Evidence for the Central Atlantic magmatic province (CAMP) in Precambrian and Phanerozoic sedimentary basins of the southern Amazonian Craton, Brazil

The Triassic-Jurassic emplacement of large volumes of basaltic rocks termed the Central Atlantic magmatic province (CAMP), preceded the Pangea break-up and the opening of the Central Atlantic Ocean. Central Brazil is an important site where the CAMP record can be assessed in detail. Previously mapped basalts in this region, which includes southwestern Tocantins and southern Tapajós provinces represent a volume of 0.19 million km³. Interpretations of existing geophysical and geological data combined with forward gravity modelling were carried out in the Paleozoic Parecis and late Cryogenian-Cambrian Araras-Alto Paraguay basins. This study allows a new interpretation of geologic structures from residual gravity anomalies in the southern Amazonian Craton. Additionally, the basalts exposed in these basins occur as lava flows, sills and dykes hosted in Neoproterozoic and Paleozoic rocks, presenting an estimated subsurface magma volume of 3 million km³. Moreover, these geological elements are interpreted as high-density rocks correlated to the continental tholeiitic flood basalts of the CAMP. Therefore, the combination of residual gravity anomalies and previous geological data verifies the CAMP occurrence in these sedimentary basins of Amazonia.