Fission Track Cooling Ages in the Brazilian Central Plateau Linked to Orogenies and Continental Break-Up

Abstract

AbstractFission-track analysis in zircon and apatite detrital grains from Mesoproterozoic sedimentary sequences show evidence of two main cooling episodes in central Brazil and indicate the possibility of four distinct events. Apatite fission track reveals a main cooling episode during the Late Cretaceous (at ca. 64 Ma), providing important clues on cooling by uplift and denudation during drifting of South America and Africa. The event can be directly correlated to the intraplate tectonic deformation due to flexural subsidence at the Atlantic margin and Andes orogeny and development of intracratonic basins. Zircon fission track data indicate a main cooling event at 375 Ma interpreted as related to the Famatinian orogeny. Zircon data also suggest three distinct cooling events: (i) a Neoproterozoic-Cambrian event, probably related to the thermal decay of West Gondwana assembly, (ii) a Devonian-Carboniferous event, probably related to the late Famatinian orogeny, and (iii) an early Permian to Triassic event, linked to the late Gondwanide orogeny. These results indicate that the processes of assembly and break-up of supercontinents, might significantly affect the plate interior, especially along ancient orogenic belts.KeywordsZircon fission-trackApatite fission-trackThermochronology