Reativações intraplaca no graben do Rio dos Bagres, Serra da Mantiqueira Setentrional: análise integrada de morfotectônica, termocronologia (U-Th-Sm)/He e isótopos cosmogênicos

Abstract

The application of low-temperature thermochronology and cosmogenic isotope produced in situ along with morphotectonic analyses showed a landscape evolution model between Permian and Quaternary. Also, allow provided the speed of superficial process in the response of tectonic and denudational forces that created and shaped the Mantiqueira range and the Bagres river half-graben. It will provide new thermochronological data by (U-Th-Sm)/He and 10Be cosmogenic isotope in situ produce. The (U-Th-Sm)/He results indicates a complex thermal history with low crustal cooling rates (1.8 m/My), following by two fast cooling phases at Lower Jurassic (30 m/My) and Upper Cretaceous (18 m/My) and a crustal heating at 75 My ago. The denudation rates derivated by cosmogenic isotope indicated low rates at Quaternary between 5 28 m/My-1. The morphotectonic analyses revealed the presence of a hierarchy at geomorphological domains. NE-SW Neoproterozoic structurals formed steepen compartments in that direction and then cross-cut by NW-SE Mesozoic structurals generating smaller compartments. The result of integrated analyses those three tools allow confirming that the actual landscape framework was the result of activation and tectonic reactivations still in force and it doesn t produce denudation rate higher than 30 m/My since Lower Jurassic