نتایج جستجو برای: ultramafic bedrock

تعداد نتایج: 4457  

2008
Jack W. Schmid

This paper is based on research experience in radon transport. Radon in homes is a serious hcalth concern in the Tanana Valley region of Interior Alaska. The authors have much research experience in this area and arc keenly interested in radon transport and dynamics for this climatic zone. The source of radon for Interior Alaska is primarily uplands metamorphic schist bedrock, which can allow r...

Journal: :Rapport Grønlands Geologiske Undersøgelse 1971

2006
A. T. V. ROTHSTEIN

TWO different spinels, analyses of which are given, occur in the layered ultramafic rocks at Dawros. Chrome spinel occurs both as gravity-stratified cumulates and as complex orbs, while an Al-rich spinel is both in rocks of the main Dawros magmatic sequence and in an association with an aluminous bronzite, which may originate by recrystallization. It is concluded that while the chrome spinel is...

2005
ANA FILIPA A. MARQUES VALERIE CHAVAGNAC YVES FOUQUET

Petrological, geochemical and Nd-isotopic analyses have been carried out on rock samples from the Rainbow vent field to assess the evolution of the hydrothermal system. The Rainbow vent field is an ultramafic-hosted hydrothermal system located on the Mid-Atlantic Ridge, characterized by vigorous high-temperature venting (~365ºC) and unique chemical composition of fluids: high chlorinity, low pH...

Journal: Geopersia 2017

Some 43 samples collected from surficial sediments of Semnan Province (Alborz zone) and NE Isfahan Province (Central Iran zone) were analyzed, for constrains on provenance. Sand fraction were analyzed by XRF analyzer Philips Model PW 2450 in the laboratory of the Geology Survey Iran (GSI). Precision was 0.01%. Furthermore, 8 selected sediment samples and 8 samples from rock units from surroundi...

The podiform chromitite deposits of the Ordovician Sorkhband ultramafic complex, southwestern Makran, are the largest chromitite deposits in Iran. The Sorkhband ultramafic complex comprises of a northern part of dunite, podiform chromitite, olivine clinopyroxenite, wehrlite and olivine websterite and a southern part of foliated diopsidic harzburgite with subordinate dunite, olivine clinopyroxen...

آفتابی, علیجان , امینی, صدرالدین , زرین‌کوب, محمد‌حسین , کریم‌پور, محمد‌حسن ,

On the basis of mineralogy and geochemistry analysis, the listvenites in east of Iran are divided into three main carbonate, silica-carbonate and silica groups. Magnesite, dolomite, huntite and hydromagnesite are the major minerals in carbonate type. Silica listvenites contain mainly quartz, chalcedony and opal. Silica - carbonate listvenites contain minerals of carbonate and silica listvenites...

kourosh Mohammadiha, mohsen Moazzen, robab Hajialioghli, U Altenberger,

The Mashhad ultramafic complex with a Permo-Triassic stratigraphic age is exposed at the NE of Binaloud Mountain and the SW to NW of Mashhad city. This area is mainly composed of mafic and ultramafic rocks, metamorphosed carbonate and pelitic rocks and granitoids in a NW- SE trend. Serpentinized amphibole-peridotites are the main types of ultramafic rocks in this area. Minerals in these rocks i...

Journal: :Earth System Science Data 2023

Abstract. Strontium isotopes (87Sr/86Sr) are useful to trace processes in the Earth sciences as well forensic, archaeological, palaeontological, and ecological sciences. As very few large-scale Sr isoscapes exist Australia, we have identified an opportunity determine 87Sr/86Sr ratios on archived fluvial sediment samples from low-density National Geochemical Survey of Australia. The present stud...

2006
MICHAEL A. WALL ROBERT S. BOYD

Nickel hyperaccumulator plants contain at least 1,000 mg Ni/g dry mass. Their high-Ni tissues present a chemically unique resource for herbivorous insects. A prior survey of insects associated with the Ni hyperaccumulator Streptanthus polygaloides in California yielded a new species, Melanotrichus boydi Schwartz and Wall (Hemiptera: Miridae). Here we document the host preference of M. boydi. Su...

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