نتایج جستجو برای: silicate rock
تعداد نتایج: 49032 فیلتر نتایج به سال:
Silicate glasses are ubiquitous on terrestrial planets wherever molten rock – generated by volcanism or impacts is quenched air water. Hence, they provided ready and abundant reactive solid surfaces for prebiotic chemistry the early Earth. Here, we show that glass composition determines basicity, which in turn modulates outcome of synthetic processes such as polymerization 3’,5’ cyclic guanosin...
Akermanite (Akg0) coexists with monticellite (Mo92) and wollastonite (Wo99) in an unusual calc-silicate xenolith in anorthosite at Cascade Slide in the Adirondack Mountains, New York. Experimental results bearing on the stability of akermanite have been evaluated through calculations based on thermochemical data and by chemical analysis of experimental products (Yoder 1975). A temperature of 75...
–Carbon bound in gibbsite, collected from a residual weathering profile developed on a Paleozoic granite in the Georgia Piedmont, was examined for its C content and found to be geologically young. The study site, located at the Panola Mountain Research Watershed, has developed a granite–saprolite–soil regolith in which C-gibbsite model ages deep within the profile (C-horizon) average about 8000...
The rate of K+ leaching from soil minerals such as K-feldspar is believed to be too slow to provide agronomic benefit. Currently, theories and methods available to interpret kinetics of mineral processes in soil fail to consider its microfluidic nature. In this study, we measure the leaching rate of K+ ions from a K-feldspar-bearing rock (syenite) in a microfluidic environment, and demonstrate ...
Conventional row crop agriculture for both food and fuel is a source of carbon dioxide (CO2) and nitrous oxide (N2O) to the atmosphere, and intensifying production on agricultural land increases the potential for soil C loss and soil acidification due to fertilizer use. Enhanced weathering (EW) in agricultural soils-applying crushed silicate rock as a soil amendment-is a method for combating gl...
The composition of the silicate portion of Martian regolith fines indicates derivation of the fines from mafic to ultramafic igneous rocks, probably rich in pyroxene. Rock types similar in chemical and mineralogical composition include terrestrial Archean basalts and certain achondrite meteorites. If these igneous rocks weathered nearly isochemically, the nontronitic clays proposed earlier as a...
Based on analysis of groundwater hydrochemical and isotopic indicators, this article aims to identify the groundwater flow systems in the Yangwu River alluvial fan, in the Xinzhou Basin, China. Groundwater delta(2)H and delta(18)O values indicate that the origin of groundwater is mainly from precipitation, with local evaporative influence. d-excess values lower than 10% in most groundwaters sug...
Apollo 14 regolith breccia 14076, long known to be uniquely endowed with high-alumina, silica-poor (HASP) material of evaporation-residue origin, has been found to contain a diverse suite of complementary condensates, dubbed GASP (gas-associated spheroidal precipitates). GASP occurs in two forms: as glassy or extremely fine grained quenched-melt spheroids, mostly less than 5 lm across; and as q...
In the west of Marand in Ghekhlar area, the Upper MiocenePleistocene volcanic rocks, including intermediate to acidic basic alkaline and lampr~phyric, are extensive exposed. Trachy-andesite rocks of this area contain carbonatite-silicate xenoliths, which according to mineralogical studies, are calcite - carbonatite type. The minerals of calcite, diopside, anorthite, phlogopite, amphibole, ...
Kandovan historical village is one of the most important attractive tourist sites on rocky architectures in East Azerbaijan province from the Skirts of Sahand Volcano NW of Iran. This village with unique landscape and rocky historical architecture is on the surfaces of a tuff layer. Nowadays, natural surface weathering of this architecture and intensity of decay phenomena in Kandovan village ro...
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