Basement related faults and deformation patterns during the drift phase of Divergent Margins

• Grant number: 23/16060-4
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: February 01, 2024
• End date: May 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Luigi Jovane
• Grantee: Pedro Gouveia Bauli
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 16/24946-9 - Sea-level changes and Global Monsoon System: clues from marine cores in Brazil, AP.PFPMCG.TEM

Abstract

Basins on Divergent Margins are currently located within the interior of a lithospheric plate (i.e., in the drift stage). Consequently, they exhibit less deformation compared to basins situated on Convergent or Transform Margins. However, a basin in its drift phase is also susceptible to intraplate stress, which can induce significant deformation in its sediments. An illustrative example is the Campos Basin (offshore Southeast Brazil), which has been in its drift phase since the Lower Cretaceous. Through a preliminary analysis conducted by this project, unpublished Cenozoic faults with an apparent vertical throw on the order of tens of meters were identified in this basin. These faults are situated on the continental shelf, with most of them centered above pre-existing structures of the bacinal crystalline basement. Nevertheless, the role of basement faults in sediment deformation during the drift phase of Divergent Margins remains poorly understood in the scientific literature. Moreover, Cenozoic deformation on the Brazilian continental shelf is sparsely mapped. Therefore, this study aims to integrate high and low penetration seismic data to conduct a detailed structural analysis about the growth history of these faults: from their rooting near the basement to their current behavior in the Quaternary. The Campos Basin will serve as a case study, enabling a comprehensive investigation into the relationship between the crystalline basement and drift deformation in divergent margins, in terms of deformational styles and potential triggering agents. This study will also contribute to the methodological mapping of Cenozoic structures on the Brazilian continental shelf and have practical implications for the oil industry and for researches on tectonosedimentary processes during the drift stage of the Brazilian Continental Margin.