Tracking sea level changes in Fernando de Noronha Archipelag using grain-size and mineral distribution

• Grant number: 23/12421-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2023
• End date: October 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Geological Oceanography
• Principal Investigator: Luigi Jovane
• Grantee: Debora Ferreira Quina
• 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

Tropical regions are an important source of heat for the middle and high latitudes. The Atlantic Ocean-Atmosphere system is unique as it's the only system currently transporting heat across the equator. Therefore, it's crucial to perform accurate climate reconstructions, documentation, and implementation of Atlantic climates in large-scale climate models. However, this has been challenging for most of the Cenozoic due to the lack of sufficient records from low-latitude sediments. Here, we propose to investigate paleoceanographic changes throughout the Cenozoic, driven by both long-term and short-term forcings, from the high greenhouse gas conditions in the Eocene to Quaternary glaciations, by reconstructing atmospheric, oceanographic, and biological processes. The Brazil Margin is a stable and passive continental margin that developed after the opening of the central Atlantic Ocean in the mid-Cretaceous. An intriguing aspect of this margin is that it has remained tectonically "passive" and approximately at the same equatorial latitude since its formation, maintaining a predominantly oligotrophic intertropical environment continuously. This project will leverage these unique attributes to obtain high-quality sedimentological, paleoclimatic, and paleoceanographic data for the Cenozoic by proposing drilling transects through the Brazil Margin from the highest part of the continental slope to the abyssal plain. The expected stratigraphic continuity along these transects will allow for a detailed study of the relationship between pCO2, sea level, and climate changes throughout the Cenozoic, constraining the fundamental parameters for calculating climate sensitivity. These stratigraphic records will define the low-latitude climatic response to key Cenozoic climate events such as the EECO, MECO, EOT, OMT, MCO, and iNHG (see text for details). The sediments are expected to yield calcareous and organic microfossils, enabling the study of tropical ecosystem responses to these climate events and providing independent substrates for climate and carbon cycle reconstructions. The sediments will also contain fine aeolian particles and terrigenous sediments related to increased runoff, hence more precipitation, associated with the South American Monsoon System as part of the Global Monsoon System. By conducting a depth transect from selected locations based on seismic reflection data, integrated with high-resolution sedimentological records to reconstruct sea level changes. In particular, these sites were chosen to establish a benchmark for recent high-resolution tropical climate reconstructions from the Eocene, which will yield the following results: 1) detailing the relationship between tropical climate (temperature), sea level, and atmospheric pCO2; 2) evolution of the Atlantic Meridional Overturning Circulation, driven by long-term (tectonic) and short-term (solar insolation) forcings and its interaction with the South American Monsoon System.