نتایج جستجو برای: pyroxene group

تعداد نتایج: 980267  

2009
M. Anand J. Parkinson

Introduction: The zoning patterns of light lithophile elements (LLEs: Li, Be, B) in pyroxenes of some Martian meteorites have been used to suggest that the parent basalts were water-saturated, which exsolved and lost an aqueous phase through degassing and eruption, causing depletion in LLEs in the pyroxene rims [1]. In contrast, other investigators have suggested a diffusion controlled fraction...

Bagheri, , Bahramnejad, , Zahedi, ,

The Deh-Salm Metamorphic Complex (DMC) is composed of metapelite, metabasite, metaperidotite, and calc-silicate rocks and is one of the few outcrops of the Lut block’s basement which emerged near to the Sistan suture zone. In the eastern part of the Deh-Salm metamorphic complex, the calc-silicate and marble appeared in the form of elongated tectonic lenses that have been metamorphosed in simila...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2003
Karim Benzerara Nicolas Menguy Francois Guyot Christian Dominici Philippe Gillet

Nanobacteria-like objects evidenced at the surface of the orthopyroxenes of the Tataouine meteorite in South Tunisia have been studied by scanning and transmission electron microscopies. A method of micromanipulation has been developed to ensure that exactly the same objects were studied by both methods. We have shown that the nanobacteria-like objects are spatially correlated with filaments of...

Journal: :Journal of Petrology 2021

Abstract Drilling related to development of the platinum-group element deposit J-M Reef Stillwater Complex returned samples a rare chromitite seam between anorthosite and norite in discordant anorthositic body. Plagioclase core An concentrations are marginally higher modestly reversely zoned on side (average Ancore = 83·8; average – Anrim –1·1) as compared with 82·5; +1·0). The anorthosites als...

2013
S. B. Simon L. Grossman

Introduction. The Wark-Lovering rims [1] found on many refractory inclusions are important recorders of nebular environments to which refractory inclusions were exposed after their formation, such as different temperature regimes and isotopic reservoirs [2]. As part of a large-scale survey of W-L rims to enable us to better understand the range of environments reflected in rims, an inclusion of...

2009
M. Kimura A. El Goresy T. Mikouchi A. Suzuki M. Miyahara

Introduction: Ca-Tschermak (hereafter CaTs), CaAl 2 SiO 6 , component has been one of the most important hypothetical members of pyroxene, and CaTs-rich pyroxene was abundantly reported from refractory inclusions in carbonaceous chondrites [e.g., 1]. However, the nature of such pyroxene has not been characterized in detail because of their tiny grain size. For the first time, we succeeded to id...

2006
A. N. Krot

Introduction: The metal-rich CH and CB chondrites are among the most primitive (unmetamorphosed, unaltered), but controversial meteorites: both nebular and asteroidal models have been proposed to explain the origins of their components [1-14]. In addition to porphyritic chondrules and rare refractory inclusions, the CHs contain a high abunbance (~20 vol%) of metal and dominant cryptocrystalline...

Mantle peridotites exposed in south Jazmourian comprise of lherzolite and porphyroclastic Cpx-bearing harzburgite in the lower part with chromitite lenses in the upper parts. Petrography and microprobe studies shows evidence of melt-peridotite interactions; post melting processes and subsolidus interactions, which has been associated with appearance of two generations of deformed primary pyroxe...

Journal: :Journal of Nepal Geological Society 2023

In the last few decades, for estimation of original equilibrium conditions mantle and deep crustal rocks, several empirical as well synthetic thermometers have been proposed. Various types rocks from earth, moon or meteorites contain two coexisting pyroxenes. Petrologists long recognised potential high Ca low pyroxenes to yield thermometric calculations. Several models proposed pyroxene in deca...

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