U–Pb LA-ICP-MS detrital zircon ages of the São João del Rei and Carandaí basins: New evidence of intermittent Proterozoic rifting in the São Francisco paleocontinent

Constraints from zircon geochronology on the tectonic evolution of the Borborema Province (NE Brazil): Widespread intracontinental Neoproterozoic reworking of a Paleoproterozoic accretionary orogen

“…2.2e2.0 Ga orogenic events and can be interpreted as an abortive attempt to continental fragmentation. These events are of similar age to the main event of crustal rifting in the São Francisco Craton that produced the Espinhaço basin (Danderfer et al, 2009;Chemale et al, 2012;Ribeiro et al, 2013). (ii) To date, no episodes, whether intraplate or orogenic, in the interval between 1.5 and 1.1 Ga was identified in the Borborema Province, suggesting a long period of crustal stability.…”

“…Alternatively, Mesoproterozoic zircons could have distal provenance. In this case, sources located either in the São Francisco Craton, where recent studies show that several episodes of rifting occurred between 1.8 and 0.9 Ga (Danderfer et al, 2009;Chemale et al, 2012;Ribeiro et al, 2013), or in the SW Amazonian Craton, where Mesoproterozoic rocks predominate (J.O.S. Santos et al, 2008), could be envisaged.…”

The Ribeira Belt

“…Originally interpreted as glacial deposits (Leonardos 1940), these diamictites occur in close association with fault zones and are unconformably covered by the Barroso Limestone and Prados Pelites. According to Ribeiro et al (2013), the Carandaí Diamictites more likely represent debris-flow deposits associated with normal fault scarps developed during a renewed rifting episode.…”

“…According to Ribeiro et al (2013), the São João Del Rey Group, as a correlative of the middle Espinhaço Supergroup Complex; e hornblende granodiorite orthogneisses of the Quirino complex, with mafic enclaves; f foliated variety of the Quirino Complex with a kinematic indication of top to NW; g, h orthogneisses and amphibolite layers and boudins of the Região dos Lagos complex exposed in the Paramirim aulacogen and Araçuaí belt (see Cruz and Alkmim, and Alkmim et al, this book), records rift and sag events experienced by the São Francisco landmass in the course of the Mesoproterozoic. As indicated by their lithofacies architecture and field relationships, the Tiradentes and Carandaí formations accumulated during two major rifting pulses that took place, respectively, in the Calymmian Period, and sometime after 1379 Ma, followed by periods of thermally driven subsidence of the basin system.…”

“…Assemblages: The Andrelândia Megasequence The Neoproterozoic Andrelândia megasequence (Ebert 1984;Paciullo 1997;Paciullo et al 2000;Ribeiro et al 2013) consists mainly of siliciclastic metasedimentary rocks that occur in the interference zone between the Ribeira and southern Brasília belt (Trouw et al , 2013Campos Neto and Caby 2000), as well as within thrust sheets of eastern Occidental terrane. The sequence stratigraphy model discussed here is based on detailed mapping of lithofacies associations and their bounding unconformity surfaces (Figs.…”