Results 201 to 210 of about 11,238 (241)

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
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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
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The Sharps Chondrite - New Evidence on the Origin of Chondrules and Chondrites

1969
Chemical, petrographic and mineralogical studies of the Sharps chondrite reveal that this meteorite is a complex agglomerate of chondrules and lithic fragments in a matrix similar in composition to carbonaceous chondrites. One type of fragment resembles Type II carbonaceous chondrites in composition, but contains igneous glass and has been depleted in ...
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The carbonaceous chondrites

Space Science Reviews, 1963
The carbonaceous chondrites are a group of stony meteorites characterized by the presence of an appreciable amount of carbonaceous material other than free carbon (diamond and graphite). They have been divided into three subgroups known respectively as Type I, Type II, and Type III.
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The Trebbin chondrite

Meteoritics, 1990
Abstract— The Trebbin chondrite (fall, 1988) is a shocked, cataclastic breccia of LL6 parentage.
G. Andrehs, K. Adam
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Metamorphism in chondrites

Geochimica et Cosmochimica Acta, 1962
Abstract The concept of chondrites as metamorphic rocks is examined. Mineralogies of four chondrites whose textures indicate different degrees of thermal recrystallization are presented. It appears that relatively unmetamorphosed or “primary” chondritic material consisted of reduced chondrules (metallic iron, magnesian silicates) in an oxidized ...
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The enstatite chondrites

Geochimica et Cosmochimica Acta, 1966
Abstract Fifteen enstatite chondrites have been recognized: Abee, Adhi Kot, Atlanta, Bethune, Blithfield, Daniel's Kuil, Hvittis, Indarch, Jajh deh Kot Lalu, Khairpur, Kota-Kota, Pillistfer, St. Mark's, Saint-Sauveur and Ufana. Their essential minerals are enstatite and/or clinoenstatite (40–60%), kamacite (20–28%), troilite (7–15%), and sometimes ...
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The relationship between CM and CO chondrites: Insights from combined analyses of titanium, chromium, and oxygen isotopes in CM, CO, and ungrouped chondrites

Geochimica Et Cosmochimica Acta, 2021
Devin L Schrader, Meenakshi Wadhwa, Jemma Davidson   +2 more
exaly  

Age and genetic relationships among CB, CH and CR chondrites

Geochimica Et Cosmochimica Acta, 2023
Gerrit Budde, Thorsten Kleine, Elias Wolfer   +2 more
exaly  

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 ...
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