CHRONOLOGY OF QUARTZITIC SLOPES FROM MINAS GERAIS, BRAZIL

Auteurs

DOI :

https://doi.org/10.4215/rm2022.e21032

Résumé

Quartzitic mountain reliefs developed in a tropical savanna climate tend to have shallow sedimentary deposits. This is due to low level weathering processes of quartzite rocks and formation of colluvium ramps on the slopes. This study aims to determine the characteristics of colluvial materials, particularly grain size, and to analyze sediment chronology above the saprolite, seeking to identify accumulation rates and make correlations with the dynamics of the recent geomorphological evolution of the Canastra range in Minas Gerais, Brazil. Samples collected in different morphological positions were submitted to granulometric analysis and dated by Optically Stimulated Luminescence Single Aliquote Regeneration (OSL/SAR) and radiocarbon dating. Grain size analysis showed a predominance of sandy and gravel materials and demonstrated that the colluvial ramps in the study area contain materials derived from the decomposition of quartzite rocks, accumulated in shallow and sandy profiles. LOE/SAR dating indicated ages between the end of the Pleistocene, not exceeding 30,500 +/- 4,950 BP, to 500 years BP, whereas the 14C dating showed ages between 4460 +/- 30 BP and 1140 +/- 30 BP. These data indicate that the deposits from the study area are relatively recent, which demonstrate that variations in the weathering process and deposit formation have undergone recent changes, probably due to climatic fluctuations and changes in the regional hydrological regime.

Keywords: Canastra Range, Paleogeomorphological Reconstruction, Weathering of Quartzites, OSL, Tropical Range



Biographies des auteurs

  • Silvio Carlos Rodrigues, Federal University of Uberlândia, Uberlândia (MG), Brazil

    PhD in Sciences (Physical Geography) from the University of São Paulo (1998). He chaired the Union of Brazilian Geomorphology in the biennium 2005/2006. He was a member of the Advisory Committee on Physical Geography of CNPQ (CA-SA) between 2008 and 2010. Member of the Chamber of Natural Resources (CRA) with FAPEMIG between 2014 and 2016. between the years 2008 to 2011, and the second time started in 2020. He is currently a member of the editorial board of GEOUSP magazines, Revista do Departamento de Geografia (USP), Brazilian Geographical Studies. He was a member of the EOLSS International Editorial Council of UNESCO, He was on the Editorial Board of the UFU Publishing House between 2008 and 2011. He is a reviewer for the Brazilian Journal of Geomorphology, Caminhos da Geografia Magazine (UFU. Online), Environmental Earth Sciences (SPRINGER). He was secretary of the Commission On Land Degradation And Desertification of the International Association of Geography between 2010 and 2012. He is currently a Full Professor at the Institute of Geography at the Federal University of Uberlândia, working on undergraduate and graduate courses, as well as a member of the Graduate Program -Graduation in Geography from UFU (Grade 5). He has experience in Geosciences, with an emphasis on Geomorphology, working mainly on the following subjects: geomorphology, geomorphological cartography, soil erosion, integrated environmental analysis and geomorphological mapping.

  • Fabiana Cristina dos Santos, Federal University of Uberlândia, Uberlândia (MG), Brazil

    DOCTOR IN GEOCHEMISTRY (2021) AT THE FEDERAL UNIVERSITY OF UBERLÂNDIA. RESEARCH MEMBER OF THE SOIL GEOMORPHOLOGY AND EROSION LABORATORY (LAGES/UFU).

  • Rui Filipe Ferreira Carvalho, University of Barcelona, Barcelona, Spain

    Professor at the University of Barcelona, acting Physical Geography and Planning.

  • Thallita Isabela Silva Martins Nazar, Federal University of Catalão, Catalão, Catalão, Brazil

    PhD in Geography (2018) by the Graduate Program in Geography at the Federal University of Uberlândia (MG). Master in Geography (2013) by the same institution (UFU). Specialist in Geomatics (2011) with emphasis in Geoprocessing by Faculdade Católica de Uberlândia. Graduated in Geography (Bachelor - 2010 and Bachelor - 2011) from the Federal University of Uberlândia. She has experience in Geomorphology, Geoprocessing and General Physical Geography; she develops works, mainly, in the areas of Geomorphological Cartography, Geocartography, Landscape Analysis, Relief Evolution and Geoheritage. She is a member of the Research Group "Integrated Studies in Geosciences and Geoheritage"-GPAT. Currently, she is Vice-coordinator of the Geography-Baccalaureate Course, Coordinator of the Cartography Laboratory and Coordinator of Extension and Culture at IGEO / UFCAT.

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Publiée

2023-02-15

Numéro

Vol. 21 (2022)

Rubrique

Artigos

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