H/L Chondrite Lapaz Icefield 031047 - A Feather Of Icarus?
Antarctic meteorite LAP 031047 is an ordinary chondrite composed of loosely consolidated chondritic fragments. Its petrography, oxygen isotopic composition and geochemical inventory are ambiguous and indicate an intermediate character between H and L chondrites. Petrographic indicators suggest LAP 0...
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ftunicentralflor:oai:stars.library.ucf.edu:scopus2010-3978 2023-05-15T13:56:24+02:00 H/L Chondrite Lapaz Icefield 031047 - A Feather Of Icarus? Wittmann, Axel Friedrich, Jon M. Troiano, Julianne Macke, Robert J. Britt, Daniel T. 2011-10-15T07:00:00Z https://stars.library.ucf.edu/scopus2010/2979 unknown STARS https://stars.library.ucf.edu/scopus2010/2979 Scopus Export 2010-2014 text 2011 ftunicentralflor 2022-08-08T17:37:23Z Antarctic meteorite LAP 031047 is an ordinary chondrite composed of loosely consolidated chondritic fragments. Its petrography, oxygen isotopic composition and geochemical inventory are ambiguous and indicate an intermediate character between H and L chondrites. Petrographic indicators suggest LAP 031047 suffered a shock metamorphic overprint below ∼10 GPa, which did not destroy its unusually high porosity of ∼27 vol%. Metallographic textures in LAP 031047 indicate heating above ∼700. °C and subsequent cooling, which caused massive transformation of taenite to kamacite. The depletion of thermally labile trace elements, the crystallization of chondritic glass to microcrystalline plagioclase of unusual composition, and the occurrence of coarsely crystallized chondrule fragments is further evidence for post-metamorphic heating to ∼700-750. °C. However, this heating event had a transient character because olivine and low-Ca pyroxene did not equilibrate. Nearly complete degassing up to very high temperatures is indicated by the thorough resetting of LAP 031047's Ar-Ar reservoir ∼100 ± 55 Ma ago. A noble gas cosmic-ray exposure age indicates it was reduced to a meter-size fragment at <0.5. Ma. In light of the fact that shock heating cannot account for the thermal history of LAP 031047 in its entirety, we test the hypothesis that this meteorite belonged to the near-surface of an Aten or Apollo asteroid that underwent heating during orbital passages close to the Sun. © 2011 Elsevier Ltd. Text Antarc* Antarctic University of Central Florida (UCF): STARS (Showcase of Text, Archives, Research & Scholarship) Antarctic |
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University of Central Florida (UCF): STARS (Showcase of Text, Archives, Research & Scholarship) |
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Antarctic meteorite LAP 031047 is an ordinary chondrite composed of loosely consolidated chondritic fragments. Its petrography, oxygen isotopic composition and geochemical inventory are ambiguous and indicate an intermediate character between H and L chondrites. Petrographic indicators suggest LAP 031047 suffered a shock metamorphic overprint below ∼10 GPa, which did not destroy its unusually high porosity of ∼27 vol%. Metallographic textures in LAP 031047 indicate heating above ∼700. °C and subsequent cooling, which caused massive transformation of taenite to kamacite. The depletion of thermally labile trace elements, the crystallization of chondritic glass to microcrystalline plagioclase of unusual composition, and the occurrence of coarsely crystallized chondrule fragments is further evidence for post-metamorphic heating to ∼700-750. °C. However, this heating event had a transient character because olivine and low-Ca pyroxene did not equilibrate. Nearly complete degassing up to very high temperatures is indicated by the thorough resetting of LAP 031047's Ar-Ar reservoir ∼100 ± 55 Ma ago. A noble gas cosmic-ray exposure age indicates it was reduced to a meter-size fragment at <0.5. Ma. In light of the fact that shock heating cannot account for the thermal history of LAP 031047 in its entirety, we test the hypothesis that this meteorite belonged to the near-surface of an Aten or Apollo asteroid that underwent heating during orbital passages close to the Sun. © 2011 Elsevier Ltd. |
format |
Text |
author |
Wittmann, Axel Friedrich, Jon M. Troiano, Julianne Macke, Robert J. Britt, Daniel T. |
spellingShingle |
Wittmann, Axel Friedrich, Jon M. Troiano, Julianne Macke, Robert J. Britt, Daniel T. H/L Chondrite Lapaz Icefield 031047 - A Feather Of Icarus? |
author_facet |
Wittmann, Axel Friedrich, Jon M. Troiano, Julianne Macke, Robert J. Britt, Daniel T. |
author_sort |
Wittmann, Axel |
title |
H/L Chondrite Lapaz Icefield 031047 - A Feather Of Icarus? |
title_short |
H/L Chondrite Lapaz Icefield 031047 - A Feather Of Icarus? |
title_full |
H/L Chondrite Lapaz Icefield 031047 - A Feather Of Icarus? |
title_fullStr |
H/L Chondrite Lapaz Icefield 031047 - A Feather Of Icarus? |
title_full_unstemmed |
H/L Chondrite Lapaz Icefield 031047 - A Feather Of Icarus? |
title_sort |
h/l chondrite lapaz icefield 031047 - a feather of icarus? |
publisher |
STARS |
publishDate |
2011 |
url |
https://stars.library.ucf.edu/scopus2010/2979 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Scopus Export 2010-2014 |
op_relation |
https://stars.library.ucf.edu/scopus2010/2979 |
_version_ |
1766263905713127424 |