Magnetic Evidence for a Partially Differentiated Carbonaceous Chondrite Parent Body
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Weiss-2011-Apr-Magnetic Evidence for a Partially Differentiated Carbonaceous Chondrite Parent Body.pdf
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Author(s)
Shuster, David L.
Ebel, Denton S.
Gattacceca, Jerome
Carporzen, Laurent
Weiss, Benjamin P.
Elkins Tanton, Linda T.
Date Issued
April 2011
Journal
Proceedings of the National Academy of Sciences of the United States of America
Publisher
National Academy of Sciences
Citation
Carporzen, L. et al. “From the Cover: Magnetic evidence for a partially differentiated carbonaceous chondrite parent body.” Proceedings of the National Academy of Sciences 108 (2011): 6386-6389. Web. 9 Nov. 2011. © 2011 National Academy of Sciences
Version
Final published version
Abstract
The textures of chondritic meteorites demonstrate that they are not the products of planetary melting processes. This has long been interpreted as evidence that chondrite parent bodies never experienced large-scale melting. As a result, the paleomagnetism of the CV carbonaceous chondrite Allende, most of which was acquired after accretion of the parent body, has been a long-standing mystery. The possibility of a core dynamo like that known for achondrite parent bodies has been discounted because chondrite parent bodies are assumed to be undifferentiated. Resolution of this conundrum requires a determination of the age and timescale over which Allende acquired its magnetization. Here, we report that Allende’s magnetization was acquired over several million years (Ma) during metasomatism on the parent planetesimal in a > ∼ 20 μT field up to approximately 9—10 Ma after solar system formation. This field was present too recently and directionally stable for too long to have been generated by the protoplanetary disk or young Sun. The field intensity is in the range expected for planetesimal core dynamos, suggesting that CV chondrites are derived from the outer, unmelted layer of a partially differentiated body with a convecting metallic core.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.1073/pnas.1017165108
