Magnetic evidence for a partially differentiated carbonaceous chondrite parent body

Laurent Carporzen, Benjamin P. Weiss, Linda T. Elkins-Tanton, David L. Shuster, Denton Ebel, Jérôme Gattacceca

Research output: Contribution to journalArticle

65 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)6386-6389
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number16
DOIs
StatePublished - Apr 19 2011

Keywords

  • Differentiation
  • Early solar system
  • Magnetic field
  • Paleointensity
  • Planetesimal

ASJC Scopus subject areas

  • General

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