A nonmagnetic differentiated early planetary body

Benjamin P. Weiss, Huapei Wang, Thomas Sharp, Jérôme Gattacceca, David L. Shuster, Brynna Downey, Jinping Hu, Roger R. Fu, Aaron T. Kuan, Clément Suavet, Anthony J. Irving, Jun Wang, Jiajun Wang

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Paleomagnetic studies of meteorites have shown that the solar nebula was likely magnetized and that many early planetary bodies generated dynamo magnetic fields in their advecting metallic cores. The surface fields on these bodies were recorded by a diversity of chondrites and achondrites, ranging in intensity from several μT to several hundred μT. In fact, an achondrite parent body without evidence for paleomagnetic fields has yet to be confidently identified, hinting that early solar system field generation and the dynamo process in particular may have been common. Here we present paleomagnetic measurements of the ungrouped achondrite NWA 7325 indicating that it last cooled in a near-zero field (<∼1.7 μT), estimated to have occurred at 4563.09±0.26 million years ago (Ma) from Al–Mg chronometry. Because NWA 7325 is highly depleted in siderophile elements, its parent body nevertheless underwent large-scale metal-silicate differentiation and likely formed a metallic core. This makes NWA 7325 the first recognized example of an essentially unmagnetized igneous rock from a differentiated early solar system body. These results indicate that all magnetic fields, including those from any core dynamo on the NWA 7325 parent body, the solar nebula, young Sun, and solar wind, were <1.7 μT at the location of NWA 7325 at 4563 Ma. This supports a recent conclusion that the solar nebula had dissipated by ∼4 million years after solar system formation. NWA 7325 also serves as an experimental control that gives greater confidence in the positive identification of remanent magnetization in other achondrites.

Original languageEnglish (US)
Pages (from-to)119-132
Number of pages14
JournalEarth and Planetary Science Letters
Volume468
DOIs
StatePublished - Jun 15 2017

Fingerprint

achondrite
Solar system
achondrites
parent body
solar system
solar nebula
Igneous rocks
Magnetic fields
Meteorites
Silicates
Solar wind
magnetic field
siderophile element
Sun
Magnetization
remanent magnetization
Metals
siderophile elements
chondrite
meteorite

Keywords

  • differentiation
  • dynamo
  • meteorites
  • paleomagnetism
  • planetesimals

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Weiss, B. P., Wang, H., Sharp, T., Gattacceca, J., Shuster, D. L., Downey, B., ... Wang, J. (2017). A nonmagnetic differentiated early planetary body. Earth and Planetary Science Letters, 468, 119-132. https://doi.org/10.1016/j.epsl.2017.03.026

A nonmagnetic differentiated early planetary body. / Weiss, Benjamin P.; Wang, Huapei; Sharp, Thomas; Gattacceca, Jérôme; Shuster, David L.; Downey, Brynna; Hu, Jinping; Fu, Roger R.; Kuan, Aaron T.; Suavet, Clément; Irving, Anthony J.; Wang, Jun; Wang, Jiajun.

In: Earth and Planetary Science Letters, Vol. 468, 15.06.2017, p. 119-132.

Research output: Contribution to journalArticle

Weiss, BP, Wang, H, Sharp, T, Gattacceca, J, Shuster, DL, Downey, B, Hu, J, Fu, RR, Kuan, AT, Suavet, C, Irving, AJ, Wang, J & Wang, J 2017, 'A nonmagnetic differentiated early planetary body', Earth and Planetary Science Letters, vol. 468, pp. 119-132. https://doi.org/10.1016/j.epsl.2017.03.026
Weiss, Benjamin P. ; Wang, Huapei ; Sharp, Thomas ; Gattacceca, Jérôme ; Shuster, David L. ; Downey, Brynna ; Hu, Jinping ; Fu, Roger R. ; Kuan, Aaron T. ; Suavet, Clément ; Irving, Anthony J. ; Wang, Jun ; Wang, Jiajun. / A nonmagnetic differentiated early planetary body. In: Earth and Planetary Science Letters. 2017 ; Vol. 468. pp. 119-132.
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