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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. ...
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,
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. ...
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 well is 1. a shaft or hole sunk into the earth to obtain water, oil, gas, or minerals [10]. 2. a deep vertical rounded hole or shaft in the floor of a cave or at the bottom of a closed depression [10]. 3. a bored, drilled or driven shaft, or a dug hole, whose depth is greater than the largest surface dimension [22].?
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KarstBase a bibliography database in karst and cave science.
Featured articles from Cave & Karst Science Journals
China has the worlds largest proven gypsum (CaSO4.2H2O) resources in the world. The gypsum ranges from pre-Cambrian to Quaternary in age and occurs in varied geological environments. The rapid dissolution rate of gypsum means that gypsum karst development can be very fast, resulting in progressively worsening geohazards. This paper reviews the characteristics of the gypsum deposits and their associated geohazards in China.Three kinds of gypsum karst are discussed. These include karst in massive thick beds of gypsum, karst in thin-bedded gypsum and compound karst in gypsum and carbonate rocks. Some site-specific problems are also examined. In the Shanxi coalfield, breccia pipes, or collapse columns, caused by the dissolution of Ordovician gypsum, penetrate the overlying Carboniferous and Permian coal-bearing sequences resulting in difficult coal mining conditions. In Guizhou Province re-activated gypsum karst is associated with leakage of water through the gypsum from a reservoir. Remedial engineering works have been carried out, but leakage still occurs. Groundwater abstraction from gypsiferous sequences is also problematical. It can yield sulphate-polluted water and cause subsidence problems both through gypsum dissolution and groundwater drawdown.
The rapid underground dissolution of gypsum, and the evolution of the gypsum karst in Lithuania and England, results in subsidence problems which can make construction difficult. The natural dissolution yields sulphate-rich groundwater of poor quality and the karst is susceptible to the rapid transmission of pollutants. In the north of Lithuania gypsum karst is developed in Devonian gypsum. Here the towns of Birai, Pasvalys and the surrounding countryside suffer subsidence and some buildings have been damaged. The majority of the potable water in these areas is derived from groundwater extracted from sandstone sequences that underlie the gypsum. In Lithuania conservation measures have been introduced to control agriculture and prevent pollution of the gypsum karst. These measures include environmentally-friendly farming, restrictions on land use and exclusion zones around subsidence hollows. In England subsidence caused by the dissolution of Permian gypsum has caused severe problems in the vicinity of the town of Ripen. Numerous buildings have been damaged and new sites are difficult to develop. Here formal planning regulations have recently been introduced to help to protect against the worst effects of subsidence resulting from gypsum dissolution. (C) 1999 Elsevier Science B.V. All rights reserved
The main kinds of evaporite karst, both sulphate karst and halide karst, are widely distributed in China. Gypsum karst is especially widespread, because China contains the largest gypsum resources in the world. These gypsum deposits range in age from Precambrian to Quaternary, and they were deposited in many environments, including marine, lacustrine, thermal process, metamorphic, and also as secondary deposits. Halide karst is developed in rock salt and salt-water lakes, the latter related to more than 300 salt-water lakes distributed in the Qinghai Plateau of Xizang (Tibet) province. Gypsum and halite are easily dissolved; therefore, development of evaporite karst is somewhat different when compared with carbonate karst, which has developed many typical features in China. This paper discusses the mechanism and development of evaporite karst in sulphate rocks and in halides, and makes comparisons between evaporite karst and carbonate karst based upon field investigations and new tests in the laboratory. The geohazards of evaporite karst usually are triggered by natural karst processes, but often they are exaggerated by artificial (human) actions and engineering impacts that cause flesh groundwater or surface water to come in contact with the evaporite rocks. Some examples of evaporite-karst geohazards are described in this paper; they are present in Shandong, Sichuan, and Guizhou Provinces, and in the Qinghai Plateau of China
Geohazards related to chalk coastal cliffs from Eastbourne to Brighton, Sussex are described. An eight-fold hazard classification is introduced that recognizes the influence of chalk lithology, overlying sediments and weathering processes on location, magnitude and frequency of cliff collapses. Parts of the coast are characterized by cliffs of predominantly a single chalk formation (e.g. Seven Sisters) and other sections are more complex containing several Chalk formations (Beachy Head). Rock properties (intact dry density or porosity) and mass structure vary with each formation and control cliff failure mechanisms and scales of failures. The Holywell Nodular Chalk, New Pit Chalk and Newhaven Chalk formations are characterized by steeply inclined conjugate sets of joints which lead to predominantly plane and wedge failures. However, the dihedral angle of the shears, the fracture roughness and fill is different in each of these formations leading to different rock mass shear strengths. In contrast the Seaford and Culver Chalk formations are characterized by low-density chalks with predominantly clean, vertical joint sets, more closely spaced than in the other formations. Cliff failure types range from simple joint controlled conventional plane and wedge failures to complex cliff collapses and major rock falls (partial flow-slides) involving material failure as well as interaction with discontinuities. Other hazards, related to sediments capping the Chalk cliffs, include mud-slides and sandstone collapses at Newhaven, and progressive failure of Quaternary Head and other valley-fill deposits. Weathering, including the concentration of groundwater flow down dissolution pipes and primary discontinuities, is a major factor on rate and location of cliff collapses. A particular feature of the Chalk cliffs is the influence of folding on cliff stability, especially at Beachy Head, Seaford Head and Newhaven. A new classification for cliff collapses and a new scale of magnitude for collapses are introduced and used to identify, semi-quantify and map the different hazards. Climate (and climate change) and marine erosion affect the rate of development of cliff collapse and cliff-line retreat. This was particularly evident during the wet winters of 1999-2000-2001 when the first major collapses along protected sections of coastline occurred (Peacehaven Cliffs protected by an undercliff wall; Black Rock Marina the Chalk cliffs and the Quaternary Head). It is the geology, however, that controls the location and scale of erosion and cliff failure
On a world scale, the dissolution of limestone and gypsum by natural waters creates extensive karst landforms that can be very difficult ground for civil engineers. Caves threaten foundation integrity, notably where their width is greater than their roof thickness. Sinkholes pose many problems, and are classified into six types, including subsidence sinkholes formed in soil cover within karst terrains. Rockhead morphology varies from uniform to pinnacled, also creating difficult ground to excavate or found upon. A proposed engineering classification of karst defines various complexities of ground conditions by the geohazards that they provide, mainly the caves, sinkholes and rockhead relief. Ground investigation techniques and foundation design philosophies are considered so that they are appropriate to the ground conditions provided by the different classes of karst.
