Results 161 to 170 of about 535 (200)

Significance of the unequilibrated ordinary chondrites

Journal of Geophysical Research, 1965
Olivine 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
openaire   +1 more source

Physical properties of ordinary chondrites

Journal of Geophysical Research: Solid Earth, 1983
Physical properties (intrinsic and bulk densities, porosity, compressional and shear wave velocities, thermal diffusivity, and conductivity) are measured on 11 ordinary chondrites, one carbonaceous chondrite, and two achondritic clasts of a mesosiderite.
Kiyoshi Yomogida, Takafumi Matsui
openaire   +1 more source

Paleomagnetic systematics of ordinary chondrites

Earth and Planetary Science Letters, 1975
The investigation shows that the decrease in intensity and the increase in stability of natural remanent magnetization (NRM) to alternating field (AF) demagnetization roughly parallel the decrease in Ni-Fe metal content and the corresponding enrichment of the metal phases in Ni.
Aviva Brecher, Rambabu P. Ranganayaki
openaire   +1 more source

Primordial Rare Gases in Unequilibrated Ordinary Chondrites

Science, 1967
The 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

Metallic copper in ordinary chondrites

Meteoritics, 1994
Abstract— 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

Ordinary Chondrites

Ordinary chondrites, the most abundant meteorites, constitute about 80% of meteorite falls and are essential to our understanding of cosmochemistry. They provide important information about planetary accretion, the early Solar System, and the geological history of asteroids, including such processes as thermal metamorphism, shock metamorphism, and ...
openaire   +1 more source

Metamorphism of the ordinary chondrites: A review

Geochimica et Cosmochimica Acta, 1969
Abstract Textural variations among the ordinary chondrites are paralleled by mineralogioal and chemical trends, most of which are consistent with the view that these chondrites have experienced various degrees of alteration in the solid state.
openaire   +1 more source

The matrices of unequilibrated ordinary chondrites: Implications for the origin and history of chondrites

Geochimica et Cosmochimica Acta, 1981
The matrices of 16 unequilibrated chondrites were examined by optical microscopy, an electron microprobe, and a scanning electron microscope. The fine-grained, opaque, silicate matrix of type 3 unequilibrated chondrites was compositionally, mineralogically, and texturally different from the chondrules and their fragments; it may be the low temperature ...
Gary R. Huss, Klaus Keil, G.J. Taylor
openaire   +1 more source

The origin and history of ordinary chondrites: A study by iron isotope measurements of metal grains from ordinary chondrites

Geochimica et Cosmochimica Acta, 2008
Chondrules and chondrites provide unique insights into early solar system origin and history, and iron plays a critical role in defining the properties of these objects. In order to understand the processes that formed chondrules and chondrites, and introduced isotopic fractionation of iron isotopes, we measured stable iron isotope ratios 56Fe/54Fe and
Theis, K. J., Burgess, R.; id_orcid 0000-0001-7674-8718, Lyon, I. C., Sears, D. W.   +3 more
openaire   +2 more sources

CO3 Chondrites: Metamorphic Sequence and Interclassification with Ordinary Chondrites

2005
Metamorphic grade of 7 CO chondrites is determined based on structural order of the Organic Matter. Petrographic types are attempted by interclassification with ordinary chondrites and are confronted with petrographic tracers.
Bonal, Lydie, Bourot-Denise, M., Boronkay, A., Montagnac, Gilles, Quirico, Eric   +4 more
openaire   +1 more source