Lithospheric structuration onshore-offshore of the Sergipe-Alagoas passive margin, NE Brazil, based on wide-angle seismic data

• Published in: Journal of South American earth sciences Vol. 88; pp. 649 - 672
• Main Authors: Pinheiro, J.M., Schnurle, P., Evain, M., Afilhado, A., Gallais, F., Klingelhoefer, F., Loureiro, A., Fuck, R., Soares, J., Cupertino, J.A., Viana, A., Rabineau, M., Baltzer, A., Benabdellouahed, M., Dias, N., Moulin, M., Aslanian, D., Morvan, L., Mazé, J.P., Pierre, D., Roudaut-Pitel, M., Rio, I., Alves, D., Barros Junior, P., Biari, Y., Corela, C., Crozon, J., Duarte, J.L., Ducatel, C., Falcão, C., Fernagu, P., Le Piver, D., Mokeddem, Z., Pelleau, P., Rigoti, C., Roest, W., Roudaut, M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2018; Elsevier
• Subjects: Crustal structure; Earth Sciences; NE Brazil; Oceanography; Paleontology; Passive margins; Sciences of the Universe; Sergipe-Alagoas basin; South Atlantic ocean; Tectonic inheritance; Tectonics; Volcanology; Wide-angle refraction seismics; NE Brazil; Sergipe-Alagoas basin; Passive margins; South Atlantic ocean; Wide-angle refraction seismics; Crustal structure; Tectonic inheritance; Passive Margins; South Atlantic Ocean; Tectonic Inheritance; Sergipe-Alagoas Basin
• ISSN: 0895-9811; 1873-0647
• DOI: 10.1016/j.jsames.2018.09.015

The structure and nature of the crust underlying the Camamu-Almada-Jequitinhonha-Sergipe-Alagoas basins System, in the NE Brazilian margin, were investigated based on the interpretation of 12 wide-angle seismic profiles acquired during the SALSA (Sergipe ALagoas Seismic Acquisition) experiment in 2014. In this work, we present two 220-km-long NW-SE combined wide-angle and reflection seismic profiles, SL 01 and SL 02, that have been acquired using 15 ocean-bottom-seismometers along each profile, offshore the southern part of the Sergipe Alagoas Basin (SAB), north of the Vaza-Barris Transfer zone. The SL 02 has a 150-km long inland continuation with 20 land-seismic-stations until the Sergipano Fold Belt (SFB). Wide-angle seismic forward modeling allows us to precisely divide the crust in three domains: beneath the continental shelf, a ∼100 km wide necking zone is imaged where the continental crust thins from ∼35 km on the Unthinned Continental Domain, which displays a three-layered crust structure, to less than 8 km on the Oceanic Crust Domain. In the necking zone, the upper and the middle layers thin dramatically and almost disappear, while the Moho discontinuity shows clear PmPs. The Continental-Oceanic Crust Boundary (COB) is located at ∼80 km from the coastline and is marked by intracrustal seismic reflectors and changes in the seismic velocity, showing a sharp transition. On profile SL02, the oceanic crust is perturbed by a volcanic edifice together with an anomalous velocity zone underneath the area. •Sergipe Alagoas Basin passive margin modeling.•Wide-angle refraction seismic integrated with Multi-Channel reflection seismic data.•Location of the Continental- Oceanic crust boundary.•Lithospheric structuration and segmentation of Brazil's margin in Central Atlantic.