نتایج جستجو برای: gneiss
تعداد نتایج: 648 فیلتر نتایج به سال:
In this study, data from garnet-kyanite metapelites in ultrahigh-pressure (UHP) domains of the Western Gneiss Region (WGR), Norway, are presented. U–Pb geochronology and trace element compositions zircon, monazite, apatite, rutile garnet were acquired, pressure–temperature (P–T) conditions calculated using mineral equilibria forward modelling Zr-in-rutile thermometry. Garnet-kyanite gneiss Ulst...
The higher rate of slope erosion in the Himalayan basins is contributing to rapid change landform mountainous terrain, which has caused sedimentation, and inundation downstream. Tamakoshi basin a trans-boundary river that originates from Tibet flows through Dolakha Ramechap districts before joining Sapta Koshi river. Few studies exist Nepal attempting quantify susceptibility. However, they are ...
A net of pegmatite veins crosscut gneiss and dismembered ophiolitic ultramafic rocks are abundant in the Migif-Hafafit culmination area, South Eastern Desert, Egypt. Some these pegmatites corundum-bearing. Corundum-bearing studied eight localities around complex. The present study aims to integrate field investigation, whole rock corundum chemistry, remote sensing studies, conventional methods ...
Both single and multigrain U-Pb zircon thermal ionization mass spectrometry (TIMS) as well as sensitive high resolution ion microprobe (SHRIMP ll) dating of two suites of Adirondack granites have yielded ages constraining the principal tectonomagmatic events of the Ottawan Orogeny to the interval ca 1090–1035 Ma. The earliest of these consists of mildly A-type hornblende granites of the Hawkeye...
Oceanic plateaus form by mantle processes distinct from those forming oceanic crust at divergent plate boundaries. Eleven drillsites into igneous basement of Kerguelen Plateau and Broken Ridge, including seven from the recent Ocean Drilling Program Leg 183 (1998^99) and four from Legs 119 and 120 (1987^88), show that the dominant rocks are basalts with geochemical characteristics distinct from ...
With proven reserves of 9.836 × 1010 m3, the largest known natural gas reservoir among terrigenous basement rocks has been discovered within granitoids northern Qaidam Basin. Due to their high heterogeneity, genesis reservoirs remains unknown. Herein, structure weathering crust in and potential controlling factors on development mechanism are discussed using a multidisciplinary approach based d...
The mechanics and petrological signature of a collisional mountain belt can be significantly influenced by topographic and erosional effects at the scale of large river gorges. The geomorphic influence on crustal scale processes arises from the effects of both stress localization due to existing topography, and also erosional removal of advected crustal mass. The shear stress concentration and ...
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