40Ar/39Ar dating of 1.0-1.1 Ga magnetizations from the São Francisco and Kalahari cratons: tectonic implications for Pan-African and Brasiliano mobile belts

Paul R. Renne, Tullis C. Onstott, Manoel S. D'Agrella-Filho, Igor G. Pacca, Wilson Teixeira

Research output: Contribution to journalArticle

92 Scopus citations

Abstract

Paleomagnetic poles from 1.1-1.0 Ga dyke swarms in eastern Brazil (São Francisco Craton) are compared with 1.0 Ga poles from granulites of the Namaqua Province in southern Africa (Kalahari Graton). The intrusive ages of dykes are estimated from 40Ar/39Ar dating of outgassed biotites from baked country rocks. The age of magnetization for the granulites is derived by combining 40Ar/39Ar hornblende and biotite dates. When restored to a Mesozoic pre-drift configuration the paleomagnetic poles are in crude spatial agreement but are temporally discordant. To satisfy both paleomagnetic and geochronologic constraints, a reconstruction involving separation of the São Francisco and Kalahari cratons is required, indicating that the intervening Pan-African (Brasiliano) mobile belt may record a craton-craton collision.

Original languageEnglish (US)
Pages (from-to)349-366
Number of pages18
JournalEarth and Planetary Science Letters
Volume101
Issue number2-4
DOIs
StatePublished - Dec 1990

All Science Journal Classification (ASJC) codes

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

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