Seismic stratigraphy and deformational styles of the offshore Cyrenaica (Libya) and bordering Mediterranean Ridge

Yem L. Mbida (1, 2) , L. Camera (1) , J. Mascle (1) , A. Ribodetti (1)

1 GEOAZUR 6526 - Géoazur
2 Applied Geology Laboratory UYI

Off northwest Libya the Cyrenaica foreland basin domain and its Pan-African continental crust, which constitute the African promontory, are overthrusted by the Mediterranean Ridge Complex. The thrust belt contact and its seismic stratigraphy have been analysed using pre-stack depth-migrated multichannel seismic (MCS) lines recorded during the MEDISIS survey (2002). The geometry and sedimentary distribution analysis through the wedge-top depocentres allow reconstruction of schematic cross-sections of the tectono-sedimentary wedge that includes two major thrust sequences separated by an apparently poorly deformed transition zone. Based on time-space variation of several piggyback basins, we propose that these thrust sequences relate to distinct phases of shortening. (1) A first event, which probably occurred just prior to the Messinian crisis in latest Miocene (Tortonian times?) and (2) A second event, that has finally led to the present-day overthrusting of the Mediterranean Ridge over the Libyan continental slope.

Domaines: Sciences de la Terre

Yem L. Mbida, L. Camera, J. Mascle, A. Ribodetti. Seismic stratigraphy and deformational styles of the offshore Cyrenaica (Libya) and bordering Mediterranean Ridge. Geophysical Journal International, 2011, 185 (1), pp.65-77. ⟨10.1111/j.1365-246X.2011.04928.x⟩. ⟨hal-00585749⟩