Jaibaras tectonossequence genesis (Ediacarano - Ordoviciano) and its inheritance in the sedimentation of Serra Grande sequence (Ordoviciano - Siluriano), Northeast edge of Parnaíba Basin

Abstract

The Jaibaras Basin is usually interpreted as the precursor unit of the Parnaíba Basin, being separated by a regional disagreement. Distensive efforts occurring after the final stages of Gondwana consolidation in the Ediacaran Period would be responsible for the formation of numerous small-sized rift basins possibly from faults and discontinuities of the transbrasilian lineament. At a later stage, a phase of thermal subsidence in the Ordovician would have begun the implantation of the Parnaíba Basin, covering the sedimentary successions deposited in the rift basins. However, the full acceptance of the hypothesis that the Jaibaras Basin is the precursor of the Parnaíba Basin is hampered by the absence of an adequate stratigraphic framework, as well as by the absence of consistent geochronological data in the two basins. This project aimed to understand this hypothesis through detailed sedimentary, stratigraphic and geochronological studies in the Ediacaran - Ordovician sedimentary sequences of the Jaibaras Basin and pre - Devonian units of the Parnaíba Basin. It is proposed, therefore, the use of modern basin and basin analysis methods in sequence stratigraphy, together with geochronological and sedimentary provenance analyzes to compose an appropriate depositional framework. In this way, the present project aims to fill this important knowledge gap and seeks to understand the mechanisms involved in the transition between rift basins and intracontinental basins installed after the final consolidation of the Gonwana supercontinent. (AU)