نتایج جستجو برای: metasomatized mantle
تعداد نتایج: 16941 فیلتر نتایج به سال:
We identified a ca. 180 Ma diamondiferous lamproite event in Zambia, establishing link between ultrapotassic volcanism and the early Jurassic Karoo flood basalt province of sub-Saharan Africa. The cratonic lamproites erupted through Permo–Triassic Luangwa Rift structure, but MgO-rich magma formation was unrelated to rifting triggered by plume–lithosphere interactions during LIP event. Elevated ...
Ultramafic xenoliths from southeastern Arizona, USA, provide evidence for Cu-isotope heterogeneity in the lithospheric mantle. We report new data on Type I (Cr-, Mg-rich) peridotites, but also first Fe-Ti-Al-rich II pyroxenite (±amphibole) xenoliths. Whole rock ?65Cu values of pyroxenites and cryptically metasomatized lherzolites range to isotopically heavier compositions than asthenospheric ma...
Nosrat-Abad ophiolitic extrusive sequence, located in the Sistan Suture Zone, in south eastern Iran. The extrusive sequence, contains pillow lava, sheet flow and related volcanic-clastic breccias which have undergone low-grade metamorphism. This association shows calc alkaline to tholeiitic affinities. Interpretation of the geochemical data and behavior of the elements in different diagrams rev...
Trachyandesites, trachytes and latites associated with ignimbrite and pyrocalstic rocks, characterized by shoshonitic affinity are the main Plio-Quaternary volcanic rocks in the Sabalan region (Ardabil). Plagioclase, K-feldspar, biotite associated with clinopyroxene and glass are the main constituents of these lavas. Plagioclases are andesine to labradorite while clinopyroxenes have augitic com...
Dioritic plutons and pinkish alkali-feldspar granitic dikes of Kalateh area (northwest of Khur city) intruded in Neoproterozoic basemental of Jandagh- Arousan complex. Field observations, petrography and geochemical studies indicate that these intrusive rocks have I-type nature and belong to medium-high K calc-alkaline granitiods and also have genetically relationship with each other. Their par...
In southwest of the Jandaq City (northeast of Isfahan Province) and northwest of the Central-East Iranian Microcontinent (CEIM), the Eocene dykes with trachy-andesitic composition cross cut the quartz monzodioritic intrusion. The texture of these dykes is granular, intergranular and porphyritic. The studied dykes are composed of plagioclase (andesine and labradorite), clinopyroxene (diopside an...
The Bayazeh ophiolite, with Paleozoic age, is located in the eastern margin of the Yazd Block (Central Iran). This ophiolite consists of serpentinized peridotites, metagabbro, ultrabasic metamorphosed dikes, metapicrite, serpentinite and metalistvenite. Rock forming minerals of the metapicrites in the Bayazeh ophiolite are olivine (completely altered to serpentine), clinopyroxene (diopside, aug...
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