The geologic history of Patagonia: Its southern connection through time

RAMOS, V.A.; FOLGUERA, A.; GHIGLIONE, M.C.

San Carlos de Bariloche

Congreso; VI Southern Connection Congress; 2010

Patagonia, one of the less populated areas of South America, and a vast semidesert land, was the inspiration for many unusual hypotheses on its geologic origin. However, based on modern plate tectonic concepts the history of Patagonia records a complex interaction with the Gondwana supercontinent and striking connections with the present southern continental masses. Patagonia together with the Antarctic Peninsula and some other minor crustal blocks participated in the amalgamation of Gondwana during the Brasiliano-Panafrican orogeny (~ 530 Ma). Sooner after the amalgamation with Gondwana, subsequent rifting led to the isolation of Patagonia during most of the Paleozoic times. An important collision with the Antarctic Peninsula at about 280 Ma marked the new cycle of amalgamation in the latest Carboniferous times. By the end of the Paleozoic had one of the stronger connections with the Antarctic and other austral land-masses. Subsequent re-amalgamation with Gondwana at 280 Ma, gave the present location to Patagonia. Its southern connection lasted until Middle Jurassic times when near 160 Ma, during the early opening of the Weddell Sea, Antarctica start rifting away. However, final disconnection took place near 30 Ma, when the Drake Passage opened and the circumpolar currents were developed. Collisions along the Pacific side triggered Cordillera uplift and early glaciations at ~ 6 Ma.