Cenozoic landscape evolution in the Paulista Peripheral Depression, São Paulo (Brazil)

• Grant number: 25/05935-5
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: September 01, 2025
• End date: August 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Physical Geography
• Principal Investigator: Fabiano Tomazini da Conceição
• Grantee: Vinícius Borges Moreira
• Supervisor: Paulo Marcos de Paula Vasconcelos
• Host Institution: Instituto de Geociências e Ciências Exatas (IGCE). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil
• Institution abroad: University of Queensland, Brisbane (UQ), Australia
• Associated to the scholarship: 23/18273-5 - Understanding the dynamics of deposition in alluvial rivers near to different cuestiform sectors in the Paulista Peripheral Depression, BP.PD

Abstract

The Cuestiform relief in the Paulista Peripheral Depression (PPD), state of São Paulo, Brazil, is a geomorphological feature that separates areas in the west overlain by Parana flood basalt sequences and dissected areas on the east from where the thick basalt sequence has been completely eroded. The timing and rate of the erosive processes that produced the PPD, and the direction of sediment removal, is essential for understanding the formation and evolution of sedimentary basins in the South Atlantic. The landscape in the region hosts three erosion paleosurfaces: the Cimeira (1000 - 950 m), Urucaia (750 - 700 m) and Rio Claro surfaces (650 - 600 m). These erosion surfaces record the pace at which the PPD was carved, and the geomorphological and tectonic processes that may have produced such pronounced stepped landscape. To identify and quantify the processes that shaped the landscape in the PPD, I propose to carry out lithological and mineralogical characterization and analysis, weathering geochronology (Mn-oxide 40Ar/39Ar and goethite (U-Th)/He), and cosmogenic isotope (3He in goethite and 10Be and 26Al in quartz) and combine these results with geodynamic models to determine the amount and timing of the weathering and erosion processes that carved the depression. The work will be conducted in three stages: (i) sampling of supergene manganese oxides (MnOx) and 40Ar/39Ar dating of Cimeira Surface, refining its minimum age; (ii) measure rates of erosion on the three paleosurfaces and the present river channels through the analysis of cosmogenic 3He in goethite or hematite and 10Be and 26Al in quartz; (iii) estimate rates of escarpment retreat (horizontal denudation) from the cosmogenic isotope measurements in (ii). The combined application of these complementary analytical techniques to identify and quantify the main processes that produced the Cuestiform relief in this region will produce and new methodological approach useful in the study of landscapes of in similar areas in Brazil and elsewhere. (AU)