نتایج جستجو برای: collision volcanic rocks
تعداد نتایج: 81746 فیلتر نتایج به سال:
miocene silisiclastic sediments in binalood zone consist of three lithofacies group including gravelly (gmm, gcm, gci, gh, gt, gp), sandy (st, sm, sh, sp, ss, sl) and muddy (fm, fl). gravelly lithofacies are generally massive and mainly consist of volcanic and sedimentary lithic in different size. sandy lithofacies are composed of litharenite and feldespathic volcanicarenite and rock fragments ...
Petrography and chemistry of minerals showing that Eocene alkaline volcanic rocks in southwestern of Germi (Talesh zone, NW Iran) mostly have basaltic composition. Mineralogically these rocks are composed of diopsidic clinopyroxene and labradoritic plagioclase phenocrysts. The microlithic and glassy groundmass composed of sanidine, clinopyroxene, biotite, pargasitic amphibole and magnetite asso...
Crustal assimilation (e.g. Hildreth and Moorbath, 1988) and/or subduction erosion (e.g. Stern, 1991; Kay et al., 2005) are believed to control the geochemical variations along the northern portion of the Chilean Southern Volcanic Zone. In order to evaluate these hypotheses, we present a comprehensive geochemical data set (major and trace elements and O–Sr–Nd–Hf–Pb isotopes) from Holocene primar...
The Esfezar bentonite deposit is located 50 km east of Birjand, in south Khorasan Province and as a part of eastern boundary of lut Block. This deposit is a diagenetic bentonite type, because of its layering, existence of gypsum between bentonite layers, and expanded shape. Petrography and chemical analysis of host rocks in Esfezar bentonite deposit indicate that they are mainly of dacite and ...
logues rocks during entry into the Earth’s atmosphere F. Foucher, F. Westall , J.-M. Bény , F. Brandstätter , and R. Demets , 1 Centre de Biophysique Moléculaire, UPR CNRS 4301, Orléans, France ([email protected]), 2 Institut des Sciences de la Terre d’Orléans, UMR CNRS 6113, Orléans, France, 3 Naturhistorisches Museum, Burgring 7, 1010 Wien, Austria, 4 European Space & Technolog...
Hamyerd iron deposit is located about 74 km north east of Semnan, in the Jam area. This area is situated in the northern part of Central Iran structural zone. The outcrops are Middle-Eocene volcanic and pyroclastic rocks with andesite to andesite-basalt and tuff composition, which are intruded by some intrusive bodies of monzonite to monzodiorite composition in this area. Iron mineralization is...
Newly discovered xenoliths within Pliocene and Quaternary intermediate volcanic rocks from southern Peru permit examination of lithospheric processes by which thick crust (60–70 km) and high average elevations (3–4 km) resulted within the Altiplano, the second most extensive orogenic plateau on Earth. The most common petrographic groups of xenoliths studied here are igneous or meta-igneous rock...
bentonite deposits of economic interest are widespread in tashtab mountains (khur), east of isfahan province, iran. several bentonite deposits have been developed in this area as a result of eocene volcanic alteration. these deposits are classified as khur bentonite horizon. xrd analyses reveal that alteration products consist of na-montmorillonite, kaolinite, quartz, calcite, and crystobalite....
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