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Soil, mine tailing, and waste dump profiles above three mesothermal gold deposits in the Bohemian Massif with different anthropogenic histories have been studied. Their mineralogical, major element, and arsenic (As) contents and the contents of secondary arsenic minerals were analyzed. The As-bearing minerals were concentrated and determined using X-ray diffraction (XRD) analysis, the Debye-Scherrer powder method, scanning electron microscopy (SEM), and energy-dispersive microanalysis (EDAX). The amorphous hydrous ferric oxides (HFO), As-bearing goethite, K-Ba- or Ca-Fe- and Fe- arsenates pharmacosiderite, arseniosiderite, and scorodite, and sulfate-arsenate pitticite were determined as products of arsenopyrite or arsenian pyrite oxidation. The As behaviour in the profiles studied differs in dependence on the surface morphology, chemical and mineralogical composition of the soil, mine wastes or tailings, oxidation conditions, pH, presence of (or distance from) primary As mineralization in the bedrock, and duration of the weathering effect. Although the primary As mineralization and the bedrock chemical composition are roughly similar, there are distinct differences in the As behaviour amongst the Mokrsko, Roudný and Kaperské Hory deposits. 相似文献
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Geotectonics - The combination of geochemical analyses and geochronological data of Eocene volcanic rocks reveals a gradual shift in the dominant magmatic series from calc-alkaline to high-K... 相似文献
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The numerical results of downward continuation (DWC) of point and mean gravity anomalies by the Poisson integral using point,
single mean, and doubly averaged kernel are examined. Correct evaluation of the integral in its innermost zone is a challenging
task. To avoid instabilities, an analytical planar approximation is used in the innermost integration zone. In addition it
is shown that the single mean mode has the minimum discretization error. Downward continuation of point and mean anomalies
by singly and doubly averaged kernel are the same mean anomalies on the geoid. 相似文献
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H. R. Pourghasemi H. R. Moradi S. M. Fatemi Aghda E. A. Sezer A. Goli Jirandeh B. Pradhan 《Environmental Earth Sciences》2014,71(8):3617-3626
The aim of the presented study is to assess the fractal dimension (D) and the geometrical characteristics (length and width) of the landslides identified in North of Tehran, Iran. At first, the landslide locations (528 landslides) were identified by interpretation of aerial photographs, satellite images and field surveys, and then to calculate the fractal dimension (D), we used the computer programming named as FRACEK. In the next step, geometrical characteristics of each landslide such as length (L) and width (W) were calculated by ArcGIS software. The landslide polygons were digitized from the mentioned landslide inventory map and rotated based on movement direction. The fractal dimension for all landslides varied between 1.665 and 1.968. Subsequently, the relationship between the length/width ratios and theirs fractal D values for 528 landslides was calculated. The results showed that correlation coefficients (R), which are different regression models such as exponential, linear, logarithmic, polynomial, and power, between D and L/W ratio are relatively high, respectively (0.75, 0.75, 0.76, 0.78, and 0.75). It can be concluded that the fractal dimension values and geometry characteristics of landslides would be useful indices for the management of hazardous areas, susceptible slopes, land use planning, and landslide hazard mitigation. 相似文献
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