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
• Main Authors: Pinheiro, J. M., Schnurle, P., Evain, Mikael, Afilhado, Alexandra, Gallais, F., Klingelhoefer, Frauke, Loureiro, Afonso, Fuck, R., Soares, J., Cupertino, J. A., Viana, Adriano Roessler, Rabineau, Marina, Baltzer, A., Benabdellouahed, M., Dias, Nuno, Moulin, Maryline, Aslani, D., Morvan, L., Maze, J. P., Pierre, D., Roudaut-Pitel, M., Rio, I., Alves, D., Barros, P., Biari, Youssef, Corela, Carlos, 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: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2018
• Subjects: South Atlantic ocean; NE Brazil; Sergipe-Alagoas basin; Passive margins; Wide-angle refraction seismics; Crustal structure; Tectonic inheritance; South Atlantic Ocean
• Online Access: http://hdl.handle.net/10400.21/9342; https://doi.org/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 similar to 100 km wide necking zone is imaged where the continental crust thins from similar to 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 similar to 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. info:eu-repo/semantics/publishedVersion