نتایج جستجو برای: pyroxene group
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Introduction: The oxidation state of Fe in Martian meteorites is a parameter of great interest and the ability to determine this value in micrometer scale samples is important [1]. Intense, tunable x-ray sources at large synchrotron storage rings are being exploited to examine the Fe K-absorption edge with energy resolution of ~1-1.5eV in spots of 10x15 μm on thin sections of a wide variety of ...
Dunites in ophiolites form by pyroxene dissolution and olivine precipitation during melt-peridotite interaction. We present structural geochemical data on peridotites from the Batin region (Wadi Tayin massif) of Oman ophiolite, where an exceptionally large (∼9.5 km long) dunite body was sampled ICDP Drilling Project (BA4A borehole). 900–1,200 m beneath petrological Moho, this is overlain harzbu...
this study investigated the effect of prior knowledge on the listening comprehension performance of fl learners. twenty students, male and female, drawn from the two intact groups of the senior and junior english language and literature majors were chosen as the participants of this study . the two groups were then randomly assigned into the experimental and control group. the experimental gr...
Minerals isostructural with sapphirine-1A, sapphirine-2M, and surinamite are closely related chain silicates that pose nomenclature problems because of the large number of sites and potential constituents, including several (Be, B, As, Sb) that are rare or absent in other chain silicates. Our recommended nomenclature for the sapphirine group (formerly aenigmatite group) makes extensive use of p...
[1] The !5 km of traverses and observations completed by the Opportunity rover from Endurance crater to the Fruitbasket outcrop show that the Meridiani plains consist of sulfate-rich sedimentary rocks that are largely covered by poorly-sorted basaltic aeolian sands and a lag of granule-sized hematitic concretions. Orbital reflectance spectra obtained by Mars Express OMEGA over this region are d...
[1] The Mössbauer spectrometer on Spirit measured the oxidation state of Fe, identified Fe-bearing phases, and measured relative abundances of Fe among those phases for surface materials on the plains and in the Columbia Hills of Gusev crater. Eight Fe-bearing phases were identified: olivine, pyroxene, ilmenite, magnetite, nanophase ferric oxide (npOx), hematite, goethite, and a Fe-sulfate. Adi...
[1] Using the Moon Mineralogy Mapper(M), we examine the Marius Hills volcanic complex for the first time from 0.46 to 2.97 mm. The integrated band depth at 1 mm separates the mare basalts on the plateau in two units: (1) a strong 1 mm band unit of localized lava flows within the plateau that has similar olivine‐rich signatures to those of the nearby Oceanus Procellarum and (2) a weaker 1 mm ban...
Extrusive igneous rocks are formed the main part of geological units in northeast region of Birjand. Investigation shows that these igneous rocks can be divided into rhyolitic, dacitic, andesitic and an especial group including basaltic andesite and basalts. In Later group that differ from the others according to geochemical and mineralogical characteristics, there are limited outcrops of high ...
Geochemical, isotopic and age constraints support a comagmatic origin for Ghuweir Mafics and the Feinan A-type granites. The two rocks types, named collectively in this paper as the Feinan Ghuweir Magmatic Suite (FGMS), formed between 556 and 572Ma ago according to Rb–Sr whole-rock dating. FGMS has low Sr initial ratios, which preclude a significant contribution of much older crust in the magma...
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