Geological, environment

Site characterization studies include a surface-based testing program, potential environmental impact, and societal aspects of the repository. Performance assessment considers both the engineered barriers and the geologic environment. Among features being studied are the normal water flow, some release of carbon-14, and abnormal events such as volcanic activity and human intmsion. The expected date for operation of the repository is 2013. 

Barite [13462-86-7], natural barium sulfate, BaSO, commonly known as barytes, and sometimes as heavy spar, tiU, or cawk, occurs in many geological environments in sedimentary, igneous, and metamorphic rocks. Commercial deposits are of three types vein and cavity filling deposits residual deposits and bedded deposits. Most commercial sources are replacement deposits in limestone, dolomitic sandstone, and shales, or residual deposits caused by differential weathering that result in lumps of barite enclosed in clay. Barite is widely distributed and has minable deposits in many countries. 

Several of these mechanisms can be ruled out based on the geologic environment of the Hokuroku district, because the geologic environment of the Hokuroku area during the Miocene was quite different from that of areas of evaporite formation. 

In Fig. 1.85 iron contents of epidote from two different geologic environments, island arc and oceanic ridge or ophiolite, are summarized. It can be seen in Fig. 1.85 that the iron content of epidote from ridge basalt and ophiolite is generally lower than... 

During Miocene age most of this province was in a submarine environment. Violent submarine volcanism (bimodal and basic type) took place at Miocene age in this province. This geologic environment may be related to an extensional stress regime (Uyeda and Kanamori, 1979). The Kuroko deposits have been formed related to this tectonic situation. 

The deposits have been formed under the subaerial environment. No contribution of seawater and low /s2 and /02 conditions are consistent with the geologic environment. 

The sulfur isotopic data are consistent with geologic environments of Hg and Sb deposits Sedimentary rocks are dominant and marine rocks are not present in Sb-Hg mineralization districts. However, a few samples of stibnite and cinnabar from the deposits in Green tuff region display high S S values. In contrast of this interpretation on the origin of sulfur, Ishihara and Sasaki (1994) thought that sulfur came from ilmenite-series granific rocks. However, these rocks are not found in the north Hokkaido. 

Tatsumi, T. and Watanabe, T. (1971) Geological environment of formation of the Kuroko-type deposits. Mining Geology Special Issue, 3, 216-220. 

Kawahata and Shikazono (1988) summarized S S of sulfides from midoceanic ridge deposits and hydrothermally altered rocks (Fig. 2.42). They calculated the variations in 5 " S of H2S and sulfur content of hydrothermally altered basalt as a function of water/rock ratio (in wt. ratio) due to seawater-basalt interaction at hydrothermal condition (Fig. 2.43) and showed that these variations can be explained by water/rock ratio. The geologic environments such as country and host rocks may affect S S variation of sulfides. For example, it is cited that a significant component of the sulfide sulfur could... 

The uranium and thorium decay-series contain radioactive isotopes of many elements (in particular, U, Th, Pa, Ra and Rn). The varied geochemical properties of these elements cause nuclides within the chain to be fractionated in different geological environments, while the varied half-lives of the nuclides allows investigation of processes occurring on time scales from days to 10 years. U-series measurements have therefore revolutionized the Earth Sciences by offering some of the only quantitative constraints on time scales applicable to the physical processes that take place on the Earth. 

Aqueous waste solutions should be disposed of properly, and in particular solutions carrying heavy metals need to be treated. Untreated solutions, if released, can contaminate the geological environment. 

There are a number of deposits of this type with different origins. The geological environments are well described in the literature [8,10]. Most economical PGM chromite deposits... 

Trace elements are useful tracers of geochemical processes mostly because they are dilute their behavior depends primarily on the trace element-matrix interaction (e.g., Rb-host feldspar, Sr-calcite) and very little on the trace-trace interaction (e.g., Rb-Rb, Sr-Sr). Consequently, the distribution of trace elements among natural phases largely obeys the linear Henry s law. The modeling of trace elements in various geological environments (magmas, hydrothermal fluids, seawater,...) relies on three different aspects... 

Trial and error is often the typical procedure that is used to implement enhanced biorestoration. In simple cases of gasoline cleanups, these may be appropriate however, when the chemicals involved are recalcitrant (difficult to degrade), toxic, or present in a complex geologic environment (i.e., low-permeability soil, lateral or vertical heterogeneities, etc.), enhanced biorestoration can be difficult, and risk assessment-type analyses may be more suited for a particular site. 

The papers on the "Degradation of Lignin in Geological Environments a ppeared in a special issue of Geochimica et Cosmochimica Acta. 

Stevenson F. J. (1983). Trace metal-organic matter interaction in geologic environment. In The Significance of Trace Elements in Solving Petrogenetic Problems and Controversies, S. Au-gustitis, ed. Theophrastus Publications, Athens. 

Lydon, J.W., Paakki, J.J., Anderson, H.E., Reardon, N.C. 2000. An overview of the geology and geochemistry of the Sullivan deposit. In Lydon, J.W., Hoy, T., Slack, J.F. Knapp, K. (eds.), The Geological Environment of the Sullivan Deposit, British Columbia, Geological Association of Canada, Mineral Deposits Divison, Special... 

Table 1. Cathodoluminescence colors of quartz (and inferred geologic environment) from the Elmtree Deposit (ED) and Guitard...

Few mineral groups contain as many species, or occur over as wide a range of geological environments, as the amphibole group. The forms and habits... 

As must be obvious, we have only touched on the natural occurrences of crystalline fibrous Si02- For example, Si02, usually quartz, often replaces fibrous minerals of another composition as rock masses are altered. Si02 also occurs in fibrous form within some plants (phytoliths) and in the soil. To summarize, in addition to the usual and common occurrences of the mineral quartz and its varieties, several silica polymorphs occur as fibers in a variety of biologic and geologic environments. 

As used here, the term biosphere includes the total sum of living matter - plants, animals, and microbial biomass and the residnes of the living matter in the geological environment snch as coal and petrolenm. A fairly close balance exists between photosynthesis and respiration, although over the whole of geological time respiration has been exceeded by photosynthesis, and the energy derived from this is stored mostly in disseminated organic matter, and, of course, in coal and petroleum. 

Genetic type Fe source Texture Main minerals Geological environment Type name... 

The natural fluor-apatites in our study consisted of 75 samples from a variety of geologic environments. Concentrations of potential luminescence impurities in several samples are presented in Table 4.4. 

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