نتایج جستجو برای: metasomatism
تعداد نتایج: 517 فیلتر نتایج به سال:
The plutonic complex in SE Jersey consists of a late Precambrian gabbro-diorite mass which has been intruded by several granites. The status of the diorites which, like the gabbros, often possess a layered structure, is not clear. New geochemical data, including rare earth and trace element analyses, suggest that acid-basic magma mixing was not responsible for the variety of intermediate rocks....
In the Cheshmeh-Bid district of Khajeh-Jamali ophiolitic massifs (Southern Iran), mantle peridotites are intruded by abundant pyroxenite dykes. A few these dykes remarkable for occurrence native copper associated with development a metasomatic reaction zone. The progressively reacted, from their margins towards center, an amphibole + antigorite selvage, followed centimeter-thick clinopyroxene a...
Based on hyper spectral data mining techniques, field spectra data is used to study the diagnosable spectral signatures of uranium mineralization factors in this paper, and the spectral features of pluton, ore-controlling fault and hydrothermal alteration including alkali metasomatism, hematitization, chloritization and hydromicazation are acquired and analyzed, the diagnosable spectra identifi...
Subduction zones play critical roles in the recycling of oceanic lithosphere and the generation of continental crust. Seismic imaging can reveal structures associated with key dynamic processes occurring in the upper-mantle wedge above the sinking oceanic slab. Three-dimensional images of reflecting interfaces throughout the upper-mantle wedge above the subducting Tonga slab were obtained by mi...
A common perception among petrologists is that Al is immobile in most geologic processes, and, therefore, the conversion of gabbro with high Al-content (16-18 wt. % Al2O3) to granitic rocks with lesser Al-content (12-13 wt. % Al2O3) by Kand Si-metasomatism is not possible. The mobility of Ca, Mg, and Fe is not doubted in hydrothermal fluids, but Al is thought not to be mobile. Two different ter...
Mantle-derived xenoliths brought to the Earth’s Surface by basalts are important windows to understand composition, evolution and processes of the lithospheric mantle. The lithosphere of the southeastern China is dominated by peridotite or lherzolite [1, 2]. The spinel peridotite xenoliths studied are from Fangshan basalt, eastern China, which are composed of olivine, clinopyroxene, orthopyroxe...
Introduction: The source and duration of the heating event responsible for eucrite metamorphism is not well constrained. Three hypotheses have been proposed for the source of heat: Impact, conduction from the mantle, and rapid production of successive flows [1]. Textural and chemical relationships of noncumulate eucrites are investigated to constrain the thermal and temporal conditions responsi...
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