نتایج جستجو برای: felsic composition
تعداد نتایج: 260277 فیلتر نتایج به سال:
Mineral chemistry of micas from the subduction-related mafic and felsic alkaline rocks of the Kaleybar alkali-gabbro and the Bozqush nepheline syenite was determined. The micas generally occur as large poikilitic grains with Fe-Ti oxides and mafic minerals and give the rocks a spotted texture. Micas in the alkali-gabbro sometimes display a distinct lamination. Based on the International Mineral...
available online at http://meteoritics.org Evidence for K-rich terranes on Vesta from impact spherules J. A. BARRAT1, 2*, M. BOHN1, 2, PH. GILLET3, and A. YAMAGUCHI4 1Université Européenne de Bretagne, France 2CNRS UMR 6538 (Domaines Océaniques), U.B.O.-I.U.E.M., Place Nicolas Copernic, 29280 Plouzané Cedex, France 3Laboratoire des Sciences de la Terre, CNRS UMR 5570, Université de Lyon, Ecole ...
the bundelkhand-aravalli craton is the most important lithotectonic unit in the central and western india where paleoproterozoic aravalli supracrustal sequence has been deposited over an archaean basement, the latter also known as the banded gneiss complex (bgc). a ne-trending linear metasedimentary sequence, designated as the jahazpur belt occurs along the eastern fringe of the aravalli superg...
Marie and intermediate granulite xenoliths, collected from Cenozoic alkali basalts, provide samples of the lower crust in western Saudi Arabia. The xenoliths are metaigneous two-pyroxene and garnet granulites. Mineral and whole rock compositions are inconsistent with origin from Red Sea rift-reIated basalts, and are compatible with origin from island arc calc-alkatine and low-potassium tholeiit...
The Qalaylan pluton of Late Jurassic age is composed of intermediate and felsic rocks that crop out in the northern Sanandaj-Sirjan Zone. A body is comprising alkaline, high K, Ferroan A1-type rocks with contrasting aspects; whiles, Nd-Sr primitive isotopic composition consistent with a mantle source. On the other hand, inherited zircon cores (with a range of 230 – 2700 Ma) and elevated Nd mode...
Gabbroic pluton of Bagham is located in southeastern Ardestan and has intruded into Eocene volacanic rocks. The study area is a part of Central Iranian zone and Urumieh-Dokhtar magmatic belt. Clinopyroxene, plagioclase and amphibole are main minerals in the pluton. Mineral chemistry studies show that clinopyroxenes are augite and are plotted in almost medium pressure field. The clinopyroxene co...
The LA-ICP-MS U-Pb method has been used to define the Palaeoarchaean (3264 ± 7 Ma) age of zircon from metarhyodacite Aleksandrovsk Suite Mykhailivka Series (the southeastern part Tim-Yastrebov structure Kursk Magnetic Anomaly (KMA)). According geochemical data, primary melt probably developed in a crustal magmatic source due melting older felsic rocks. closely resemble composition felsic, igneo...
It typically occurs as an alteration product at the contact between felsic and mafic or ultramafic rocks such as pyroxenites and dunites. It also occurs in carbonatites and metamorphosed magenesium rich limestone. Associated mineral phases include: corundum, apatite, serpentine and talc. It occurs interlayered with chlorite, biotite and phlogopite.[2] Vermiculite Wikipedia, the free encyclopedi...
In this research, petrographic and geochemical (major and trace elements) characteristics of siliciclastic rocks of the Mozduran Formation in the eastern Kopet-Dagh Basin have been carried out in order to reveal their provenance such as source area paleoweathering, parent rock composition and tectonic setting. Mozduran Formation is mainly composed of limestone and dolomite, with minor amounts o...
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