When did the deformation along the South Western Gondwana margin begin?

TOMEZZOLI, R.N.

Buzios

Congreso; Gondwana meeting; 2011

SESSION 2 – GONDWANIDES Conveners: I. Dalziel (USA), Renata Nela Tomezzoli (Argentina) and  Maarten de Wit (South Africa) ian@utig.ig.utexas.edu, renata@gl.fcen.uba.ar, Maarten.DeWit@uct.ac.za The Gondwanide Orogeny: In his classic 1937 book "Our Wandering Continents", the South African geologist Alex Du Toit mapped his "Samfrau Geosyncline" from the Sierra de La Ventana of Argentina into the Cape Mountains of South Africa and through a then unknown part of Antarctica to eastern Australia. He thereby used widely separated parts of what we now call the Gondwanide orogen as piercing points in reconstructing Gondwanaland and arguing for the hypothesis of continental drift. With the aid of marine and satellite geophysics, detailed geologic studies and paleomagnetism, we can now accurately trace the Gondwanides from South America and Africa through the restored Lafonian and Ellsworth-Whitmore microplates to the Pensacola Mountains along the Transantarctic Mountains front. There are, however, several outstanding questions concerning the orogen, the nature and the cause of the Gondwanide orogeny. Does the orogen really extend to eastern Australia? Did all the deformation of the Cambrian to Permian succession occur after the deposition of Glossopteris-bearing Permian strata, or was there an earlier phase? What was the cause of the deformation in an orogen far inboard of the Pacific margin of Gondwanaland, at least in South American, Africa and Antarctica? The session is planned to bring together workers in every sector of this important and enigmatic, and now far flung orogen. A Gondwana meeting on the Atlantic coast of South America seems an ideal place to convene such a session.