Results 151 to 160 of about 517 (188)
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Jadeite formation in shocked ordinary chondrites
Earth and Planetary Science Letters, 2013Abstract Albitic feldspar in shocked ordinary chondrites (Yamato 791384 L6 and Yamato 75100 H6) and albite recovered from static high-pressure and high-temperature synthetic experiments ( Kubo et al., 2010 ) were investigated with a transmission electron microscope (TEM) subsequent to a conventional micro-Raman spectroscopy analysis to clarify albite
Masaaki Miyahara +8 more
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Crystallization of chondrules in ordinary chondrites
Geochimica et Cosmochimica Acta, 1980Abstract The process of crystallization and the origin of chondrules are discussed, in terms of the phase relations of the minerals in chondrules in six ordinary chondrites of the Yamato-74 meteorites, especially the Yamato-74191 (L3). Chondrules are classified into six types.
Makoto Kimura, Kenzo Yagi
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Metallic copper in ordinary chondrites
Meteoritics, 1994Abstract— Metallic Cu of moderately high purity (∼985 mg/g Cu, ∼15 mg/g Ni) occurs in at least 66% of ordinary chondrites (OC) as heterogeneously distributed, small (typically ≤20 μm) rounded to irregular grains. The mean modal abundance of metallic Cu in H, L and LL chondrites is low: 1.0 to 1.4 × 10−4 vol%, corresponding to only 4–5% of the total Cu ...
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Accretion of the ordinary chondrites
Earth and Planetary Science Letters, 1976Abstract The narrow size distributions of silicate and metal particles in 19 unequilibrated ordinary chondrites and other textural properties of these meteorites strongly suggest that chondritic material was sorted before or during its accumulation in parent bodies.
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Terrestrial microfossils in Antarctic ordinary chondrites
Meteoritics & Planetary Science, 1999Abstract— Microfossils have been separated and identified in four high metamorphic grade chondrites from Allan Hills and Queen Alexandra Range, Antarctica. Diatoms and opal phytoliths representing both marine and terrestrial flora were recognized among the dust removed from cracks in all meteorites studied.
Lloyd H. BURCKLE, Jeremy S. DELANEY
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Matrix textures in unequilibrated ordinary chondrites
Earth and Planetary Science Letters, 1977Abstract High-voltage electron microscope observations are reported for specimens of the meteorites Hedjaz, Parnallee, Chainpur and Weston. Clastic matrix in Weston and Chainpur is distinguished from non-clastic material found in the other two specimens and in dark rims around chondrules in Chainpur.
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Nitrogen isotopes in bulk ordinary chondrites
Geochimica et Cosmochimica Acta, 1995Nitrogen isotopic compositions of twenty-one ordinary chondrites were measured using a stepwise combustion technique. We observed a good correlation between the abundances of cosmogenic15N and cosmogenic 38Ar. We obtained a relationship between the abundances of these two cosmogenic nuclides as follows: 15Nc(atoms/g) = (16.0 ± 3.7) ·38Arc(atoms/g ...
Ko Hashizume, Naoji Sugiura
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Oxygen isotope studies of ordinary chondrites
Geochimica et Cosmochimica Acta, 1991Several stages in the evolution of ordinary chondritic meteorites are recorded in the oxygen isotopic composition of the meteorites and their separable components (chondrules, fragments, clasts, and matrix). The whole-rock isotopic compositions reflect the iron-group of the meteorite (H, L, or LL).
Robert N Clayton +3 more
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Significance of the unequilibrated ordinary chondrites
Journal of Geophysical Research, 1965Olivine compositions of thirteen olivine-hypersthene and olivine-bronzite chondrites, chosen for their apparent freedom from recrystallization, were determined with an electron microprobe. A parallel petrographic study of these samples, and five others in which Keil and Fredriksson found variable olivine compositions, was used to relate the extent of ...
Robert T. Dodd, Randall Van Schmus
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Metal formation in Ordinary Chondrite
2019Ordinary chondrites (OC) are undifferentiated meteorites, mainly composed of silicates, metal and sulfide, which underwent metamorphism due to 26 Al heating. It is commonly proposed that differentiated bodies have been formed by differentiation (i.e. metal silicate segregation) of early formed undifferentiated bodies.
Florin, G. +3 more
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