Paleoenvironmental reconstruction of the Ediacaran-Cambrian transition in the Southwestern part of Gondwana

• Grant number: 22/09290-0
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: November 01, 2023
• End date: July 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Lucas Verissimo Warren
• Grantee: Gabriel Correa Antunes
• Host Institution: Instituto de Geociências e Ciências Exatas (IGCE). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil
• Associated scholarship(s): 24/05052-3 - Paired sulfur isotopes of the Tagatiya Guazú Formation (PY) and Murciélago Group (BO), southwestern Gondwana, BE.EP.DR

Abstract

The transition from the Ediacaran Period to the Cambrian is characterized by profound changes in terrestrial ecosystems, such as disturbances in the carbon and sulfur cycles due to the redox conditions of the oceans, allied to the appearance of the first animals with skeletons and the intense bioturbation of the ocean substrate. The definition of the paleoenvironmental conditions of oxygenation and distribution of nutrients in this interval and their role as evolutionary drivers are currently one of the great challenges of geobiology. At the current stage of knowledge, such a relationship is established based on data collected at different time intervals, that is, by comparing geochemical and paleontological data obtained at different detailing scales, which commonly lack refinement in high resolution. For this purpose, it is necessary to investigate the conditions recorded in each environment in which autochthonous and parautochthonous fossils are found and their comparison with other examples described around the world. In this context, it is opportune to investigate the Tagatiya Guazu Formation (Paraguay) and the Murciélago Group (Bolivia), carbonate units of Ediacaran age positioned on the SW margin of Western Gondwana. Due to the proven potential for geobiological and paleoenvironmental studies of the Tagatiya Guazu Fm., and the unexplored potential of the Murciélago Group, this project proposes a multi-proxy analysis in these units, based on the acquisition of new columnar sections, in addition to the detailing of the already known ones, using stratigraphy techniques combined with isotope data from Ccarb, Corg, SCAS, Spyr and Ocarb, REE+Y and trace metals. The application of these methods will be fundamental in refining the paleoenvironmental interpretation of these units, contributing to the reconstruction of the complex Ediacaran redox and nutrient dynamics and testing the hypotheses of oxygenation/nutrients coevolution and life at the dawn of the Phanerozoic Eon. (AU)