Sea-Level changes and Global Monsoon System: Clues from marine cores in Brazil

• Grant number: 24/05164-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2024
• End date: April 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Geological Oceanography
• Principal Investigator: Luigi Jovane
• Grantee: Virgínia Soares Gomes
• 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 a major source of heat to mid- and high-latitudes. The Atlantic OceanAtmosphere system is unique as it is the only system that currently transports heat across theequator. Therefore, accomplishing accurate global climate reconstructions, documentation andimplementation of Atlantic climates in large-scale climate models is essential. This, however,has been hampered for most of the Cenozoic due to the lack of sufficient low-latitude sedimentrecords. Here we propose to investigate paleoceanographic changes across the Cenozoic drivenby longer and shorter term forcings from the Eocene greenhouse to icehouse conditions in theQuaternary, through the reconstruction of atmospheric, oceanographic and biological processes.The Brazilian Margin is a passive and stable continental margin that developed following theopening of the central Atlantic Ocean in mid-Cretaceous. A peculiar aspect of this margin is thatit remained tectonically "passive" and approximately at the same equatorial latitude since itsformation and, consequently, it has maintained continually a mainly oligotrophic inter-tropicalenvironment. This project will take advantage of these unique attributes for obtaining highquality sedimentological, paleoclimatic, and paleoceanographic data for the Cenozoic, proposingto drill transects across the Brazilian Margin from the uppermost part of the continental slope tothe abyssal plain. The expected stratigraphic continuity along these transects will allow thedetailed study of the relation between pCO2, sea-level and climate changes throughout theCenozoic by constraining the fundamental parameters for calculating the climate sensitivity. Thisstratigraphic record will define the low-latitude climatic response to the major Cenozoic climaticevents, such as the EECO, MECO, EOT, OMT, MCO and iNHG (see text for details). Sedimentsare expected to yield calcareous and organic microfossils, which will allow for studying theresponse of tropical ecosystems to these climatic events and also provide independent substratesfor climate and carbon cycle reconstructions. Sediments will contain also fine eolian particles aswell as terrigenous sediments related to increased run-off therefore more precipitations, whichare associated to the South American Monsoon System as part of the Global Monsoon System.By undertaking a depth transect of sites selected from a wealth of seismic reflection data,integrated with high-resolution sedimentological records to reconstruct sea-level changes. Inparticular, these sites were chosen to establish a landmark for high-resolution Eocene-Recenttropical climate reconstructions, which will provide the following outcomes: 1) detail therelationship between tropical climate (temperature), sea-level and atmospheric pCO2; 2)evolution of the Atlantic Meridional Overturning Circulation driven by longer (tectonic) andshorter term (solar input) forcings and interplay with the South American Monsoon System.