نتایج جستجو برای: thermobarometry
تعداد نتایج: 187 فیلتر نتایج به سال:
The structural and thermal relaxation overprint associated with the Neogene Alboran rifting have obscured early Alpine tectono-metamorphic evolution of Domain, representing metamorphic core Betic–Rif orogen western Mediterranean region. This study focuses on Beni Mzala unit, forming lower deeper level nappe stack (Upper Sebtides) in Moroccan Rif. Meso- micro-scale investigations are carried out...
1- Introduction The studied area is situated in northeast Varzeghan in East Azerbaijan Province. In the classification of the structural unites of Iran, this area is a part of Ahar-Arasbaran magmatic arc. The Cenozoic magmatism in the Ahar–Arasbaran region started in the Eocene with an intensive volcanic activity that produced widespread basic to felsic rocks and continued in the Oligo-Miocene...
The Nokeh intrusion exposed in the northern Semnan area. The intrusion is composed of monzonite-quartz monzonite and granite-granodiorite and was intruded in the Eocene carbonaceous tuffs, where the country rocks converted to magnetite-skarn. Plagioclase, orthoclase, quartz, biotite, amphibole and clinopyroxene are the constituent minerals of Nokeh intrusion. The study rocks represent granular,...
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...
The Central Asian Orogenic Belt was characterized by a long-lived accretionary history from Neoproterozoic to Paleozoic, followed collisional phase of orogeny in the latest Paleozoic with closure Paleo-Asian Ocean. However, Ni-Cu sulfide mineralization associated mantle-derived mafic magmas relatively short-lived. Thus, coherence between protracted and transient sulfide-bearing magmatism is dif...
Abstract The last four caldera-forming ignimbrites in the central San Juan caldera cluster, Colorado, erupted 1400 km3 ≤80 kyr and alternated between zoned crystal-poor rhyolite to crystal-rich dacite unzoned, dacite. 150 Rat Creek Tuff (26·91 Ma), unzoned 250 Cebolla Tuff, 500 Nelson Mountain (26·90 Ma) formed nested Luis complex with slightly offset calderas, Snowshoe (26·87 Creede south. hav...
The relations between Barrovian- and Buchan-type metamorphic series in the Chinese Altai remain obscure, hence a representative region of central part was investigated to address this issue, using combined microstructural, petrological geochronological methods. In region, Barrovian-type garnet, staurolite, kyanite sillimanite zones are locally overprinted by andalusite- cordierite-bearing domai...
Abstract The cratonic lithosphere–asthenosphere boundary is commonly invoked as the site of sheared peridotite and megacryst formation, a well-recognized petrological assemblage whose genetic relationships—if any—remain poorly understood. We have undertaken comprehensive petrology Sr–Nd–Hf–Ca isotope study xenoliths clinopyroxene megacrysts from c. 1150 Ma Premier kimberlite pipe on central Kaa...
Abstract Two suites of amphibole-rich mafic–ultramafic rocks associated with the voluminous intermediate to felsic in Early Cretaceous Laiyuan intrusive–volcanic complex (North China Craton) are studied here by detailed petrography, mineral and melt inclusion chemistry, thermobarometry demonstrate an situ reaction-replacement origin hornblendites. Moreover, a large set compiled newly obtained g...
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