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Weathering geochronology of ferruginous duricrusts from the Alto Paranaíba region, Minas Gerais, Brazil

Grant number: 19/13943-7
Support type:Scholarships abroad - Research Internship - Doctorate
Effective date (Start): August 01, 2020
Effective date (End): October 05, 2020
Field of knowledge:Agronomical Sciences - Agronomy - Soil Science
Principal Investigator:Pablo Vidal Torrado
Grantee:Karina Patrícia Prazeres Marques
Supervisor abroad: Maria Giuditta Fellin
Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
Local de pesquisa : Swiss Federal Institute of Technology Zurich, Switzerland  
Associated to the scholarship:17/22292-4 - Geology-Geomorphology-Pedology relationship associated with oxisols genesis of the West of Minas Gerais, BP.DR

Abstract

Ferruginous duricrusts are ubiquitous in relict paleosurfaces along humid/semi-humid tropical and subtropical zone, such as in South America, India, Africa and Australia. Many of the remnants of relict paleosurfaces are related to the Sulamericana Surface, which are considered to be formed in the Paleogene. However, their chronology was long derived from their location in the landscape and relative inferences. During weathering secondary supergene minerals precipitate in ferruginous duricrusts, such as iron oxides and hydroxides (hematite or goethite) and clays (kaolinite and gibbsite), often in a polycrystalline arrangement. Thus dating of these minerals can be useful to reveal the long and complex history of ferruginous duricrusts formation and their relation to paleoclimates and long-term landscape evolution. Our main objective is to dating goethite or hematite grains of different generations from ferruginous duricrusts occurring in relict paleosurfaces of the western Minas Gerais state (Brazil). Occurrence sites of ferruginous duricrusts in a representative catchment of the Alto Paranaíba region (Minas Gerais state, Brazil), named Quebra Anzol, were selected. Samples of ferruginous duricrusts from layers of different profiles will be selected and the U, Th and He content in goethite and hematite grains of different generations will be measure to estimate their apparent age. The analyses will be carried out in the Institute of Geochemistry and Petrology at the ETH Zurich (Switzerland) under the supervision of Dr. Maria Giuditta Fellin.