The Cryogenian and Ediacaran Records From the Amazon Palaeocontinent

Abstract

The Amazon Craton was involved in the buildup of the Rodinia and Gondwana supercontinents during the Neoproterozoic. During this era, Earth’s surface was marked by important transformations including global glaciations, atmospheric and ocean oxygenation pulses, and the turnover of life forms. Most of these events were recorded on the margins of the Amazon Palaeocontinent in the time interval between the breakup of Rodinia and the assembly of Gondwana, today located on its southeastern border as part of the Paraguai Fold–Thrust Belt. This paper reports the age constraints obtained for the respective sedimentary successions based on several tools, including geochronology using U–Pb, Pb–Pb, and Ar–Ar methods, isotope chemostratigraphy of C and Sr, and palaeobiology. According to the results, the sedimentary successions record surface conditions from the early Cryogenian to the early Cambrian.