نتایج جستجو برای: pyroxene group

تعداد نتایج: 980267  

Journal: :The Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists 1980

1999
Paul C. Buchanan Christian Koeberl Wolf Uwe Reimold

The Precambrian Dullstroom Formation of South Africa, which is predominantly composed of basaltic andesites interbedded with subordinate sedimentary and felsic volcanic strata, represents the ®rst phase of an extended period of magmatism that was responsible for the Bushveld Magmatic Province, including the extrusive Rooiberg Group and the intrusive Bushveld Complex. New geochemical and isotopi...

Journal: :Volcanica 2022

We present Thermobar, a new open-source Python3 package for calculating pressures, temperatures, and melt compositions from mineral mineral-melt equilibrium. Thermobar allows users to perform calculations with >100 popular parametrizations involving liquid, olivine-liquid, olivine-spinel, pyroxene only, pyroxene-liquid, two pyroxene, feldspar-liquid, feldspar, amphibole amphibole-liquid, gar...

2003
G. McKay

Introduction: Shock metamorphism is one of the most fundamental processes in the history of Martian meteorites. Especially, shergottites experienced strong shock effects (>30 GPa) most likely when they were ejected from Mars [e.g., 1]. " Maskelynitization " of plagioclase and formation of shock melts are major effects due to this severe shock. QUE94201 (QUE) and Dhofar 378 (DHO) are basaltic sh...

2009
M. J. Wick

Introduction: Primary igneous plagioclase is found in approximately 10 % of type I chondrules in CO chondrites [1]. The presence of plagioclase has potential to help interpret conditions of chondrule formation, if the conditions of plagioclase nuclea-tion and growth are understood. Because primary plagioclase typically contains a significant albite component, the presence of this mineral is sig...

2012
Michael Andrew Feierberg

High-resolution Fourier spectra in the 0.9-2.5 ym region were measured for sixteen asteroids. These data were combined with 0.3-1.1 um spectrophotometry and 3.0-3.5 urn narrowband photometry for compositional analysis. Comparison spectra of meteorites and terrestrial minerals were measured in the laboratory, some under simulated asteroidal conditions of pressure and temperature. Spectra of elev...

2007
Shaye Storm

The mineralogical composition of asteroids can be constrained using visible and near-IR (VNIR) spectroscopy. The most prominent spectral features observed over this wavelength range are due to olivine and pyroxene, the two most abundant minerals in both chondritic and achondritic meteorites. The observed ratio of these two minerals is highly dependent on the amount of heating that an asteroid h...

2006
E. Koizumi T. Mikouchi J. Chokai

Introduction: Only 5 meteorites were classified into unbrecciated lunar mare basalt so far, although there are about 40 lunar meteorites known to date. NWA 032 and its paired meteorite NWA 479 (NWA) are such crystalline mare basalts, and show a porphy-ritic texture composed of euhedral olivine and pyrox-ene grains with dendritic mesostasis of pyroxene, pla-gioclase and accessory minerals (ilmen...

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