Lithostructural pre-Rhyacian geological targets of the transversal zone (central domain) of the Borborema Province, NE Brazil - phase II

Abstract

The main objective of this project is to proceed the works and studies developed in the last project (2013/09484-0 FAPESP), because the profitable results then obtained.In the first phase (last project) were able to draw an up-to-date general tectonic scheme of the Transversal Zone, the central domain of the Borborema Province. So doing, we have discuss the nature of the branching system of Neoproterozoic orogens of this central domain, where we could point out an early accretionary magmatic arc (to the north of Transversal Zone) and we were able to identify three new paleoproterozoic basement inliers, namely : Sul Coremas, São José do Caiano and São Pedro terrane. Additionally, we could identify some Archean protoliths along the Alto Moxotó terrane. So, we have published three papers. In order to cover the whole problem, we demand a lot of further reseach.For these teconostratigraphic terranes (Alto Moxotó, Sul Coremas, São José do Caiano, S. Pedro) we got some good geological and isotopic data (U/Pb, Sm/Nd, Rb/Sr), but there still are many things to be done, and this is the main reason to ask for a new project. From now on, we know where are and which kind of geological and isotopic investigation will better be indicated. For some particular cases, some geophysical survey will be necessary (to do this, we have ome preliminar understanding with the people of CPRM- Brazilian Geological Survey and people from the UFPE-Nata-RN). We do believe that now, we are able to point out the problems that deserve first priority. For the Alto Moxotó, we have to continue our researches looking to find out some more Archean remnants , within the complex net of Rhyacian (predominating) and Orosirian orogenicc events. For the others terranes, tectonic-themal events of Rhyacian era are predominating ). It is possible and we expect to find other elements of tectonic history of the other terranes (for example, there are some preliminar indications of Siderian tectonic events in the S. José do Caiana terrane).During the last three years, we could perform a data base of hundreds of geochronological information (obtained from ourselves and from the references) that will be useful (of many different ways) to the next phases of research. From all geological maps (1:100,000 scale) performed in the Borborema, we have copies, that will be useful along the next phase of researchWe intend to get geological and isotopic data enough to transform the drafts that we have preliminarily organized (at the end of the first phase of the project), into new real scientific apers .The Borborema Province is very important for the development of the knowledge of branching systems of orogens. Once we will have best data about those pre-Neoproterozoic basement inliers, we will be able to make exercises of comparison with those of Mesoproterozoic (e.g. Grenvillia terranes), Neoproterozoic (e.g. East African Orogen, Damara belt) and even Phanerozoic (e.g. Appalachian and Variscan belts) periods. This is important chapter of the study of Tectonics that is absolutely up to date worldwide. (AU)