Primary igneous carbon in ureilites - Petrological implications
The ureilite meteorites are carbonaceous olivine-pyroxene achondrites. They typically contain up to 4 wt.% carbon (carbonaceous matrix) as graphite, diamond, and lonsdaleite. Shock degradation has effectively obliterated primary textures in the carbonaceous matrix of previously described ureilites,...
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ftnasantrs:oai:casi.ntrs.nasa.gov:19830034142 2023-05-15T13:35:32+02:00 Primary igneous carbon in ureilites - Petrological implications Berkely, J. L. Jones, J. H. Unclassified, Unlimited, Publicly available JAN 1, 1982 http://ntrs.nasa.gov/search.jsp?R=19830034142 unknown http://ntrs.nasa.gov/search.jsp?R=19830034142 Accession ID: 83A15360 Copyright Other Sources 91 Lunar and Planetary Science Conference; March 15-19, 1982; Houston, TX 1982 ftnasantrs 2012-02-15T15:24:39Z The ureilite meteorites are carbonaceous olivine-pyroxene achondrites. They typically contain up to 4 wt.% carbon (carbonaceous matrix) as graphite, diamond, and lonsdaleite. Shock degradation has effectively obliterated primary textures in the carbonaceous matrix of previously described ureilites, a factor that has hampered efforts to explain the origin of this material. In contrast, the Antarctic ureilite ALHA78019 displays perfectly preserved primary textures in the carbonaceous matrix characterized by euhedral graphite blades intergrown with Fe-Ni metal and sulfide (diamonds are absent). This petrographic feature suggests that most graphite in ureilites originated by crystallization from a C-rich metallic phase. Assuming that fO2 is controlled by C-CO-CO2 reactions, the compositions of silicates and metals in ureilites imply a two-stage redox history. The noble gases and rare earths of ureilites are discussed in light of this model. Other/Unknown Material Antarc* Antarctic NASA Technical Reports Server (NTRS) Antarctic The Antarctic |
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NASA Technical Reports Server (NTRS) |
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91 |
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91 Berkely, J. L. Jones, J. H. Primary igneous carbon in ureilites - Petrological implications |
topic_facet |
91 |
description |
The ureilite meteorites are carbonaceous olivine-pyroxene achondrites. They typically contain up to 4 wt.% carbon (carbonaceous matrix) as graphite, diamond, and lonsdaleite. Shock degradation has effectively obliterated primary textures in the carbonaceous matrix of previously described ureilites, a factor that has hampered efforts to explain the origin of this material. In contrast, the Antarctic ureilite ALHA78019 displays perfectly preserved primary textures in the carbonaceous matrix characterized by euhedral graphite blades intergrown with Fe-Ni metal and sulfide (diamonds are absent). This petrographic feature suggests that most graphite in ureilites originated by crystallization from a C-rich metallic phase. Assuming that fO2 is controlled by C-CO-CO2 reactions, the compositions of silicates and metals in ureilites imply a two-stage redox history. The noble gases and rare earths of ureilites are discussed in light of this model. |
format |
Other/Unknown Material |
author |
Berkely, J. L. Jones, J. H. |
author_facet |
Berkely, J. L. Jones, J. H. |
author_sort |
Berkely, J. L. |
title |
Primary igneous carbon in ureilites - Petrological implications |
title_short |
Primary igneous carbon in ureilites - Petrological implications |
title_full |
Primary igneous carbon in ureilites - Petrological implications |
title_fullStr |
Primary igneous carbon in ureilites - Petrological implications |
title_full_unstemmed |
Primary igneous carbon in ureilites - Petrological implications |
title_sort |
primary igneous carbon in ureilites - petrological implications |
publishDate |
1982 |
url |
http://ntrs.nasa.gov/search.jsp?R=19830034142 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Other Sources |
op_relation |
http://ntrs.nasa.gov/search.jsp?R=19830034142 Accession ID: 83A15360 |
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Copyright |
_version_ |
1766066867505463296 |