Tectonic framework of the Paraná basin unveiled from gravity and magnetic data

Abstract

The Paraná Basin, one of the most important Brazilian sedimentary basins, was created during the formation of Western Gondwana. Until recently, its tectonic framework has been studied mainly through indirect studies using geophysical data such as gravity, magnetic, as well as seismic reflection, and bore hole data. However, the last years, new geophysical data with better resolution became available, enabling new studies on the Brazilian sedimentary basins. To this end, the objective of this work is to contribute with new information on regarding the central and northern areas of the Parana basin and to investigate the major tectonic structures of its basement, as to understand the role of the Precambrian basement structures on its reactivation and geodynamics. For this purpose, quantitative and qualitative analysis of gravity and magnetic data were conducted using the Matched-Filter technique associated with enhancement filters, such as Total Horizontal Gradient and Tilt Derivative of the Total Horizontal Gradient. These geophysical products allowed interpreting the main geophysical lineaments and their depth. We identified structural patterns related to basement reactivation associated with the evolution of Western Gondwana. The NNE-SSW trending structures are related to reactivations of the Transbrasiliano and Paraíba do Sul Strike-slip Systems in the Late Ordovician. The NW-SE trending lineaments were generated with the tectonic growth of the Western Gondwana in the Triassic to the Late Jurassic, which started in the region of the Ponta Grossa Arch. This event was followed by the intracontinental magmatism in the Early Cretaceous. The E-W trending structures are related to the drifting of the South American Plate in the Late Cretaceous-Neogene and the faults originated from it, forming dextral binaries inside the plate pertaining to the Neotectonic Strike-slip System. The NNE-SSW, NE-SW, and NW-SE trending lineaments close to the border between the Paranapanema Block, the Goiano Domain, and the Araguaia, Paraguay, Brasília and Ribeira Belts are associated with suture zones. Thus, this work provides additional information related to the continuity of fault systems and crustal domain limits, as well as the extent of the crustal blocks in the basement of the Paraná Basin. It highlights the reactivation influence of the structures inherited from the Precambrian basement based on the results from both, gravity and magnetic data.