Results 151 to 160 of about 6,388 (192)
Some of the next articles are maybe not open access.
Primordial Rare Gases in Unequilibrated Ordinary Chondrites
Science, 1967The primordial gases of eight unequilibrated ordinary chondrites are strongly fractionated with respect to "cosmic" proportions. The absolute amounts are roughly proportional to the degree of disequilibration. Apparently, ordinary chondrites originally contained considerably larger amounts of primordial rare gases.
D, Heymann, E, Mazor
openaire +2 more sources
Presolar components in the ordinary chondrites
Earth and Planetary Science Letters, 1990Abstract As part of the search for presolar material in primitive meteorites eleven ordinary chondrites, ranging from petrologic type 3 to 6, have been analysed for C and N isotopes by stepped combustion. Isotopically anomalous components have been found only in those meteorites of petrologic type 3.6 or below.
C.M.O'D. Alexander +3 more
openaire +1 more source
Moderately volatile siderophiles in ordinary chondrites
Earth and Planetary Science Letters, 1979Abstract The contents of the moderately volatile elements Ga, Ge, Cu and Sb in ordinary chondrites give us some clues with regard to the metal-silicate fractionation process. Their concentration in coexisting magnetic and non-magnetic portions of members of each ordinary chondrite group will be discussed. Germanium and Sb are mostly siderophilic, but
Ermanno R. Rambaldi, Miguel Cendales
openaire +1 more source
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
openaire +1 more source
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
openaire +1 more source
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 ...
openaire +1 more source
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.
openaire +1 more source
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
openaire +1 more source
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.
openaire +1 more source
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
openaire +1 more source