CHARACTERIZATION OF HUMID EPISODES IN THE CRETACEOUS BASED ON PALEOSOLS AND ICHNOFOSSILS

• Grant number: 22/16353-9
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): April 01, 2023
• Effective date (End): March 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Mario Luis Assine
• Grantee: Diego Luciano do Nascimento
• Host Institution: Instituto de Geociências e Ciências Exatas (IGCE). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil

Abstract

The Cretaceous (145.5 - 65.5 Ma) was a period characterized by several environmental changes triggered by intense volcanic and tectonic activity. The occurrence of large igneous provinces (LIPs) had a significant impact on the concentrations of greenhouse gases, including carbon dioxide (CO2), raising the temperature of the planet. Despite the dominance of arid and semi-arid conditions, multiple lines of evidence suggest the occurrence of abrupt sea surface cooling events, cold snaps, and increased humidity in terrestrial ecosystems during the Cretaceous. In this project, the aim is the identification and characterization of these wet episodes for the Brazilian continental Cretaceous from the detailed study of paleosols and trace fossils from the Bauru, Sanfranciscana, and Araripe Basins. Based on an interdisciplinary approach, macromorphological, micromorphological and geochemical characterization of paleosols (XRD and XRF) will be carried out, aiming at the application of paleoprecipitation and paleoweathering indices, as well scanning electron microscopy and energy dispersive x-ray spectroscopy (SEM/EDS) in slides and samples. The ichnofossils will be described in the field and in the laboratory, using hand samples and thin slides for micromorphological analyzes aimed at identifying likely producers and the environmental controls in their distribution. At the end of this project, it is expected that the data obtained will contribute to the understanding of wet episodes, as well the role of the equatorial wet belt in terrestrial ecosystems from the Aptian to the Maastrichtian.