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291.
292.
The western Tianshan range is a major Cenozoic orogenic belt in central Asia exposing predominantly Paleozoic rocks including granite. Ongoing deformation is reflected by very rugged topography with peaks over 7000 m high. Active tectonic deformation is tied to an E–W trending fracture and fault system that sections the mountain chain into geologically diverse blocks that extend parallel to the orogen. In the Muzhaerte valley upwelling hot water follows such a fault system in the Muza granite. About 20 L min−1 Na–SO4–Cl water with a temperature of 55 °C having a total mineralization of about 1 g L−1 discharge from the hot spring. The water is used in a local spa that is frequented by the people of the upper Ili river area. Its waters are used for balneological purposes and the spa serves as a therapeutic institution. The major element composition of the hot water is dominated by Na and by SO4 and Cl, Ca is a minor component. Dissolved silica (1.04 mmol L−1) corresponds to a quartz-saturation temperature of 116 °C and a corresponding depth of the source of the water of about 4600 m. This temperature is consistent with Na/K and Na/Li geothermometry. The water is saturated with respect to fluorite and contains 7.5 mg L−1 F− as a consequence of the low Ca-concentration. The water is undersaturated with respect to the primary minerals of the reservoir granite at reservoir temperature causing continued irreversible dissolution of granite. The waters are oversaturated with respect to Ca–zeolite minerals (such as stilbite and mesolite), and it is expected that zeolites precipitate in the fracture pore space and in alteration zones replacing primary granite. 相似文献
293.
Lukas Plan Kurt Decker Robert Faber Michael Wagreich Bernhard Grasemann 《Environmental Geology》2009,58(2):285-297
High alpine karst plateaus are recharge areas for major drinking water resources in the Alps and many other regions. Well-established
methods for the vulnerability mapping of groundwater to contamination have not been applied to such areas yet. The paper characterises
this karst type and shows that two common vulnerability assessment methods (COP and PI) classify most of the areas with high
vulnerability classes. In the test site on the Hochschwab plateau (Northern Calcareous Alps, Austria), overlying layers are
mostly absent, not protective or even enhance point recharge, where they have aquiclude character. The COP method classifies
82% of the area as highly or extremely vulnerable. The resulting maps are reasonable, but do not differentiate vulnerabilities
to the extent that the results can be used for protective measures. An extension for the upper end of the vulnerability scale
is presented that allows identifying ultra vulnerable areas. The proposed enhancement of the conventional approach points out that infiltration conditions are of key importance
for vulnerability. The method accounts for karst genetical and hydrologic processes using qualitative and quantitative properties
of karst depressions and sinking streams including parameters calculated from digital elevations models. The method is tested
on the Hochschwab plateau where 1.7% of the area is delineated as ultra vulnerable. This differentiation could not be reached
by the COP and PI methods. The resulting vulnerability map highlights spots of maximum vulnerability and the combination with
a hazard map enables protective measures for a manageable area and number of sites. 相似文献
294.
Kurt von Storch 《Environmental Earth Sciences》2009,59(1):21-24
The BOCIM method (bottleneck-focused continuous improvement) has been designed to support the optimum adaptation of a local
water resources management depending on regional conditions to ensure a sustainable supply of water. Being an interdisciplinary
approach, the BOCIM method tries to take into account all the factors affecting the water supply. Geared to solving water
problems, it is used to: identify and solve whatever the core problem happens to be in a regional water system by applying
the bottleneck-concentrated strategy (Mewes in Orell Füssli Management, 112 p, 2000); replace the fragmented project-based approach with continuous improvement; run a management system-orientated quality management
standard (e.g. ISO 9001). 相似文献
295.
The study presents composition data of 87 surface water samples from high alpine catchments of the Zermatt area (Swiss Alps). The investigated area covers 170 km2. It was found that the surface runoff acquires the dissolved solids mostly by reaction of precipitation water with the minerals of the bedrock. Total dissolved solids (TDS) vary from 6 to 268 mg L?1. All collected water shows a clear chemical signature of the bedrock mineralogy. The contribution of atmospheric input is restricted to small amounts of ammonium nitrate and sodium chloride. NH4 is a transient component and has not been detected in the runoff. Evaporation is not a significant mechanism for TDS increase in the Zermatt area. The chemical composition of the three main types of water can be related to the mineralogy of the dominant bedrock in the catchments. Specifically, Ca-HCO3 (CC) waters develop from metamorphic mafic rocks and from carbonate-bearing schists. Mg-HCO3 water originates from serpentinites and peridotites. Ca-SO4 (CS) waters derive from continental basement rocks such as pyrite-rich granite and gneiss containing oligoclase or andesine. The collected data suggest that, together with reaction time, modal sulfide primarily controls and limits TDS of the waters by providing sulfuric acid for calcite (CC waters) and silicate (CS waters) dissolution. If calcite is present in the bedrock, its dissolution neutralizes the acid produced by sulphide weathering and buffers pH to near neutral to weakly alkaline conditions. If calcite is absent, the process produces low-pH waters in gneiss and granite catchments. The type of bedrock and its mineral assemblage can be recognized in water leaving very small catchments of some km2 area. The large variety of water with a characteristic chemical signature is an impressive consequence of the richly diverse geology and the different rock inventory of the local catchments in the Zermatt area. 相似文献
296.
297.
Summary. The viscoelastic response of the Earth to the mass displacements caused by late Pleistocene deglaciation and concomitant sea level changes is shown to be capable of producing the secular motion of the Earth's rotation pole as deduced from astronomical observations. The calculations for a viscoelastic Earth yield a secular motion in the direction of 72° W meridian which is in excellent agreement with observed values. The average Newtonian viscosity and the relaxation time obtained from polar motion data are about (1.1 ± 0.6)1023 poise (P) and 104 (1 ± 0.5) yr. The non-tidal secular acceleration of the Earth can also be attributed to the viscoelastic response to deglaciation and results in an independent viscosity estimate of 1.6 × 1023 P with upper and lower limits of 1.1 × 1023 and 2.8 × 1023 P. These values are in agreement with those based on the polar drift analysis and indicate an average mantle viscosity of 1–2 × 1023 P. 相似文献
298.
299.
300.