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A total of 268 thermal spring samples were analyzed for total soluble As using reduced molybdenum-blue; 27 of these samples were also analyzed for total Sb using flame atomic absorption spectrometry. At Yellowstone the atomic ratio is nearly constant among neutral-alkaline springs with Cl > 100 mg L?1, and within restricted geographic areas, indicating no differential effects of adiabatic vs. conductive cooling on arsenic. The ratio increases with silica and decreases with decreasing ; the latter relationship is best exemplified for springs along the extensively sampled SE-NW trend within the Lone Star-Upper-Midway Basin region. The relationship between and at Yellowstone suggests a possible rock leaching rather than magmatic origin for much of the Park's total As flux. Condensed vapor springs are low in both As and Cl. Very high ratios ( > 1000) are associated exclusively with highly diluted (Cl < 100 mg L?1) mixed springs in the Norris and Shoshone Basins and in the Upper White Creek and Firehole Lake areas of Lower Basin. The high ratios are associated with acidity and/or oxygen and iron; they indicate precipitation of As following massive dilution of the Asbearing high-Cl parent water.Yellowstone Sb ranged from 0.009 at Mammoth to 0.166 mg L?1 at Joseph's Coat Spring. Within basins, the ratio increases as the ratio decreases, in marked contrast to As. Mixed springs also have elevated ratios. White (1967) and Weissberg (1969) previously reported stibnite (Sb2S3), but not orpiment (As2S3), precipitating in the near surface zone of alkaline geothermal systems. 相似文献
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Robert Elihu Stauffer 《Geochimica et cosmochimica acta》1982,46(3):465-474
Potential solubility controls on phosphorus in Yellowstone National Park geothermal waters were investigated using the analytical phosphate estimates of Stauffer and Thompson (1978), the computer program, WATEQF, and adopting the equilibrium constant: for fluorapatite (FAP = Ca5(PO4)3F) dissolution. The near-boiling high-Cl geyser and spring effluents are at or near saturation with respect to (with) FAP. The sixteen representative springs in this category had FAP saturation indices () ranging from ? 3.2 to +4.9 and averaging +0.9. The strongly positive indices were all associated with the highly alkaline conditions resulting from adiabatic cooling in the near surface environment. Hot spring waters indicating extensive dilution (reduced Cl) by meteoric water have lower pH's, and despite PO4 and Ca concentrations an order of magnitude higher than the geysers, are still frequently undersaturated with FAP. The travertine-depositing “Mixed-water” springs are invariably supersaturated with FAP at ground surface and at or near saturation with hydroxylapatite. Supersaturation may result from kinetic inhibition of apatite crystallization by the elevated Mg2+, HCO3?, and lower temperatures in these springs. The phosphates may be residuals of the meteoric dilution water.Separately, if Strübel's temperature-dependent estimates of fluorite (CaF2) solubility are adopted, the high-Cl geysers and springs on “Geyser Hill” and at Norris are consistently undersaturated with CaF2 at the 90–100° orifice temperatures. The apparent disequilibrium may reflect fluorite equilibration at the much higher temperatures (> 200°C) in the deeper enthalpy reservoirs. 相似文献
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A reprocessing program to enhance the correlation between the surface geology and the seismic data has been completed for seismic line 9 (eastern 100 km) and line 10 in the central region of the Trans-Hudson Orogen of Saskatchewan, Canada. The new seismic images through lateral continuity of reflectivity provide sufficient detail to resolve the discrepancy between the low-dipping, layer-parallel and dextral-reverse nature of the Sturgeon-Weir shear zone (line 9) observed in the field and its steeply dipping (apparent) normal displacement character interpreted on the basis of the initial processing. Furthermore, the new interpretation provides a strong confirmation of the role of Pelican Thrust as a major detachment zone — the main `sole thrust' — along which juvenile allochthons have been carried across the Archaean microcontinental block. The images are also refined enough to suggest: (a) a boundary within the Pelican Thrust between its internal and external suites; (b) a possible boundary separating a lower (older?) Archaean basement from its upper (younger?) counterpart; and (c) sub-Moho events (M2) which reveal possible involvement of the upper mantle in the collisional tectonic process in addition to the well defined Moho (M1) which probably represents the youngest of the post-collisional detachments. 相似文献
