OROGENIC SHORTENING AND PALEOGEOGRAPHY OF THE MAGALLANES BASIN (50° - 56° S.LAT)

The palinspastic restoration of the Patagonian Andes orocline indicates that a shortening of 600 km at the southern extreme is compatible with the available geologic data and the paleomagnetic arc rotation of nearly 90°. A regional balanced cross section was restored in four stages that represent the main events of compressive deformation. The mid-Cretaceous event produced a shortening of 430 km associated to a high grade regional metamorphism in Cordillera Darwin and a period of fast subsidence in the Magallanes foreland basin during the Late Cretaceous. The Late Cretaceous - Cenozoic events produced a total shortening of 170 km, of wich 40 km correspond to the Late Cretaceous, 50 km to the Paleogene and 80 km to the Neogene events. Based on a regional palinspastic restoration, a set of six paleogeographic maps showing the Mesozoic – Cenozoic evolution of the Magallanes basin is presented.