title: Evidence for a dynamo in the main group pallasite parent body.
abstract: Understanding the origin of pallasites, stony-iron meteorites made mainly of olivine crystals and FeNi metal, has been a vexing problem since their discovery. Here, we show that pallasite olivines host minute magnetic inclusions that have favorable magnetic recording properties. Our paleointensity measurements indicate strong paleomagnetic fields, suggesting dynamo action in the pallasite parent body. We use these data and thermal modeling to suggest that some pallasites formed when liquid FeNi from the core of an impactor was injected as dikes into the shallow mantle of a ~200-kilometer-radius protoplanet. The protoplanet remained intact for at least several tens of millions of years after the olivine-metal mixing event.
authors.affiliation: Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14627, USA. john.tarduno@rochester.edu
authors.forename: John A
authors.initials: JA
authors.lastname: Tarduno
authors.forename: Rory D
authors.initials: RD
authors.lastname: Cottrell
authors.forename: Francis
authors.initials: F
authors.lastname: Nimmo
authors.forename: Julianna
authors.initials: J
authors.lastname: Hopkins
authors.forename: Julia
authors.initials: J
authors.lastname: Voronov
authors.forename: Austen
authors.initials: A
authors.lastname: Erickson
authors.forename: Eric
authors.initials: E
authors.lastname: Blackman
authors.forename: Edward R D
authors.initials: ER
authors.lastname: Scott
authors.forename: Robert
authors.initials: R
authors.lastname: McKinley