Stromatolites in the Carbonate Succession in the north of the Paraguay belt: paleoenvironment, geochemistry and implications for post-glacial events of the Neoproterozoic

Abstract

Understanding the Neoproterozoic takes on importance since rocks from this period were evidence of extreme and unique paleoclimatic events in Earth's geological record, which influence on the life story has not been properly clarified. This doctoral proposal aims to understand part of this history with the study of microbialites and associated structures in Araras Group, in the northern part of the Paraguay Belt (neoproterozoic tectonic unity). For this the microbialites will be described at different scales(macroscopic, mesoscopic, microscopic), the possible occurrence of microfossils in microbialites in Nobres Formation (Araras Group terminal unit)will be analyzed, the isotopic records in horizons with microbialites in Araras Group will be reevaluated and expanded, and a detailed isotopic characterization of C and O of the enigmatic tube structure will be made , these structures occur in microbialites in the base of the Araras Group (Mirassol D´Oeste Formation), these structures are apparently restricted to the beginning of the Ediacaran (in cap carbonate layers that occur after the Marinoan glaciation) in various parts of the world. With this analysis is we expect to help to clarify the paleoenvironmental evolution in Araras Group and connect the interpretations obtained with global events. (AU)