted from sufficient incipient frictional freezing that grain interlocking overcame, however briefly, the strong gravity drives of the vertical falls that would have otherwise dispersed grains and obliterated any organized fabric patterns. Tenuous frictionally locked grains were also suspended at the centres of hyperbolic grain fall flows that briefly developed between turbulent flow eddies, some of which were fortuitously preserved. Some of these suspended grain locking zones passed downward onto the relatively more stable surfaces of the rapidly descending block surfaces. The morphogenesis of these early stage traction carpets differ from more fully developed deposits elsewhere because of their short-lived transport, dynamic instability and vertical orientation.


A new method to quantify carbonate rock weathering, 2015, Dubois Caroline, Deceuster John, Kaufmann Olivier, Rowberry Matt D.

The structure and composition of carbonate rocks is modified greatly when they are subjected to phenomena that lead to their weathering. These processes result in the production of residual alterite whose petrophysical, mechanical, and hydrological properties differ completely to those of the unweathered rock. From a geotechnical perspective, it is important that such changes are fully understood as they affect reservoir behavior and rock mass stability. This paper presents a quantitative method of calculating a weathering index for carbonate rock samples based on a range of petrophysical models. In total, four models are proposed, each of which incorporates one or more of the processes involved in carbonate rock weathering (calcite dissolution, gravitational compaction, and the incorporation of inputs). The selected weathering processes are defined for each model along with theoretical laws that describe the development of the rock properties. Based on these laws, common properties such as rock density, porosity, and calcite carbonate content are estimated from the specific carbonate rock weathering index of the model. The propagation of measurement uncertainties through the calculations has been computed for each model in order to estimate their effects on the calculated weathering index. A new methodology is then proposed to determine the weathering index for carbonate rock samples taken from across a weathered feature and to constrain the most probable weathering scenario. This protocol is applied to a field dataset to illustrate how these petrophysical models can be used to quantify the weathering and to better understand the underlying weathering processes.


Characterization of minothems at Libiola (NW Italy): morphological, mineralogical, and geochemical study, 2016, Carbone Cristina, Dinelli Enrico, De Waele Jo

The aim of this study is to characterize in detail, the mineralogy of different-shaped concretions as well as to investigate the physico-chemical parameters of the associated mine drainage and drip waters in the Santa Barbara level of the Libiola Mine (NW Italy) by several geochemical and mineralogical techniques. Under the term “minothems” we are grouping all those secondary minerals that occur under certain form or shape related to the conditions under which they formed but occur in a mine, or in any artificial underground environment (i.e., "mine speleothems"). Different types of minothems (soda straw stalactites, stalactites, and draperies) were sampled and analyzed. Mineralogical results showed that all the samples of stalactites, stalagmite and draperies are characterized by poorly crystalline goethite. There are significant differences either in their texture and chemistry. Stalactites are enriched in Zn, Cd, and Co in respect to other minothems and show botryoidal textures; some of these exhibit a concentric layering marked by the alternation of botryoidal and fibrous-radiating textures; the draperies are enriched in V and show aggregates of sub-spheroidal goethite forming compact mosaic textures. Geochemical investigations show that the composition and physico-chemical parameters of mine drainage and drip waters are different from the other acidic mine water occurrences in different areas of the Libiola Mine, where minothems are less abundant. All mine water samples contain Cu, Ni, and Zn in appreciable levels, and the physico-chemical conditions are consistent with the stability of ferrihydrite, which however tends to transform into goethite upon ageing.


Results 91 to 101 of 101
You probably didn't submit anything to search for