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., Schnürle, P., Evain, M., Afilhado, A., Gallais, F., Klingelhoefer, F., Loureiro, A., Fuck, R., Soares, J., Cupertino, A., Viana, A., Rabineau, Marina, Baltzer, A., Benabdellouahed, M., Dias, N., Moulin, M., Aslanian, D., Morvan, L., Mazé, P., Pierre, D., Roudaut-Pitel, M., Rio, I., Alves, D., Barros Junior, P., Biari, Y., Corela, C., Crozon, J., Duarte, J., Ducatel, C., Falcão, C., Fernagu, P., Le Piver, D., Mokeddem, Z., Pelleau, P., Rigoti, C., Roest, W., Roudaut, M.
• Other Authors: Unité Géosciences Marines (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Instituto Superior de Engenharia de Lisboa (ISEL), Instituto Dom Luiz, Universidade de Lisboa = University of Lisbon = Université de Lisbonne (ULISBOA), Petrobras Rio de Janeiro, Laboratoire Géosciences Océan (LGO), Université de Bretagne Sud (UBS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Littoral, Environnement, Télédétection, Géomatique UMR 6554 (LETG), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Université d'Angers (UA)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2018
• Subjects: South Atlantic Ocean; NE Brazil; Sergipe-Alagoas Basin; Passive Margins; Wide-angle refraction seismics; Crustal structure; Tectonic Inheritance; [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [SDU.STU.TE]Sciences of the Universe [physics]/Earth Sciences/Tectonics; [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology
• Online Access: https://hal.univ-brest.fr/hal-01958592; https://hal.univ-brest.fr/hal-01958592/document; https://hal.univ-brest.fr/hal-01958592/file/59315.pdf; https://doi.org/10.1016/j.jsames.2018.09.015

International audience 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.