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Palaeomagnetism and Palaeoclimates |
Lamont-Doherty Geological Observatory and Department of Geological Sciences, Columbia University, Palisades, NY 10964, USA
Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109, USA
Revised palaeogeographic reconstructions of the Atlantic-bordering continents and intervening terranes are presented for the Siluro-Devonian boundary, Early Devonian, and Late Devonian, based on incorporation of new palaeomagnetic results that have become available from Laurentia and Gondwana. The key features of the palaeogeographic model are the transpressive collision between the eastern margin of Laurentia and the northwest South American margin of Gondwana in the Siluro-Devonian, and the subsequent Devonian retreat of the north African margin and the development of a wide ocean between Africa and Europe by the Late Devonian. Although rather complex and involving rapid motions especially of Gondwana, the revised Devonian plate tectonic evolution as indicated by palaeomagnetism is not inconsistent with biogeographic and palaeoclimatological evidence.