نتایج جستجو برای: ophiolite

تعداد نتایج: 1054  

2002
Hans Schouten Peter B. Kelemen

The lava section in the Troodos ophiolite, Cyprus, is chemically stratified and divided into a shallow lava sequence with low TiO2 content and a deeper lava sequence with high TiO2 content. We calculate the viscosity at magmatic temperature based on major element chemistry of lavas in Cyprus Crustal Drilling Project (CCSP) Holes CY-1 and 1A. We find that typical shallow low-Ti lavas have a magm...

Journal: :Science 2007
Warren B Hamilton

The claim by Furnes et al. (Reports, 23 March 2007, p. 1704) that Greenland metavolcanic rocks require Paleoarchean sea-floor spreading is incompatible with their own data. The purported sheeted dikes have the composition of pyroxenitic komatiite and could not have fed the adjacent ferroandesitic pillow lavas. Neither type has ophiolitic analogs, and both are likely ensialic.

Journal: :Frontiers in Earth Science 2021

Nickel isotope fractionation patterns in continental ultramafic environments generally show a depletion of δ 60 Ni weathered rocks and an enrichment bedrock samples. The present study focuses on stable carbonate-rich, ophiolite samples with concomitant fluids at active serpentinization site southwestern Turkey, comparison to results from inactive the Eastern Desert Egypt carbonate-rich All soli...

Journal: :Geophysical Research Letters 2021

The Great Serpentinite Belt of eastern Australia is a ∼1500 km long dismembered ophiolite assumed to be Cambrian based on studies small (typically <50 m2) exotic meta-igneous inclusions despite contrasting ages (Cambrian—Devonian) and complex P-T histories. To overcome these issues, we studied ∼18 km2 coherent block that provides robust geological context sampling the ophiolite. Zircon U-Pb-Hf-...

Journal: :Iraqi geological journal 2022

New geochemical data were presented for the mafic (basalts and gabbros) ultramafic (dunites, serpentinites pyroxenites) rocks from Mawat ophiolite exposed in Zagros suture zone northeastern Iraq. The mantle section of is composed serpentinized peridotites, harzburgites, dunites, chromitites pyroxenite dykes. crustal layered amphibole-rich gabbros, pegmatitic gabbros as well basalts minor felsic...

احمد, احمدحسن, ترابی, قدرت, آرایی, شوجی , سبزه‌یی, مسیب , شیراساکا, میکی ,

In the upper Proterozoic Anarak ophiolite, the marbles are present and havr excellent exposures in different areas. Their best exposure is in southern slope of Chah-Gorbeh mountain (Chah-Mahdi valley). In the field, marbles have massive and dike like exposures. Petrographic studies and geochemistry of minerals show that marbles consist of carbonate (calcite), garnet (andradite), clinopyroxene (...

Journal: :زمین شناسی اقتصادی 0
محمد حسین زرین کوب سون لین چانگ سید سعید محمدی محمد مهدی خطیب

bibi maryam granitoid body with about 5 km2 has intruded into ophiolite mélange complex in sistan suture zone, in east of iran. thermal effects of this body on the host rocks show that this activity occurred after emplacement of ophiolite mélange. this intrusive body with general northwest – southeast trend is mainly tonalite-quartz diorite but there is a minor unit as dykes of granodiorite in ...

مرادپور, علی, زارعی سهامیه, رضا ,

Ophiolites of the Zagros orogenic belt are part of the Tethys ophiolites, because of their geographical locations and link the Middle East ophiolites and other Asian ophiolites (e.g. Pakistani and Tibetan) to the Mediterranean ophiolites (e.g. Troodos , Greek and East European). The nature of the Harsin- Sahneh ophiolite (Kermanshah) traditionally identified as one of the Mesozoic southern bran...

Journal: :journal of tethys 0

the serpentinization of the harzburgitic mantle section of the bou azzer neoproterozoic ophiolite is studied by field mapping, structural observations, optical micrography, sem and x-ray diffractometry, and relationships with co, ni, cr and sulphides minerals are discussed. serpentinization occurred in two major steps with, i) intra-oceanic pseudomorphic serpentinization materialized by the iso...

Journal: :iranian journal of science and technology (sciences) 2015
m. a. rajabzadeh

biogeochemical investigation on s. orientalis, a flora growing on the soils derived from serpentinized dunite in the forumad area, sabzevar ophiolite has been conducted in order to examine the plant-soil relationship in chromite prospecting. due to engagement of cr in the chromite crystal structure and its non-essential role in the plant’s life cycle, ni was used as pathfinder element in biogeo...

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