hydrothermal alteration processes are extensively took place on volcanic and pyroclstics of takestan area. existence of abundant, deep fracturing and subvolcanic intrusions are enhanced extend hydrothermal alteration zones. the following alteration zones are determined: propylitic, argillic, advanced argillic and sillicic. there are outcropped and widespread in different size and limit. formati...

Up to 0.4 mM 1,3-dimethylbenzene (m-xylene) was rapidly mineralized in a laboratory aquifer column operated in the absence of molecular oxygen with nitrate as an electron acceptor. Under continuous flow conditions, the degradation rate constant (pseudo-first order) was >0.45 h. Based on a carbon mass balance with [ring-C]m-xylene and a calculation of the electron balance, m-xylene was shown to ...

This study was part of the International Tundra Experiment (ITEX) and examined the effects of increased winter snow depth and decreased growing season length on the phenology of four arctic plant species (Betula nana, Salix pulchra, Eriophorum vaginatum, and Vaccinium vitis-idaea) and seasonal nitrogen availability in arctic snowbed communities. Increased snow depth had a large effect on the te...

The classification of mineralized areas into different groups based on mineral grade and prospectivity is a practical problem in the area of optimal risk, time, and cost management of exploration projects. The purpose of this paper was to present a new approach for optimizing the grade classification model of an orebody. That is to say, through hybridizing machine learning with a metaheuristic ...

The Great Basin of the Western United States has thin continental crust and geologic structures that have controlled the emplacement of significant precious and base metal mineralization. Many of the mineral deposits in the Great Basin were emplaced by hydrothermal processes that altered the mineralogy of their host rock assemblages and facilitated concentration of metals. In the 1960’s and 197...

different types of iron oxides deposits have been identified along the khaf – dorouneh volcanic and plutonic belt in north east of iran. kuh-e-zar is one of these ore deposits known as fe- oxide gold deposit. the main purpose of this paper is to detect and discriminate the iron oxide minerals in this area based on the etm+ data. data processing has been done by envi (environment for visualizing...