Paleomagnetism and geochronology of the Bebedouro cap carbonate: evidence for continental-scale Cambrian remagnetization in the Sمo Francisco craton, Brazil

New Pb–Pb ages, rock magnetic, and paleomagnetic data were obtained on Neoproterozoic carbonates of the Salitre Formation which conformably overlie the glacial rocks of the Bebedouro Formation in undeformed areas of the Irecê basin, São Francisco craton. These data give new supporting evidence for a large-scale remagnetization and resetting of the U–Pb isotopic system at Cambrian times along the São Francisco and Irecê basins, which cover more than 300,000 km2 of the São Francisco craton surface. A 207Pb–206Pb isochron age of 514±33 Ma was on undeformed, stromatolitic carbonates from the Salitre Formation. Although samples from other sites give almost non-radiogenic Pb signatures, they fall at the lower end of this line. Rock magnetic properties obtained for most of the sites are typical of remagnetized carbonates, and include: wasp-waisted hysteresis loops, contradictory Lowrie–Fuller and Cisowski tests, and anomalously high hysteresis ratios. Some samples, however, have presented only some of these magnetic characteristics. Four magnetic components (A, B, C, and D) were isolated from the Salitre carbonates. Three of them (A, B, and C) are comparable to previous results from the correlative Bambuı́ carbonates, which crop out ca. 600 km southward. The component C, carried by fine-grained SD-PSD magnetite, was identified at 23 sites. It directs steeply positive to the northeast, giving a paleomagnetic pole (SaC) at 33°N, 323°E (α95=4.0°, k=23.6). The SaC pole overlaps with that obtained from component C of Bambuı́ carbonates (BaC pole: 30°N, 321°E, α95=3.8°). The paleopoles from component B of Salitre (SaB) and Bambuı́ (BaB) also lie close but are statistically different. After rotation of South America to Africa, all these poles fall close to the ∼520 Ma segment of the Gondwana apparent polar wander path, suggesting that the resetting of the isotopic and magnetic systems in the Neoproterozoic carbonates of the São Francisco craton occurred at that time. The single polarity directions found along the whole sedimentary succession in both areas give additional support for rapid remagnetization events. We suggest that paleomagnetic data and most of the Pb–Pb isochron ages in the São Francisco carbonates recorded a regional-scale fluid migration event, in the aftermath of the Brasiliano (Panafrican) collision. This fluid-flow event may also have concurred for the genesis of the Pb–Zn mineralizations found across the basin.