Results 201 to 210 of about 43,521 (279)

Quantitative models for the elemental and isotopic fractionations in chondrites: The carbonaceous chondrites

Geochimica et Cosmochimica Acta, 2019
A quantitative understanding of the elemental and isotopic fractionations recorded in the compositions of the chondritic meteorites would provide fundamental constraints for astrophysical models of early Solar System evolution.
C. Alexander
semanticscholar   +1 more source

Calcium isotopic compositions of chondrites

Geochimica Et Cosmochimica Acta, 2017
Shichun Huang
exaly   +2 more sources

The Bencubbin chondrite breccia and its relationship to CR chondrites and the ALH85085 chondrite

Meteoritics, 1990
Abstract— Bencubbin is an unclassified meteorite breccia which consists mainly of host silicate (∼40 vol.%) and host metal (∼60%) components. Rare (< 1%) ordinary chondrite clasts and a dark xenolith (formerly called a carbonaceous chondrite clast) are also found.
Michael K. Weisberg, Martin Prinz, Cherukupalli E. Nehru   +2 more
openaire   +1 more source

Brecciation among 2280 ordinary chondrites – Constraints on the evolution of their parent bodies

Geochimica et Cosmochimica Acta, 2018
After accretion of meteorite parent bodies, larger and smaller collisions have led to significant modifications of these bodies. Involved processes include excavation of material, thermal metamorphism, melting, mixing of different materials, re-accretion,
A. Bischoff, M. Schleiting, R. Wieler, M. Patzek   +3 more
semanticscholar   +1 more source

Oxygen isotopes in R-chondrite magnetite and olivine: links between R chondrites and ordinary chondrites

Geochimica et Cosmochimica Acta, 2000
Ion-microprobe studies yield Δ17O (=δ17O − 0.52 · δ18O) values in magnetite from the Rumurti chondrite (RC) PCA91241 (which is paired with PCA91002) of +3.1 to +3.9‰, slightly higher than that in O from whole-rock R samples. Despite Δ17O values in whole-rock RCs that are much (by ca.
James P Greenwood, Alan E Rubin, John T Wasson   +2 more
openaire   +1 more source

Feldspar in Chondrites

Science, 1965
Whereas most chondrites contain sodic plagioclase (or occasionally maskelynite, its glassy equivalent), a few are free of feldspar. Absence of plagioclase is correlated with the presence of calcium-poor clinopyroxene (pigeonite sensu lato ) instead of orthopyroxene.
openaire   +2 more sources

What is controlling the reflectance spectra (0.35–150 µm) of hydrated (and dehydrated) carbonaceous chondrites?

Icarus (New York, N.Y. 1962), 2018
In order to determine the controls on the reflectance spectra of hydrated carbonaceous chondrites, reflectance spectra were measured for a series of samples with well-determined mineralogy, water-content, and thermal history.
P. Beck, A. Maturilli, A. Garenne, P. Vernazza, J. Helbert, E. Quirico, B. Schmitt   +6 more
semanticscholar   +1 more source

Chainpur-like Chondrites: Primitive Precursors of Ordinary Chondrites?

Science, 1966
Chainpur and similar, apparently primitive, chondritic meteorites may be precursors of ordinary chondrites; a variety of evidence supports this working hypothesis. In general, carbonaceous chondrites seem to be related collaterally to this genetic sequence rather than being direct ancestors of ordinary chondrites.
R A, Schmitt, R H, Smith, G G, Goles
openaire   +2 more sources

Amino acids in carbonaceous chondrites

Origins of Life, 1974
For almost 20 years laboratory experiments have advanced the concepts of chemical evolution, particularly with regard to formation of the amino acids. What has been generally lacking is concrete natural evidence for this chemical evolution hypothesis.
J G, Lawless, E, Peterson
openaire   +2 more sources

The compositional classification of chondrites: III. Ungrouped carbonaceous chondrites

Geochimica et Cosmochimica Acta, 1982
Abstract Seven carbonaceous chondrites (Allan Hills A77307, Adelaide, Al Rais, Coolidge, Grosnaja, Karoonda and Renazzo) with uncertain classifications were analyzed by instrumental and radiochemical neutron activation analysis for 29 elements: Na, Mg, Al, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Zn, Ga, Ge, As, Se, Br, Ru, Cd, Sb, La, Sm, Eu, Yb, Lu, Os ...
Gregory W. Kallemeyn, John T. Wasson
openaire   +1 more source