نتایج جستجو برای: mafic composition
تعداد نتایج: 261231 فیلتر نتایج به سال:
Hasht-Sar Kaleybar mafic, ultramafic and syenitic dykes are surrounded by Majid Abad Formation, Palaeocene age, volcanic deposits. The suite is restricted within the Horand, Mahmud Abad and Mokhtekan thrust and reverse faults. Clinopyroxenites, the oldest unit of the suite, have tholeiitic volcanic arc character and have some similarities with tectonite layer of oceanic crust, like Group A pyro...
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...
The Darvazeh-Chenar mafic- ultramafic body is part of ophiolitic complex of Neyriz in Fars Province that formed in association with closing of Neo-Tethys Ocean and Arabian- Iranian plate collision in Cretaceous. The Faryab ophiolitic rocks are also remnant of block of Tethys oceanic crust that were obducted on continental margins in late Cretaceous period. MgO, Fe2O3, Al2O3, Cr2O3 and TiO2 cont...
At the base of Shemshak Formation in the south Azadshahr area, some igneous mafic rocks are discovered recently as olivine gabbro bodies and pegmatoid alkali-diorite dikes. Rock-forming minerals of olivine gabbro includes olivine, clinopyroxene and plagioclase, alkali-diorites are composed of large amphiboles and plagioclase. Major and trace elements characteristics of these rocks indicate the...
Melting of mafic veins in a marble-cake mantle may play an important role in generating isotopic and chemical heterogeneities in mid-ocean ridge and ocean island basalts. Mafic veins have lower solidi than mantle peridotite and will be preferentially sampled during partial melting, particularly at low melt fractions. However, the abundance of mafic components in the mantle or their role during ...
Introduction: Grains of composition with Fe, Ni and Cl are reported as relicts of awaruite (in mafic minerals of olivine and serpentine from the interior of the Earth) [1] or meteoritic mixture found originally at the fusion crust melted in atmosphere [2, 3, 4]. Recently author (YM) discusses that carbon contents of these phases are significant to discuss the sources of Fe, Ni and Cl [2, 3, 4, ...
The central region of the mainland Lewisian gneiss complex of NW Scotland is a granulite-facies migmatite terrane.With the exception of ultramafic and rare calc-silicate rocks, all other lithologies partially melted during Neoarchaean, ultrahigh-temperature (Badcallian) metamorphism. The clearest evidence is preserved within large layered mafic^ultramafic bodies that exhibit macroscopic feature...
Approximately 90% of the upper crust exposed in southern Jordan is composed of intrusive rocks of latest Neoproterozoic age, grouped into two major subdivisions: the Aqaba (600–640 Ma) and the Araba (560–600 Ma) complexes. The Aqaba complex comprises several suites that range in composition from gabbro to high silica granite (45–80% SiO2) and follow a high-K calc-alkaline trend. This phase, whi...
Mafic enclaves from three plutons in the Chilliwack batholith have been compared with contemporaneous mafic stocks in order to determine (1) the processes by which mafic and felsic magmas hybridize in the plutonic environment and (2) whether analysis of early-formed enclave minerals, particularly apatite, can provide a means of seeing through hybridization effects and deciphering the original t...
The Ok Tedi Complex hosts a world-class porphyry copper-gold deposit. Samples from the Ok Tedi Complex and the neighbouring Mount Ian Complex were analyzed for major and trace elements using XRF and HR-ICP-MS, and the isotopic composition of S in sulphides was analyzed by Elemental Analyzer. Major element geochemistry indicates that both complexes are alkaline and contain rocks ranging in compo...
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