نتایج جستجو برای: pyroxene andesite
تعداد نتایج: 1838 فیلتر نتایج به سال:
The Razei region in the northwest of Ardabil is considered a part of West Alborz-Azerbaijan. Rocks in this area were created by Eocene volcanic activities. These rocks range from andesite to olivine basalt. The common texture of these rocks is Porphyritic with microlithic matrix. The phenocrysts of these rocks are often clinopyroxene, plagioclase, and olivine. The texture is made of microlithic...
The Kuh-e Mish plutonic complex (KPC) is located about 30 km south of Sabzevar. Based on tectonic division, it is part of Sabzevar zone. The Stratigraphic units of the area are conglomerate, tuff, and sandstone of the Paleogene, radiolarites, andesite and tuff unit of Upper Cretaceous. This collection consists of two plutonic rocks types. (1): The granitoid complex of northern Kuh-e Mish which ...
The Eocene-Oligocene Sarbisheh volcanic complex is a part of the Lut-Sistan Zone that outcrops in eastern Iran. In the east of this complex, three groups of volcanic rocks (i.e., andesite, dacite, and rhyolite) exist. Plagioclase as the main mineral of these rocks is found with varying micro-textures. Based on a changing trend in the concentration of anorthite, the developed micro-textures (coa...
In Zoolesk area, about 11km northeast of Sarbisheh city in South Khorasan Province, volcanic rocks including andesite, dacite and rhyolite have cropped out where andesitic lavas have the maximum distribution and have been studied in this research.The main textures of andesites are porphyry with microlitic-glassy groundmass, glomeroporphyry and vesicular. Minerals forming andesites include plagi...
سنگهای آتشفشانی با ترکیب تفریتی و فونوتفریتی با سن ائوسن بالایی در رشته کوه بزقوش، شمال غرب ایران گسترش قابل ملاحظهای دارند. این سنگهای آتشفشانی هم به صورت گدازههایی با حجم زیاد که عمدتاً در قسمت شمالی رشته کوه بزقوش قرار گرفتهاند و با یک روند شرقی-غربی بر روی آندزیتهای مگاپورفیری ائوسن میانی قرار گرفته اند، دیده میشوند و هم به صورت لنزهایی کوچک در بین سنگهای ولکانی کلاستیکی جای گرفتهان...
Introduction: Crystal size distribution (CSD) analysis is a useful technique for quantifying textural information and linking petrographic texture to original crystallization conditions [1]. In previous studies we have conducted CSD analyses of multiple thin sections of nakhlite meteorites [2], and several basaltic and mixed shergottites [3,4]. Based on results of these analyses, we derived cry...
The first observation of the vibrational spectrum of the synthetic pyroxene Li-kosmochlor (LiCrSi2O6) is reported herein. The Raman and visible spectra are reported as a function of pressure. Though the pyroxene retains its P21/c symmetry, changes in the Raman spectra are observed between 6.8 and 7.7 GPa, possibly due to the formation of an additional bond between Li and O3 or some other transi...
Introduction: The behavior of multivalent elements such as iron, chromium, vanadium, and euro-pium in magmatic systems reflects the f O2 of the environment. The oxidation state of these elements will influence the mineral assemblage, crystallization sequence , and element partitioning[1]. The effect of f O2 on the relative proportions of divalent and trivalent Eu has proven to be a useful tool ...
CM chondrites are aqueously altered rocks that contain ~9 wt.% H2O (indigenous water) [1] bound in phyllosilicates [2-4]; also present in the matrix are serpentinetochilinite intergrowths (PCP), pentlandite, and Ni-bearing pyrrhotite. The extent of alteration varies from meteorite to meteorite. Some CM chondrites contain well-delineated metallic-Fe-Ni-bearing, olivineand pyroxene-rich chondrule...
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