Landscape evolution and sediment routing systems during the early stages of the South Atlantic passive margin development in Angola and Northeastern Brazil

• Grant number: 23/00672-0
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2023
• End date: April 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Agreement: University of Manchester
• Mobility Program: SPRINT - Projetos de pesquisa - Mobilidade
• Principal Investigator: Renato Paes de Almeida
• Grantee: Renato Paes de Almeida
• Principal researcher abroad: Stefan Schroeder
• Institution abroad: University of Manchester, England
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Liliane Janikian Paes de Almeida
• Associated research grant: 18/23899-2 - Trans-Amazon Drilling Project: origin and evolution of the forests, climate, and hydrology of the South American tropics, AP.PFPMCG.TEM

Abstract

The southern Atlantic continental margins contain areas of elevated topography (Bié dome in SW Angola, Borborema plateau in NE Brazil). The origin of this anomalous topography outside areas of active tectonism is controversial: it may be a remnant of tectonic uplift during rifting in the Early Cretaceous, or linked to younger (Upper Cretaceous and/or Neogene) uplift events likely driven by dynamic topography and mantle convection processes. The role of climate in shaping this topography remains untested. Our study will tie together geomorphological and sedimentary records of uplift, climate, erosion and sediment delivery with topography and basin modelling to test the relative influence of climate vs mantle processes on topography.During reciprocal research visits to Sao Paulo and UoM we will carry out joint analysis of remote sensing (satellite images, digital elevation models, geological maps) and sedimentary data sets to constrain the record of uplift, erosion and sedimentation. Detailed topography mapping will identify preserved paleo-erosion surfaces, uplifted marine terraces, and any marine sediments 'stranded' at elevation.We will identify volumes and timing of sedimentation and erosion events from preserved sedimentary stratigraphy in outcrop, well and seismic data, as well as published and unpublished detrital zircon U-Pb ages and detrital apatite fission track data. Zircon and apatite data are available for Brazil, but only partly in Angola, where they will be the focus of follow-up research.We will use joint field work in Brazil and Angola to ground truth the observations from remote sensing data. Key outcrop sections will be analyzed to identify evidence for erosion and sediment delivery. The field work will further serve to collect samples for a follow-up petrographic and geochemical source to sink study, integrating the sedimentary record of onshore basins to their offshore counterparts.A final research visit to Brazil will be used to carry out numerical landscape and basin modelling with the input data collected in the earlier laboratory and field visits, combined with literature information on paleoclimate. Modelling will develop scenarios for topography evolution through time, and test the effects of postulated uplift events and climate on the sedimentary record. This final exchange visit will also serve to write drafts of publications from the pilot data, as well as to discuss a joint follow-up research proposal. (AU)