Northeast Sao Francisco Craton and West-Congo Craton linked before the Rhyacian (2.10-2.04 Ga) orogeny: Evidences from provenance and U-Pb ages of supracrustal rocks from the Rio Capim greenstone belt, Serrinha Block

摘要

The period between the Rhyacian and Orosirian is known for the development of many orogenic belts and supracrustal sequences, which can be found in different cratons worldwide. In the northern part of the Sao Francisco Craton, there occur several Rhyacian-Orosirian sedimentary sequences associated with the orogenies that amalgamated the precursors of the Sao Francisco and West-Congo Cratons. However, little is known about the time and tectonic setting of sediment deposition. In this study we present U-Pb detrital zircon ages and provenance studies of sedimentary successions from the Paleoprotemzoic Rio Capim greenstone belt, Serrinha Block, Sao Francisco Craton, Brazil. Detrital zircon data reveal a main sedimentary source of ages between 2.20 and 2.12 Ga, and indicate protoliths deposition between 2106 and 2086 Ma in a pro-foreland type basin. The main age interval matches the arc-related magmatism of the Rio Capim and Rio Itapicuru greenstone belts. Additionally, an age interval of 2.35-2.25 Ga indicates a sedimentary contribution of unknown source, while ages between 2.8 and 3.2 Ga suggest the Archean basement source. Field features, U-Pb ages and major and trace elements data support the interpretation that the Rio Capim and Rio Itapicuru greenstone belt both could make up an arc complex. Lithostratigraphic and tectonic matches allow to suggesting that the Serrinha Block may have an African counterpart, namely the Ntem-Chaillu Block, West-Congo Craton.