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A brilliant smoking meteor appeared in a clear sky in bright sunlight at 11 a.m., July 24, 1922 near Wynyard, Saskatchewan, Canada. The sight and thunderous sounds were witnessed by many hundreds of people in the rural district but no craters or meteorites were found at that time. Investigation and interviews with surviving witnesses in 1981 indicated a defined area near Big Quill Lake in which a meteorite may have fallen. Field investigation led to the Wynyard meteorite which had been found by a farmer sometime in the late 1960's at 104° 11'W 51°33'N. The Wynyard meteorite is a chondrite weighing 3.5 kg. It is moderately weathered and it may or may not have been part of the 1922 fall. 相似文献
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Brian P. Reen David R. Stauffer Kenneth J. Davis Ankur R. Desai 《Boundary-Layer Meteorology》2006,120(2):275-314
The importance of soil moisture inputs and improved model physics in the prediction of the daytime boundary-layer structure during the Southern Great Plains Hydrology Experiment 1997 (SGP97) is investigated using the non-hydrostatic fifth-generation Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR) Mesoscale Model MM5. This is Part II of a two-part study examining the relationship of surface heterogeneity to observed boundary-layer structure. Part I focuses on observations and utilizes a simple model while Part II uses observations and MM5 modelling. Soil moisture inputs tested include a lookup table based on soil type and season, output from an offline land-surface model (LSM) forced by atmospheric observations, and high-resolution ( 800 m) airborne microwave remotely sensed data. Model physics improvements are investigated by comparing an LSM directly coupled with the MM5 to a simpler force-restore method at the surface. The scale of land surface heterogeneities is compared to the scale of their effects on boundary-layer structure.The use of more detailed soil moisture fields allowed the MM5 to better represent the large-scale (hundreds of km) and small-scale (tens of km) horizontal gradients in surface-layer weather and, to a lesser degree, the atmospheric boundary-layer (ABL) height, which was evaluated against observations measured by differential absorption lidar (DIAL). The benefits of coupling an LSM to the MM5 were not readily evident in this summertime case, with the model having particular difficulty simulating the timing of maximum surface fluxes while underestimating the depth of the mixed layer. 相似文献
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H.F. Malenda N.A. Sutfin G. Guryan S. Stauffer J.C. Rowland K.H. Williams K. Singha 《地球表面变化过程与地形》2019,44(9):1799-1815
Stratigraphy is a fundamental component of floodplain heterogeneity and hydraulic conductivity and connectivity of alluvial aquifers, which affect hydrologic processes such as groundwater flow and hyporheic exchange. Watershed-scale hydrological models commonly simplify the sedimentology and stratigraphy of floodplains, neglecting natural floodplain heterogeneity and anisotropy. This study, conducted in the upper reach of the East River in the East River Basin, Colorado, USA, combines point-, meander-, and floodplain-scale data to determine key features of alluvial aquifers important for estimating hydrologic processes. We compare stratigraphy of two meanders with disparate geometries to explore floodplain heterogeneity and connectivity controls on flow and transport. Meander shape, orientation, and internal stratigraphy affected residence time estimates of laterally exchanged hyporheic water. Although the two meanders share a sediment source, vegetation, and climate, their divergent river migration histories resulted in contrasting meander hydrofacies. In turn, the extent and orientation of these elements controlled the effective hydraulic conductivity and, ultimately, estimates of groundwater transport and hyporheic residence times. Additionally, the meanders’ orientation relative to the valley gradient impacted the hydraulic gradient across the meanders—a key control of groundwater velocity. Lastly, we combine our field data with remotely sensed data and introduce a potential approach to estimate key hydrostratigraphic packages across floodplains. Prospective applications include contaminant transport studies, hyporheic models, and watershed models. © 2019 John Wiley & Sons, Ltd. 相似文献