| Grant number: | 17/21440-0 |
| Support type: | Regular Research Grants |
| Duration: | May 01, 2018 - July 31, 2020 |
| Field of knowledge: | Physical Sciences and Mathematics - Geosciences - Geology |
| Principal Investigator: | Carlos José Archanjo |
| Grantee: | Carlos José Archanjo |
| Home Institution: | Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil |
| Assoc. researchers: | Maria Helena Bezerra Maia de Hollanda |
Abstract
Contrasting tectonic models have been proposed for the evolution of the basement of the Parnaíba Basin (PI-CE). Based on gravimetric and seismic data, one model proposes that the basement accommodated rifting processes succeeded by thermal subsidence, whereas alternative models stand that the Parnaíba Basin evolved mostly by lithospheric flexure induced by a dense lower crust. The distinction between these models has important consequences in defining the thermal history of the basin and, therefore, to guide the research of oil and gas. Adopting the "rifting model" implies that a thermal anomaly would induce crustal uplift, (trans)tensional deformation, emplacement of magmatic (plutonic and volcanic) rocks and development of rifted basins that, in the Ceará Central crustal domain, would have occurred in the transition between the Ediacaran and the Cambrian-Ordovician. This project is focused on geophysical (anisotropy of magnetic susceptibility and remanence) and geochronological (U-Pb and 40Ar/39Ar) methods to: (i) link the emplacement of late shallow plutons and dikes with the regional deformation localized mostly in ductile to brittle shear zones, (ii) define the crystallization age of the plutons and dikes and its subsequent exhumation histories, and (iii) identify sources and depositional ages of detrital zircon in molasse-type basins (Cococi and Jaibaras troughs). These results must reconcile the tectonic evolution of the basement during the final stages of the Brasiliano orogeny of the Ceará Central and shed light on the initial stages of Parnaíba basin evolution. (AU)