Deprecated: Function get_magic_quotes_gpc() is deprecated in /home/isthin5/public_html/addon-domains/speleogenesis.info/template/toolbar_right.php on line 7
Search KARSTBASE:
Search in KarstBase
Numerous shells of molluscs were found in loamy sediments rich in limestone and dolomite scree filling small karst forms and forming debris fans. They have been analysed from several logs in the Tatra Mountains. Woodland and open-country snails are the main components of fauna. Relations between two mentioned ecological groups of molluscs indicate climatic changes and moving the timberline. Three phases of warming separated by two stages of the colder climate were recognised. They can be related to following ages: XIII and first half of XIV centuries AD (warm phase), second half of XIV - XVII centuries AD (cold phase), XVIII and the first half of XIX centuries (warm phase), second half of the XIX century (cold phase) and finally to XX century (warm phase).
Since 2003, an extensive hydrogeological investigation has been carried out on Monte Baldo, in order to make a census of springs occurring along the west side of the mountain and to evaluate the quality of their water. The investigation included morphological and hydrogeological observations concerning the Tanella cave and interdisciplinary investigations performed on the deposits found in the cave. This paper shows the first data concerning the hydrogeology of the cave, as well as data on stratigraphy, pollen and micro-charcoals obtained from the analyses of a well preserved sequence located at ca. 80 m from the entrance (sequence A). The aim of the study was to reconstruct the environment of the area around the cave along the time span testified by the sequence. The sequence is 60 cm thick and was built up by fluvioglacial sediments followed by lacustrine sediments. Five samples taken along the sequence plus three recent control samples (mosses), collected in places assumed as origins of the pollen input, were studied for pollen and micro-charcoals. Pollen preservation was good and concentration varied from 101 to 103 p/g. Pollen spectra from the cave showed the evolution from a landscape of alpine grassland above the timberline, likely of glacial age, to a more forested Holocene landscape similar in flora to the current one testified by the control samples. Pollen probably arrived in the cave by air, water and animals and from plants growing near the cave. It appears to have been continuously underwater after its deposition due to its very good state of preservation. Micro-charcoals suggested that fires were sometimes lit near the cave.
The Judbarra / Gregory Karst Region is situated in the Judbarra / Gregory National Park, west of Timber Creek, Northern Territory. Several large joint controlled maze caves occur within the area, developed within and below a prominent dolomitic layer (the Supplejack Member). The caves are predominantly shallow in depth (< 15 m below the surface) but are occasionally developed deeper as multi-level systems, reaching the aquifer. Two biological surveys from the largest caves have revealed 56 morphospecies from 43 families, 19 orders, and 7 classes. All collecting was undertaken in the northern dry season (April to September) and consisted predominantly of opportunistic collecting. The diversity of invertebrates collected from the Judbarra / Gregory karst comprised non-troglobionts (48 species, 86%), troglobionts (5 species, 9%), stygobionts (2 species, 3%), and trogloxenes (1 species, 2%). Five of the species are considered to be potential troglobionts, and two potential stygobionts as indicated by troglomorphisms such as elongate appendages and reduced or absent eyes. The five troglobiont species are an isopod (Platyarthridae: Trichorhina sp.), a scorpion (Buthidae: Lychas? sp. nov.), a pseudoscorpion (Geogarypidae: Geogarypus sp. nov.), a millipede (Polydesmida: sp.), and a planthopper (Meenoplidae: sp.). The two stygobiont species are a hydrobiid snail (Hydrobiidae: sp.), and an amphipod (Amphipoda: sp.). The troglobiont scorpion is only the second collected from a cave environment from continental Australia.
Bare Mountain is an isolated complex of mountain peaks Southeast of the town of Beatty in southern Nevada. This small mountain range is located between the alluvial basins of Crater Flat to the East and the northern Amargosa Desert to the Southwest. The range is built of a folded and complexly faulted, generally northward-dipping sequence of weakly to moderately metamorphosed upper Proterozoic and Paleozoic marine rocks. Along the eastern and northern margins of Bare Mountain there are four clusters of Ag-Hg-fluorite deposits from which pipe-like breccia bodies have been reported in the literature. One of these deposits, the Diamond Queen Mine (aka Goldspar Mine; 36°50.4’ N, 116°38.3’ W) was prospected for gold and mined for fluorspar. The age of the mineralization is younger than 12.9±0.4 Ma (according to K/Ar dates of replacement adularia). During our visit in 2010 we observed solutional cavities in the open-pit works of the mine carved in the dolomite of the Cambrian Nopah Formation. The cavities have dimensions of a few meters to tens of meters. Their inner surfaces are smooth and barren. The morphology of the cavities strongly suggests dissolution under phreatic conditions. Cavities are filled with buff-colored clay material containing bands of black to dark-violet to yellow- green to colorless fluorite. Fluid inclusions in the Diamond Queen fluorite yielded homogenization temperatures of ca. 130°C. We measured the δD of the fluid inclusion water in this fluorite and compared them to δD values measured in scalenohedral calcite from the Sterling Mine (Au) located 1.5 km to the north. Isotopic values are remarkably similar: δD = -100±2 ‰ (n = 6). Despite the fact that the analyzed water was derived from hypogene, hydrothermal minerals these isotopic values bear a paleoclimatological significance. This is because according to the currently accepted model, the Au-Hg-fluorite deposits at Bare Mountain owe their existence to the circulation of meteoric water triggered by emplacement of the silicic magma chamber under the Timber Mountain-Oasis Valley caldera some 15 km to the north. The Late Miocene meteoric- hydrothermal water is isotopically similar to the modern-day precipitation (-106 to -92 ‰). Between ca. 1.5 and 2.5 Ma the δD values of meteoric water in the area were substantially less negative (-70 to -50 ‰) and then gradually decreased to modern values. Knowledge regarding hypogene karst associated with the epithermal ore deposits in Nevada is limited. In north-central Nevada, post-ore hypogene dissolution, brecciation and mineralization occurred at some of the Carlin Trend deposits at ca. 2 Ma. In contrast, hypogene karst was a preore process at Diamond Queen; it has played a role in creating the ore-bearing structure.