Devonian to Permian post-orogenic denudation of the Brasília Belt of West Gondwana: insights from apatite fission track thermochronology

The Brasília Belt in southern Brazil is a Neoproterozoic orogenic belt that represents the northern border of the Paraná Basin, a long-lived early Paleozoic intracratonic basin. The belt is surrounded by cratonic domains and were modestly affected and reactivated by the opening of the South Atlantic Ocean during the Cretaceous. Here we present new apatite fission track data from crystalline rocks of the Brasília Belt. The apatite fission track central ages range from 386 to 243 Ma and the mean track lengths range between 13.4 and 14.5 μm. Thermal history modeling reveals Devonian to Permian cooling, which we interpret as the main final exhumation of the Brasília Belt, implying that indeed the influence of posterior Mesozoic and Cenozoic geodynamic history on the belt was limited. The Paraná Basin and surrounding elevated terranes therefore provide a time window to study the tectonic history of Gondwana and the effect of far-field intraplate stresses on the interior of West Gondwana. Rapid basement exhumation of the Brasília Belt is coeval with extension and tectonic subsidence in the Paraná Basin as a result of continent-scale tectonic forces occurring over entire West Gondwana.