BUSCADOR RECOLECTA

Digital.CSIC. Repositorio Institucional del CSIC

oai:digital.csic.es:10261/274973

Dataset acquired in 2015 and 2016. The processed datafiles (EDI format) were produced in 2016, except station B10, which was processed in 2017 The electromagnetic time series were collected: 2015, May 8 – May 29: NBPB, B01, B02, B03, B04, B05, B06, B08, B07, B09, NBPN 2015, Oct 30 – Nov 24: NBPB, B09, B04, B02, B01 (Repeated sites because problems with equipment) 2016, April 5 – May 8: B10, B11 All data were acquired along a NS profile in NE Brazil, crossing the States of Ceará, Pernambuco and Bahia. The profile is located between the towns of Pedra Branca (Ceará) in the North and Ponto Novo (Bahia) in the South, with stations installed some 60 km apart. The detailed coordinates are: B10: 4.966023 S, 39.607355 W NBPB: 5.543220 S, 39.583642 W B11: 5.993708 S, 39.510808 W B01: 6.16795 S, 39.409718 W B02: 6.641967 S, 39.340252 W B03: 7.047250 S, 39.497515 W B04: 7.575410 S, 39.674567 W B05: 8.099855 S, 39.897795 W B06: 8.632793 S, 40.224745 W B08: 9.145030 S, 40.373532 W B07: 9.615040 S, 40.383048 W B09: 10.214183 S, 40.205405 W NBPN: 10.846805 S, 40.198437 W, Objectives: The main goal was to investigate the regional setting in Eastern Borborema to study the uplift of the Araripe Basin. Another goal of the BODES experiment was to build integrated geophysical images of the Borborema Province’s crust and lithospheric mantle in order to improve our understanding of its geodynamic and tectonic evolution. Conclusions: We have interpreted the high conductivities under the Araripe Basin as an indication of shallow, enriched asthenospheric mate- rial, involving small amounts of fluids and melt. We have proposed that the emplacement of a shallow asthenosphere would have orig- inated through extension and passive upwelling at the time of basin formation, and explained its preservation through geologic time by invoking lateral asthenospheric flow from a distant source. We have proposed that the hot, buoyant asthenospheric mate- rial under the basin provided a vertical push under the Araripe Basin that helped the tectonic inversion of the basin. Additionally, the presence of this asthenospheric material under the Araripe Basin – and the correspondingly raised geotherm – might have weakened the lithospheric mantle, caused regional compressional stresses to concentrate on the brittle crust, and contribute to basin uplift. The high resistivities flanking the conductive anomaly north and south of the Araripe Basin have been interpreted as thickened lithosphere representing lithospheric material that was eroded from under the basin and attached to the flanks through a roll-down flow process. Shear zones have been mapped as conductive anomalies cross- ing the crust in the Borborema region, suggesting the presence of conductive minerals or graphite, precipitated by fluids flow and shear zone reactivation. To the south of the profile, the Riacho do Pontal fold belt is observed to be flanked by conductive structures, which have been interpreted as relict subduction material, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq): grant no 400743/ 2014-0 CNPq: visiting research fellowship held under the Ciência Sem Fronteiras program. CNPq: process no 304421/2015-4, B01_NBPB_nw.edi B02_NBPB_ne.edi B03_NBPB_sw.edi B04_NBPB_ne.edi B05_NBPB_ne.edi B06_NBPB_ne.edi B07_NBPB_nw.edi B08_NBPB_se.edi B09_NBPB_ne.edi B10_SW.edi NBPB_AR09_se.edi NBPN_NBPB_nw.edi, Peer reviewed