نتایج جستجو برای: chromite
تعداد نتایج: 697 فیلتر نتایج به سال:
By examining the minor and trace element contents of chromites from three intrusions—the Bushveld Complex (South Africa), Stillwater (USA), Great Dyke (Zimbabwe)—and comparing these chromite compositions with those magmas which they could have formed (komatiites picrites) we conclude that ( i) variations in Ti, V, Sc, Ga across stratigraphy individual layers do not support model magma mixing le...
No genetic link between the two main types of chromitite, stratiform and podiform chromitites, has ever been discussed. These chromitite have very different geological contexts; one is a member layered intrusions, representing fossil magma chambers, in crust, forms pod-like bodies, conduits, upper mantle. Chromite grains contain peculiar polymineralic inclusions derived from Na-bearing hydrous ...
Abstract Drilling related to development of the platinum-group element deposit J-M Reef Stillwater Complex returned samples a rare chromitite seam between anorthosite and norite in discordant anorthositic body. Plagioclase core An concentrations are marginally higher modestly reversely zoned on side (average Ancore = 83·8; average – Anrim –1·1) as compared with 82·5; +1·0). The anorthosites als...
cobalt chromite (cocr2o4) with normal spinel structure, shows catalytic activity for oxidation of unburned methane in the natural gas vehilcles (ngv). in this study, cocr2o4 nanoparticles were synthesized through a conventional co-precipitation technique and investigated for the catalytic combustion of methane. cobalt nitrate hexahydrate, chromium nitrate nonahydrate and ammonia solution (25%) ...
We examined oxygen three-isotope ratios of 48 extraterrestrial chromite (EC) grains extracted from mid-Ordovician sediments from two different locations in Sweden, and one location in south-central China. The ages of the sediments ( 470 Ma) coincide with the breakup event of the L chondrite parent asteroid. Elemental compositions of the chromite grains are generally consistent with their origin...
heavy metal concentration in the soils and sediments has increased worldwide during the last century due to the mining, smelting, and industrial activities. the forumad chromite deposit is located in the sabzevar ophiolitic complex (soc), with a long history of mining activities, yet very little is known about the heavy metal contamination in its surrounding environment. in this research work, ...
electron-probe microanalyses and scanning electron microscopy of chrornitites from some ultramafic members of neyriz ophiolite indicate that sulifides of platinum- group minerals (pgms) occur as solid inclusions in chromite grains. laurite with the general formula of (ru ,os ,lr ) s , and erlichmanite are the main identified sulfide phases. the pgms occur as 4 to 20 microns euhedral to rectangu...
the study area is located in the south of kerman province and in the esphandoghe- dolatabad zone. numerous chromite ores were found in the area that has been explored by surface outcrops. with respect to the previous exploration- exploitation works and the absence of the pilot layer, the best option was the boreholes’ drilling was the best choice in order to complete the detailed information. f...
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