نتایج جستجو برای: mafic magma

تعداد نتایج: 8846  

2006
Federica Raia Frank J. Spera

There is overwhelming and incontrovertible petrological and geophysical evidence for the significant role played by mantle-derived mafic magma in the generation and growth of continental crust. Likewise, intrusion of mafic magmas beneath or into continental crust is very likely the major source of enthalpy that drives intracrustal differentiation. A simple dynamical model has been constructed t...

2010
M. E. Gharib M. A. Obeid

Older and younger granitoids are widespread throughout the basement rocks of NE Egypt. Therefore, they are played a significant role in the evolution of the Pan-African crust. The Wadi El Sheikh-Gabal Saint Katherine area comprise three distinctive magmatic granitoid suites, namely: (1) calc-alkaline older quartz monzodiorite-tonalite suite (COG), (2) calcalkaline younger monzogranite suite (CY...

2016
Shichun Huang Munir Humayun

The role of a mafic component in the petrogenesis of Oceanic Island Basalts (OIBs) is highly debated. As the best studied OIB, Hawaiian lavas provide critical insights into OIB genesis. At a given MgO content, the CaO content in the melt has been used to distinguish between partial melts of peridotite and garnet pyroxenite/eclogite. However, calculations using the BATCH program show that CaO co...

2017
Diane R. Smith William P. Leeman

Smith, D. R. and Leeman, W. P., 1993. The origin of Mount St. Helens andesites. J. Volcanol. Geotherm. Res., 55: 271-303. Mount St. Helens volcano has intermittently produced mainly dacitic products but occasionally erupted a more diverse suite of lavas including basalts and andesites. Petrogenetic relations between these magmas provide insight into the dynamics of the subjacent magma system. M...

2007
S. S. HUGHES

Multi-element abundances in twenty-four samples from the Serra Geral continental flood basalt system (Parana Basin) were determined by INAA to assess the trace element signature of primary magmatric sources. Isotopic Sr and Nd data were obtained on a 24-sample composite and three individual samples of the suite to constrain the influences of older enriched material. Twenty basaltic samples have...

2012
J. R. Skok J. F. Mustard L. L. Tornabene C. Pan D. Rogers S. L. Murchie

[1] The earliest formed crust on a single plate planet such as Mars should be preserved, deeply buried under subsequent surface materials. Mars’ extensive cratering history would have fractured and disrupted the upper layers of this ancient crust. Large impacts occurring late in Martian geologic history would have excavated and exposed this deeply buried material. We report the compositional an...

2011
Bradley R. Hacker Peter B. Kelemen Mark D. Behn

a r t i c l e i n f o Crust extracted from the mantle in arcs is refined into continental crust in subduction zones. During sediment subduction, subduction erosion, arc subduction, and continent subduction, mafic rocks become eclogite and may sink into the mantle, whereas more silica-rich rocks are transformed into felsic gneisses that are less dense than peridotite but more dense than the uppe...

2009
Clément Ganino Nicholas T. Arndt Fabrice Gaillard Catherine Chauvel

Interaction of magma with sedimentary wall rock and magnetite ore genesis in the Panzhihua mafic intrusion, SW China Clément Ganino , Nicholas T. Arndt , Mei-Fu Zhou , Fabrice Gaillard and Catherine Chauvel Laboratoire de Géodynamique des Chaînes Alpines, Université Joseph Fourier de Grenoble, CNRS, 1381 rue de la piscine 38400 Saint Martin d’Hères, France Department of Earth Sciences HKU, Pokf...

ژورنال: :پژوهش های دانش زمین 0
نوشین صابرشهرکی دانشگاه سیستان و بلوچستان علی احمدی دانشگاه سیستان و بلوچستان مصطفی قماشی دانشگاه سیستان و بلوچستان

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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