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 ground-water travel time is 1. the time-required for ground water to travel between two locations [22]. 2. the time required for a unit volume of ground water to travel between two locations. the travel time is the length of the flow path divided by the velocity, where velocity is the average ground-water flux passing through the cross-sectional area of the geologic medium through which flow occurs, perpendicular to the flow direction, divided by the effective porosity along the flow path. if discrete segments of the flow path have different hydrologic properties, the total travel time will be the sum of the travel times for each discrete segment [22].?
The basic textbooks and reference sources in speleology (Kunsky, 1954; Trombe, 1952 and Warwick, 1962) describe the process of solution of carbonate rocks in terms of the system CaCO3 - H20 - CO2, making little or no reference to the role of MgCO3 in the solution process. The widespread occurrence of dolomitic rocks amongst the older sedimentary formations of Australia, e.g., at Buchan, Victoria, and Camooweal, Queensland, makes some knowledge of the complexity of solution processes in rocks containing dolomite highly desirable for the understanding of the development of caves in this continent. This paper is intended to review the scattered literature on this topic and to describe what is known of the behaviour of the system CaO - Mg0 - CO2 - H20.
Mixtures of two saturated H2O/1bCO2/1bCaCO3 solutions of different chemical composition gain renewed capability of dissolving calcite. This is an important mechanism in the solution processes of limestone during karstification. Using recent data on the kinetics of calcite dissolution, dissolution rates in mixture corrosion are calculated. In the region of the chemical composition of natural karst waters the solution rate is approximated by:R=-[alpha]([Ca2] - [Ca2]s where [Ca2], [Ca2]s are the concentrations of the Ca2 ion in the solution and at saturation, respectively. [alpha] ranges from 10-4 to 3[middle dot]10-4 cm s-1.This result is applied to the solution of limestone in karst water mixtures flowing in cylindrical conduits. The saturation length, i.e. the length xs which the solution has to travel to drop to 37% of its renewed dissolving capability, is calculated in the region of turbulent flow. This region starts at conduit radii R of several millimeters. At the onset of turbulent flow the saturation length is 260 m, increasing with R1.665. The increase of conduit radii is calculated from the dissolution rates of calcite solution to be on the order of 10-3 cm yr.-1.The results are discussed for a comprehensive model of karstification and cave development, which for the first time gives a realistic theoretical time region for cave development, in agreement to experience
Trials of the method of estimating the aggressiveness of karst water by artificial saturation (Stenner, 1969) were made on stream and spring waters in limestone country at Buchan, Victoria. Saturation was brought about with both laboratory reagent grade calcium carbonate and also with powdered local limestone. Resulting estimates of the initial degree of saturation varied considerably. The differences amounted to an average 5.6% (maximum 8.0%) in aggressiveness estimated from change in total hardness, 8.8% (maximum 14.0%) using calcium hardness, and 9.4% (maximum 31.0%) using magnesium hardness. Whilst the average difference between the two sets of results are not great, and certainly do not prohibit the use of the original Stenner method, they do serve to indicate that in particular individual cases misleading results can be obtained if local limestone is not used. Possible reasons for the differing behaviour of the two materials is suggested.
A large conduit spring issuing from Cretaceous limestones in Belize, Central America, displays a positive relation of discharge to solute concentration. Beneath a maturely-dissected cockpit karst, the hydrologic system combines allogenic surface water from an invasion polje with authigenic karst water. Dynamic mixing produces three climatically-induced discharge phases: baseflow, normal, and high-stage flow. Each has an associated hydrochemical regime, predominantly diffuse-flow karst water. An areal solute concentration of ~80 mg l-1 Ca2 is estimated, with a “denudation rate” of 100 mm per 1000 yr
CAVES IN THE SOFT COVER OF THE PLATEAUX DU NIVERNAIS (NIEVRE, FRANCE) - North of the Massif Central, around Nevers, the jurassic limestones are covered with a mio-pliocene silt mantle characterised by different caves: collapse dolines in relation with the crypto-karst situated into the underlying limestones and little holes developing in the silt mass (ex.: ponor of Bois de la Grange, length: 11 m). The tertiary mantle and the forests take a prominent part in the regulation and the physico-chemistry of karst waters.
Detailed chemical and physical analyses are presented for 42 karst waters (springs, groundwater) sampled in the Kimberley region in northern Western Australia (Devonian Reef complex) during May '88. A general pattern of physical and chemical effects (e.g. tufa deposition) was found.
