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Denudation history of the summit surfaces of Southeastern Brazil

Grant number: 14/01648-7
Support type:Regular Research Grants
Duration: May 01, 2014 - October 31, 2016
Field of knowledge:Physical Sciences and Mathematics - Geosciences
Principal Investigator:Silvio Takashi Hiruma
Grantee:Silvio Takashi Hiruma
Home Institution: Instituto Geológico. Secretaria do Meio Ambiente (São Paulo - Estado). São Paulo , SP, Brazil
Assoc. researchers:Antonio Luiz Teixeira ; Claudio Riccomini ; José Antonio Ferrari ; Peter Christian Hackspacher

Abstract

The passive continental margin of southeastern Brazil is characterized by a polyphasic tectonic and denudation evolution since the Gondwana breakup, which resulted in a complex geomorphological compartmentation with striking topographic contrast and diversity of landforms. The summits of the Serra do Mar and the Serra da Mantiqueira (Bocaina, Campos do Jordão , campos do Ribeirão Fundo, among others) with altitudes above 1800 m stand out in this landscape. According to the classical geomorphological models, these areas are considered remnants of old erosion surfaces. Paleogeographic reconstruction of these Precambrian crystalline areas is difficult due to the lack of stratigraphic markers. However, the application of low temperature thermocronologic methods, such as the apatite and zircon fission track analyses, permit to obtain the thermal histories of the basement rocks and establish the denudation rates over geologic time. Despite the significant amount of apatite fission track ages in the Bocaina Plateau, thermochronological data in the other summit areas are scarce or unavailable. The aim of this project is to compare the denudation history of these areas by using the apatite and zircon fission track thermochronology with structural and geomorphological analyses. Thus, we expect a better understanding of the evolution of the passive continental margin of southeastern Brazil, as well as revisit the application of classical geomorphological models. (AU)