Publication
Names
  • H. Y. McSween
Title
Petrographic variations among carbonaceous chondrites of the Vigarano type
Abstract
The Vigarano subtype is a petrographically complex class of meteorites. Oxidized and reduced groups can be distinguished on the basis of metal vs magnetite abundances and Ni contents of sulfide minerals. These meteorites also differ in the proportions of matrix and chondrules and in polymict character. Slight bulk chemical differences correlate with the recognized petrologic groupings. It is likely that the Vigarano subtype includes several previously unrecognized subgroups. Metamorphism has affected Coolidge, Mulga (West) and, to a lesser extent, Allende, as evidenced by ferromagnesian mineral equilibration, Fe-enrichment of fine-grained inclusions, and loss of some volatile gases. Because of the metamorphic effects in the Allende chondrite (the only meteorite of the group that has been intensively studied) and the petrographic differences among all meteorites of the Vigarano subtype, it is suggested that Allende alone may not adequately reflect the wide spectrum of properties in this important class of meteorites.
Keywords
carbonaceous chondrites, CV chondrites, meteorite Allende, meteorite Axtell, meteorite Bali, meteorite Mokoia, meteorite Grosnaja, meteorite Efremovka, meteorite Vigarano, meteorite Leoville, meteorite Kaba, meteorite Al Rais, meteorite Coolidge, meteorite Arch, meteorite Mulga, chemical analyses, petrographic analyses
Content
material-matter, planetary sciences
Year
1977
Journal
Geochimica et Cosmochimica Acta
Volume
41
Pages
1777 - 1790
Pages number
14
Document type
article
Publication state
published