Results 151 to 160 of about 1,510 (199)
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Amino acids in carbonaceous chondrites
Origins of Life, 1974For 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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Geochimica et Cosmochimica Acta, 1956
Abstract Chondrites have uniform gallium contents; the average of nineteen samples is 5.3 p.p.m. Ga, with the range 4.2–6.8 p.p.m. Composites of these contain an average of 3.2 p.p.m. Ga in the silicate phase, 15 p.p.m. in the metal phase, and 12 p.p.m. in the sulphide phase.
Hiroshi Onishi, E.B Sandell
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Abstract Chondrites have uniform gallium contents; the average of nineteen samples is 5.3 p.p.m. Ga, with the range 4.2–6.8 p.p.m. Composites of these contain an average of 3.2 p.p.m. Ga in the silicate phase, 15 p.p.m. in the metal phase, and 12 p.p.m. in the sulphide phase.
Hiroshi Onishi, E.B Sandell
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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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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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Abstract Although enstatite chondrites constitute only 1.5% of well-documented meteorite falls, they are distinctive in being the most highly reduced chondrites. The two main enstatite-chondrite groups—EH (high bulk iron, high siderophiles) and EL (low bulk iron, low siderophiles)—differ in bulk oxidation state and in their abundance ...
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Age and genetic relationships among CB, CH and CR chondrites
Geochimica Et Cosmochimica Acta, 2023Elias Wolfer +2 more
exaly
The Loongana (CL) group of carbonaceous chondrites
Geochimica Et Cosmochimica Acta, 2021Knut Metzler +2 more
exaly
The mineralogy and alteration history of the Yamato-type (CY) carbonaceous chondrites
Geochimica Et Cosmochimica Acta, 2023Martin D Suttle +2 more
exaly