Paleomagnetic study of geological units from South America: implications to the formation of Columbia and Rodinia supercontinents

Abstract

This Project aims to establish the geodynamic evolution of the Amazonian Craton, the Rio Apa Block and the São Francisco Craton in the formation of supercontinents during Proterozoic, using key paleomagnetic poles and U-Pb geochronology in monominerals. The paleomagnetic data will allow test the geodynamic models proposed for these cratonic units, placing them in global paleogeographic reconstructions, such as the configurations of Columbia and Rodinia supercontinents. The targets chosen for the study are non-(or slightly) deformed intrusive and extrusive bodies of different ages, located in key areas. The following geological units from the Amazonian Craton will be studied: (i) the 1780-1790 Ma Vespor Intrusive Suite and Colider Group, located in the Central-Brazil shield, (ii) the 1570 Ma Mata-Matá mafic sill located in the southern Amazonas State, (iii) the Mesoproterozoic Arinos mafic sills and sedimentary rocks from the Dardanelos Formation, and (iv) the Trincheira mafic-ultramafic Complex and the 1230 Ma (U-Pb - baddeleyite) Canamã Intrusive Suite, both located in the northwestern Mato Grosso State. The age of the Trincheira Complex is yet uncertain. It may be correlated to the 1350 Ma Colorado Complex, situated in the Rondonia State, close to the frontier with the Mato Grosso State. In the São Francisco Craton, granitic bodies intrusive in the Serrinha Block (Bahia), and dated between 2160 and 2050 Ma, will be studied. We also intend to continue the studies previously initiated in the following units: (i) the 1110 Ma Rio Perdido dyke swarm (Rio Apa Block), situated to the south of the Bonito city (MS), (ii) the 1110 Ma Huanchaca mafic sills and dykes, located in the Ricardo Franco mountain range (MT) and (iii) felsic rocks from the 1752 Ma Novo Horizonte Formation (Bahia - São Francisco Craton). Eventually, other units may be part of the work, depending on the obtained results and interpretive complexities. In principle, a post-doc, two doctoral students and two undergraduate students will be involved in this project. Eight field works are planned for sampling the target areas, with the participation of geologists with experience in the geological mapping of the respective areas. (AU)