Foreland deposits, orogenic migration, metamorphism and exhumation: passive margin of the Southern Brasília Orogen

• Grant number: 20/04843-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): November 01, 2020
• Effective date (End): October 31, 2021
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Mario da Costa Campos Neto
• Grantee: Gabriela Vidigal Martinho
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 15/03737-0 - The Rio de La Plata Craton and the Western Gondwana Assembly, AP.TEM

Abstract

The Southern Brasília Orogen is a record of convergence within the margins of the SãoFrancisco and Paranapanema paleoplates, recognized as a neoproterozoic subduction andcollision tectonic wedge located at the edge of the São Francisco Craton. From the Ediacaran(635Ma) it began to set up a system of nappes from high to ultra-high temperature and highpressure transported along the craton edge and a foreland basin system in which immaturemetasedimentary sequences cover passive margin psamo-pelitic units in discordance. The studyof sedimentary provenance in foreland basins is widely used as a tool to investigate orogenicmigration and, in this project; the focus will be the analysis of the immature sedimentary unit(metawackes) imbricating in the Luminárias and Carrancas Nappes and in the distal fold-andthrustbelt at the southern edge of the São Francisco Craton. This unit is as an exotic sequence tothe psamo-pelitic passive depositional system and its characterization is useful to investigate thesource area of the sedimentary contribution, which will be done through the study of detritalzircon crystals by geochronology U-Pb (LA-ICP-MS). This project seeks to recognize, in thedomain of the passive margin of the Southern Brasília Orogen, different depocenters and/or theirtectonic migration, in addition to studying the deformation in the basins due to the advancingprocesses of the tectonic overload by the thrust front and the uplift of the orogen. Themetamorphic and deformation study will also be carried out, focusing on microtectonics andtextural analysis by microscopic petrography. The proposal aims at studying the paleogeographyorganization of the frontal foreland deposits and the exhumation of the orogenic hinterland of theSouthern Brasília Orogen.