Grain Size Analysis of Sedimentary Variations during the Eocene-Oligocene Transition in Core 900A (ODP Expedition 149, Iberian Peninsula)

• Grant number: 25/01502-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Geological Oceanography
• Principal Investigator: Luigi Jovane
• Grantee: Priscila Ponte Fermino
• 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

The Eocene-Oligocene Transition (EOT) was marked by significant global cooling associated with the formation of the first ice sheet in Antarctica, resulting in a climatic shift from greenhouse conditions to a glacial climate. This event, which occurred approximately 34 million years ago, is characterized by major paleoceanographic changes, such as a sea-level drop of about 40 meters, exposing coastal areas. In the Iberian Abyssal Plain, sea-level fluctuations during the EOT played a crucial role in the dynamics of oceanic currents, leading to the evolution of depositional processes. While the literature predominantly describes pelagic sedimentation during the Eocene, a transition to turbiditic and contouritic deposits is observed in the Oligocene. However, a detailed characterization of this transition in the sedimentary record remains limited, highlighting the need to investigate the interactions between sea-level variations, paleoceanographic processes, and marine sedimentation in the region. In this context, the present project proposes a grain-size and morphometric analysis of samples from Core 900A, obtained during Expedition 149 of the Ocean Drilling Program (ODP). Analyses will be performed using laser diffraction techniques to correlate variations in particle size and shape with sedimentation processes and the reorganization of oceanic currents during the EOT. The expected results include the identification of grain-size and morphometric patterns that will provide insights into sedimentary and paleoenvironmental changes, offering new perspectives on the depositional processes that shaped the Iberian Abyssal Plain during the EOT.