Palaeogeographic and geodynamic evolution of the Gondwana continental margins during the Cambrian |
| |
Authors: | Pierre Courjault-Radé Françoise Debrenne Anna Gandin |
| |
Affiliation: | Laboratoire de Minéralogie (URA 067, CNRS), 39, Allées 1. Guesde, F-31062 Toulovse Cedex, France;lnstitut de Paléontologie (URA 012, CNRS), 8, rue Buffon, F-7500 Paris, France;Diprtimento di Scienze della Terra, Via delle Cerchia, 3, 1–53100 Siena, italy |
| |
Abstract: | During the Cambrian, two types of continental margins occurred around Gondwana. The eastern margin (Antarctica, Australia and southern South America) was characterized by a narrow continental shelf with a steep slope separating the shallow water environment from a deep-oceanic one accompanied by mafidultramafic volcanics. The western margin was characterized by a wider continental shelf, probably passing gradually to an unknown outer basin. This comprised three main domains: the Asiatic shelf, composed of distinct cratonic blocks, presumably separated from each other by deeper-water/ volcanic intracontinental basins; the European shelf, characterized by the development of shallow intracontinental siliciclastic basins; and the Americanc-African shelf, morphologically and depositionally uniform. The distinction of these two Gondwana continental margins expresses their different geodynamic behaviour during Cambrian extensional tectonics. In fact, the sedimentary/palaeogeographic evolution, suggests the establishment of an active Pacific-like margin in the eastern domain, and the tentative establishment of a divergent Atlantic-like margin, in the westem one. |
| |
Keywords: | |
|
|