441 research outputs found
On the Karst Ecosystem
No full textIn this paper the author gives a definition of the karst ecosystem and discusses the characteristics of the karst environment and karst ecosystem and the relationship between life and the karst environment. Finally he clarifies the structure, driving force and functions of the karst system
A SEM analysis of quartz grains in the sediments of the Lhasa karst areas, Tibet
No full textThe quartz grains from the sediments of the Lhasa karst areas have been examined by scanning electron microscopy. As the quartz grains were chosen from newly-discovered sediments in caves and relict karst doline, the results show some differences from the sediments sampled by the author in 1987, which were examined by Bull and others (1990). The grains from cave alluvial deposits and doline sediments show many features that are only produced in high chemical and water energy environments. These include solution grooves, holes and V pits. The cave sediments were deposited in the Pleistocene, according to the U-series dating. The analysis, however, shows that the grains might come from the sediments of the Tertiary surface of the plateau, which were brought into the caves by water, mixed with fresh weathering materials and then redeposited. The destruction of this Tertiary surface by intensive erosion was induced by the fast uplift in the Quaternary. Alternatively, many features had also been modified in the chemically active periods during the Quaternary.link_to_subscribed_fulltex
Using continuous electrical conductivity measurements to derive major solute concentrations in karst systems
No full textHydrochemical data of karst springs provide valuable insights into the internal hydrodynamical functioning of karst systems and support model structure identification. However, the collection of high-frequency time series of major solute species is limited by analysis costs. In this study, we develop a method to retrieve the individual solute concentration time series and their uncertainty at high temporal resolution for karst springs by using continuous observations of electrical conductivity ((Figure presented.)) and low-frequency ionic measurements. Due to the large ion content and non-negligible concentrations of aqueous complexes in karst systems, the concentration of each solute species occurring as free ion and as part of aqueous complexes are computed separately. The concentration of species occurring as free ions are computed considering their contributions to the total (Figure presented.), whereas the concentration of the species as part of complexes are obtained from speciation calculations. The pivotal role of the complexation processes for the reconstruction of solute concentration time series starting from the (Figure presented.) signal is investigated in two karstic catchments with different geologies and temporal resolution of the available hydrochemical datasets, that is the Kerschbaum dolostone system in Austria and the Baget limestone system in France. The results show that complexation processes are significant and should be considered for the estimation of the total solute concentration in case of SO4, Ca, Mg and HCO3. The (Figure presented.) signal of a karst spring can be used to interpolate and quantify the dynamics of those solutes characterized by large contribution (approximately >6%) to the total (Figure presented.) and low relative variability, that is HCO3, Ca and Mg. Moreover, the presented method can be used to estimate concentrations of solutes when applied to karst systems with stationary and hydrogeochemical homogeneous contributing area. On the contrary, the method is affected by large uncertainty in case of dynamic systems characterized by varying contributions of water from different geological areas. This study aims to contribute to the problem of hydrogeochemical data availability and to support future works on karst systems conceptualization.Sanitary Engineerin
Characterizing and Modelling Fractures and Karst in Carbonate Units - The Porocarste Project
No full textWe investigated the Quaternary epigenic karst system in the Jandaíra Formation, a Turonian–Campanian carbonate platform in the Potiguar basin, northeastern Brazil. We concentrated our investigation in the vadose zone of the present-day karst, but also used borehole data. The leaching zones are preferentially concentrated along pre-solution openings composed of faults, joints, and bedding planes. These dissolved and enlarged faults and beddings form a system of caves and sinkholes, which must be included in the architecture of karst systems. This controlled-karst architecture presents a predictable geometry. This process occurs when the carbonate platform is exposed for a long period and can be thus affected by surface processes such as dissolution of erosion. The Quaternary epigenic karst features we describe may correlate with paleokarst systems in other carbonate platforms.Structural EngineeringCivil Engineering and Geoscience
Geomorphology and Hydrology of Karst Terrains
No full textKarst terrains - irregular limestone regions characterized by sinkholes, underground streams and caverns - have long been of interest because of the dramatic landscapes and the challenge of cave exploration. But the geomorphology and hydrology of karst drainage systems are now of interest to water supply specialists, urban planners, and environmental engineers. This graduate-level text discusses the chemistry of karst waters, the processes of sedimentary in-filling, the origins of caves, and the evolution of karst systems through geologic time. Since karst develops predominently by chemical processes, this text is written from the point of view of the chemistry of limestone solution. The approach is more quantitive and process-oriented than that of existing textbooks, and the author includes material on environmental problems in karst regions, including land use and land management, water supply, and pollution control
Polystichum tiankengicola (Dryopteridaceae), a New Species from a Karst Sinkhole from Guizhou, China
No full textA new pteridophyte species, Polystichum tiankengicola Li Bing Zhang, Q. Luo & P. S. Wang (Dryopteridaceae), is described and illustrated from a high-elevational karst sinkhole from Guizhou Province in China. Morphological evidence suggests that P. tiankengicola is a member of series Basigemmifera W. M. Chu & Z. R. He in section Micropolystichum Daigobo, based on the presence of bulbils on rachis and the small habit. Polystichum tiankengicola is unique in series Basigemmifera in having a bulbil at both the base and apex of the rachis. Morphologically, the new species is most similar to P. capillipes (Baker) Diels, also of series Basigemmifera, but beyond the distinctive number of bulbils on the rachis, P. tiankengicola has a truncate lamina apex and its perispores have an echinate sculpture with irregular ridges, in contrast to P. capillipes, which has only one bulbil at the base of the rachis, an acuminate lamina apex, and perispores that have a granular sculpture. Polystichum tiankengicola is found only from the highest elevational, karst sinkhole known in China (2530 m) and is considered to be Critically Endangered (CR), based on IUCN Red List criteria
Effects of reservoirs in karst areas on earthquakes
No full textJanuary 1980.Bibliography: page 44.The investigation leading to this paper on the effects of reservoirs in karst areas on earthquakes is the product of the bilateral U.S. - Yugoslavian research project on hydrology and water resources of karst regions. The research was mainly conducted in Yugoslavia, but also partially at Colorado State University
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Why Equality Matters
No full textKenneth L. Karst, a prolific author in the field of constitutional law, gave the fall quarter Sibley Law Lecture October 28.The UCLA law professor addressed the topic Why Equality Matters in his lecture, which was the 56th in the John A. Sibley Lecture Series.
A full summary of this event was published in the Advocate Magazine Volume 19, Issue 1, Spring 1983 on page 2: https://digitalcommons.law.uga.edu/advocate/vol19/iss1/1
Why Equality Matters
No full textKenneth L. Karst, a prolific author in the field of constitutional law, gave the fall quarter Sibley Law Lecture October 28.The UCLA law professor addressed the topic Why Equality Matters in his lecture, which was the 56th in the John A. Sibley Lecture Series.
A full summary of this event was published in the Advocate Magazine Volume 19, Issue 1, Spring 1983 on page 2: https://digitalcommons.law.uga.edu/advocate/vol19/iss1/1
Index to Cave Notes/Caves and Karst, June 1973
No full textContent: Indexes to Cave Notes/Caves and Karst -- Author and Title Index -- Subject Index -- Geographic Indexhttps://digitalcommons.usf.edu/caves_and_karst/1078/thumbnail.jp
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