The results of the research on water mineralization, mineral composition, ash content, and organic matter content bottom sediments stagnant saline lakes in Southeastern Transbaikalia are presented. It has been established that various ratios feldspar, quartz, hydroxyl compounds, carbonate minerals universally found sediments. Sediments contain a small amount matter, which classifies them as hig...

lag is a general term applied to coarse grained (> 2 mm), hard, but partially weathered rockfragments, which are concentrated at the surface through attrition of finer materials. based on morphology,mineralogy and the origin of lag from the cobar region of australia, lag may be conveniently grouped intothree broad morpho-mineralogical categories; (a) those with a rough, blocky, lithic morpholog...

the area is located 20 km northwest of kashmar and about 4 km of kalateh taimour in khorasan razavi province. the study area is part of tertiary volcanic-plutonic belt north of daruneh fault and its situation in tectonic inliers between two important active faults, doruneh and taknar. volcanic rocks are mainly intermediate to acid pyroclastic type. they formed during early tertiary. the volcani...

salafchegan-khorhe volcanic rocks are exposed within urumieh-dokhtar magmatic belt. different kinds of volcanic and subvolcanic rocks of calc-alkaline to alkaline character have been reported throughout this magmatic belt. since, isotopic investigations are very useful for detection of magma petrogenesis and because no isotopic studies have been done in this area, so a geochemical and isotopic ...

The Mg/Ca ratios of biogenic calcite is commonly seen as a valuable palaeo-proxy for reconstructing past ocean temperatures. The temperature dependence of Mg/Ca ratios in bivalve calcite has been the subject of contradictory observations. The palaeoceanographic use of a geochemical proxy is dependent on initial, rigorous calibration and validation of relationships between the proxy and the ambi...

It is very important to investigate antimony geochemical behavior in order to identify its source, or reveal contamination processes, since antimony and its compounds are considered to be pollutants of high priority by the Environmental Protection Agency of the United States (USEPA). However, the concentration of antimony in most geological samples is very low, and its stable isotope mass diffe...

The Great Oxidation Event signals the first large-scale oxygenation of the atmosphere roughly 2.4 Gyr ago. Geochemical signals diagnostic of oxidative weathering, however, extend as far back as 3.3-2.9 Gyr ago. 3.8-3.7 Gyr old rocks from Isua, Greenland stand as a deep time outpost, recording information on Earth's earliest surface chemistry and the low oxygen primordial biosphere. Here we find...

The geochemical composition of sediment pore water was investigated in comparison with the composition of sediment particles and surface water in an estuary within one of the most industrialized areas in Latin America (Santos-Cubatão estuarine system, SE Brazil). Pore and surface waters presented anomalously high levels of F(-), NH4(+), Fe, Mn and P due to two industrial point sources. In the s...

We combine path-integral Monte Carlo methods with high-quality potential energy surfaces to compute equilibrium isotope effects in a variety of systems relevant to 'clumped' isotope analysis and isotope geochemistry, including CO2, N2O, methane, and propane. Through a systematic study of heavy-atom isotope-exchange reactions, we quantify and analyze errors that arise in the widely used Urey mod...