Architecture of Eastern Mediterranean sea rifted margins: observations and uncertainties on their Mesozoic evolution

• Published in: International journal of earth sciences : Geologische Rundschau 2023-03, Vol.112 (2), p.459-488
• Main Authors: Nirrengarten, M., Mohn, G., Sapin, F., Nielsen, C., McCarthy, A., Tugend, J.
• Format: Article
• Language: English
• Subjects: Age composition; Boreholes; Carbonates; Continental crust; Cretaceous; Domains; Earth and Environmental Science; Earth Sciences; Evolution; Geochemistry; Geology; Geophysics/Geodesy; Gravity anomalies; Mesozoic; Mineral Resources; Oceanic crust; Offshore; Original Paper; Paleoceanography; Passive margins; Permian; Platforms (geology); Rifting; Sciences of the Universe; Sedimentology; Segments; Seismic data; Seismological data; Stratigraphy; Structural Geology; Subduction; Subduction (geology); Subduction zones; Tectonics; Triassic; Uncertainty
• ISSN: 1437-3254; 1437-3262
• DOI: 10.1007/s00531-022-02263-5

The geodynamic evolution of the East Mediterranean Sea (EMS) in the Mesozoic remains a “Gordian knot” tying together the Atlantic and Tethys oceanic systems. A key to unravel its complex evolution resides in determining the structure and formation age of its passive margins. Here, we investigate the Mesozoic architecture of different segments of the southern passive margin of the EMS using 2D and 3D seismic data combined with stratigraphic observations and gravity anomaly maps. Based on these offshore datasets, a new structural rift domain map of the eastern EMS is proposed showing the distribution of different crustal domains. Regional cross sections from the Western Desert to the northern Levant passive margins systematically show a sharp crustal neck of the EMS passive margins passing laterally in less than 30 km from moderately thinned continental crust (20–25 km thick) overlain by post-rift carbonate platform to distal deep basin (top basement > 8 s TWT). This sharp crustal thinning observed on both the southern and eastern margins of the EMS hampers the unambiguous identification of transform passive margin segments from orthogonal ones. The age of rifting and spreading of the different EMS basins are only partially constrained by boreholes and seismic correlation. To reduce uncertainties, we analyze and integrate the stratigraphic rift record from onshore former conjugate margins, which are now integrated in the Alps, Balkanides, Hellenides and Taurides belts on the northern side of the EMS. With this offshore/onshore approach, we identified the spatial and temporal evolution of rifting and spreading activity around EMS, highlighting poly-phased and poly-directional events from the Permian to the Cretaceous. We show that two competing geodynamic engines controlled extensional processes in the EMS: the opening of the Central Atlantic since the Late Triassic to the southwest and the evolution of multiple subduction zones in the Tethys domain to the northeast.