نتایج جستجو برای: ophiolite
تعداد نتایج: 1054 فیلتر نتایج به سال:
Chromitite lenses rich in the platinum-group elements (PGE) have recently been discovered in the deeper part of the mantle section of the northern part of the Oman ophiolite. In terms of stratigraphic level, there are two types of chromitite: Moho transition zone (MTZ) and mantle types. The mantle type can be further classified into two subtypes: PGE-poor and PGE-rich. Platinum-group minerals (...
Mafic–ultramafics complexes are crucial for their tectonic implication, upper mantle condition, and hosting industrial minerals in a region. This study aims to highlight characterize the mafic–ultramafic rocks of Logar Ophiolite Complex using integration geospatial technology field data. The spatial distribution ophiolitic complex was examined this mineralogical indices (MI), band ratio (BR), s...
The tectonic significance of the Muness Phyllite, which overlies Unst–Fetlar ophiolite in Shetland, Scottish Caledonides, is poorly understood. U–Pb analyses detrital zircons show that it was deposited after c . 469 Ma. Early Paleozoic grains have εHf values −0.3 to +12.3 and were probably derived from extension Midland Valley arc. Psammite clasts matrix Phyllite contain Proterozoic Archean wit...
Furnes et al. (1) reported that a sheeted-dike complex they identified within the ~3.8billion-year-old Isua supracrustal belt (ISB) in Greenland provides the oldest evidence of oceanic crustal accretion by spreading. However, they did not alert readers that the ISB contains supracrustal rocks and mafic dikes of different ages (2, 3). They also failed to demonstrate that the proposed components ...
Abstract The punctuated distribution of major gold deposits along orogenic belts is poorly understood. In northern Perú, cluster trends that transect the subparallel Phanerozoic accreted onto western margin Archean–Proterozoic Amazonian craton. This suggests influence as yet unrecognized pre-Andean basement structures in controlling localization deposits. We report newly discovered Tomac ophiol...
Abstract New zircon U-Pb geochronology from a peridotite suite near Ranau and the Telupid ophiolite in Sabah, eastern Malaysia, contradict previous studies, which assumed that Sabah mafic-ultramafic rocks are largely ophiolitic Jurassic–Cretaceous age. We show these formed during magmatic episode Miocene (9.2–10.5 Ma), is interpreted to reflect infiltration of melts melt-rock reaction subcontin...
افیولیت بیبی مریم بخشی از مجموعه افیولیتی نهبندان، به سن کرتاسه، در بخش شمالی پهنه گسلی نهبندان، شرق ایران، است. سنگ های مافیک این مجموعه شامل بازالت، دیاباز و گابرو هستند. نبود سنگهای دگرگونی رخساره شیستسبز، شیستآبی و آمفیبولیت، فقدان سنگهای کومهای پریدوتیتی با وجود فراوانی پریدوتیتهای گوشتهای، عدم مشاهده گابروی کومهای علیرغم فراوانی گابروی ایزوتروپ، نبود دسته دایکهای دیابازی به صور...
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