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Ulf Söderlund

Ulf Söderlund

Professor

Ulf Söderlund

Paleomagnetism and U-Pb age of the 2.4 Ga Erayinia mafic dykes in the south-western Yilgarn, Western Australia: Paleogeographic and geodynamic implications

Author

  • Sergei A. Pisarevsky
  • Bert De Waele
  • Sarah Jones
  • Ulf Söderlund
  • Richard E. Ernst

Summary, in English

We present results from a paleomagnetic study of the previously undated Erayinia dykes intruding the south-western Yilgarn Craton. The U-Pb TIMs baddeleyite age of these dykes is now 2401 +/- 1 Ma, which is about 10 m.y. younger than the 2418-2410 Ma Widgiemooltha dyke swarm. The paleomagnetic study isolated a stable primary remanence with steep downward direction, and the paleomagnetic pole (22.7 degrees S. 150.5 degrees E, A(95) = 11.4 degrees) is similar, but not identical to that of the previously studied Widgiemooltha dykes. We interpret this difference as the result of the movement of the Yilgam Craton toward the pole at similar to 1 degrees/m.y. angular speed, which is comparable with tectonic plates' velocities during the Phanerozoic. Paleomagnetic polarities of Widgiemooltha and Erayinia dykes suggest that at least one geomagnetic reversal occurred between these two magmatic events. The estimated amplitude of geomagnetic secular variations at c. 2400 Ma is slightly higher than predicted by the existing models for the last 5 m.y. at the c. 64 degrees latitude. The paleomagnetic data and patterns of c. 2.6-2.1 Ga mafic dyke swarms permit the recently suggested reconstruction of the Paleoproterozoic supercontinent. (C) 2014 Elsevier B.V. All rights reserved.

Department/s

  • Lithosphere and Biosphere Science

Publishing year

2015

Language

English

Pages

222-231

Publication/Series

Precambrian Research

Volume

259

Document type

Journal article

Publisher

Elsevier

Topic

  • Geology

Keywords

  • Paleomagnetism
  • U-Pb TIMs age
  • Paleoproterozoic
  • Yilgarn Craton
  • Mafic
  • dykes
  • Supercontinent

Status

Published

ISBN/ISSN/Other

  • ISSN: 0301-9268