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The Global ETD Search service is a free service for researchers
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Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Showing 1 to 3 of 3 (0.048 seconds)Spelling suggestions: "subject:"drinkwater"" "subject:"deepwater""
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Examining the Spatial and Temporal Variations in CO<em>2</em> Partial Pressure in the Deep Vadose Zone Above Jinapsan Cave, GuamRegis, Jamar 21 March 2019 (has links)
Carbon dioxide is the primary driver of dissolution and precipitation reactions in epigene limestone caves. While much work has been conducted on CO2 dynamics involved in dissolution in the phreatic zone, less research has been conducted on vadose CO2 dynamics, especially in tropical caves developed in eogenetic limestones. In this study, we investigate spatial and temporal variation in pCO2 in the deep vadose zone of eogenetic limestone above Jinapsan Cave, located in northern Guam. Five years of carbonate chemistry data from three dripwater sites in Jinapsan Cave (Flatman, Station1, and Trinity) were used to model the theoretical pCO2 with which infiltrating waters had likely equilibrated along flow paths between the soil and the cave. Theoretical pCO2 essentially models the amount of CO2 that would need to be added to dripwaters that have degassed and become supersaturated with respect to calcite upon entering a lower CO2 cave void in order to return the water to equilibrium. Theoretical pCO2 values range from 10-2.8 to 10-1.8 atm among the three sites examined. These results were generally lower compared to similar studies in telogenetic and continental karst, which range from 10-3.7 to 10-0.96 atm. Theoretical pCO2 data from Jinapsan Cave have significant differences among the three drip sites, with the site closest to the entrance (Flatman) having the highest values and the farthest from the entrance (Trinity) having the lowest values; in addition, the values also have a great seasonal variability. Low theoretical pCO2 values in Jinapsan Cave’s dripwaters indicate that vadose zones in eogenetic limestone may be better ventilated, and hence have lower pCO2, than those in telogenetic limestone. The ventilation of the vadose zone is facilitated by high matrix porosity and permeability of eogenetic limestone and may be driven by barometric pressure changes or wind.
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Výzkum nenasycené zóny v severní části Moravského krasu / Study of vadose zone in northern part of Moravian KarstGregorová, Anita January 2012 (has links)
This study is focused on the flow through the uppermost part of the unsaturated zone in karstified areas. The information about distribution of transit times and chemical reactions taking place in the unsaturated zone is based on isotopic and chemical composition of cave dripwaters, precipitations and water caught by gravitation lysimeters. The water balance was calculated using measurements of intensity of dripwaters and amounts of water caught by lysimeters and rain gauges. The velocity of a hydraulic shockwave between monitored objects was also estimated according to the delay between significant precipitation event and dripwater intensity increase. The field study took place in the Němcova 1 cave in the northern part of Moravian Karst, near the village Suchdol. It was carried out during the hydrological year 2010/2011. The cave is about 13 m under the surface. The information about composition of overlaying rock above the cave was obtained using geoelectrical and electromagnetic measurements. Studied geological environment is built of 0.5 - 1.5 m of soil, 0.5 - 3.5 m of epikarst and a layer of massive limestone as thick as 10 m. About 70 to 90 % of dripwaters have residence time over 4 years. The distribution of transit time of younger water can be described using the exponencial model (well...
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Stable isotope investigations on speleothems from different cave systems in Germany. / Stabile Isotopen-Untersuchungen an Speläothemen aus verschiedenen Höhlensystemen in Deutschland.Nordhoff, Peter 13 June 2005 (has links)
No description available.
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