GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 The seismic datasets used for this study are vintage seismic reflection datasets: the MS and the Strakhov-5 surveys. These two surveys consist of regional and deep seismic profiles acquired during the first geophysical exploration phase of the Mediterranean Sea. From 1969 to 1982, the National Institute of Oceanography and Applied Geophysics (OGS) in Trieste (Italy) acquired several multi-channel seismic profiles with the National Research Council ship "Marsili" as part of an Italian scientific program to explore the entire Mediterranean basin (Mediterranean Sea Project, MS; Finetti and Morelli, 1973). All seismic sections have been reprocessed and time-migrated in recent years by the OGS using modern seismic processing techniques. In 1987, GEOMAR (i.e., Helmholtz Center for Ocean Research Kiel), in collaboration with the Russian Academy of Sciences acquired 1700 km of multichannel seismic reflection data over the Cyprus arc system from the Florence Rise to the Syrian coast during the 5th cruise of the research vessel Akademik Nikolay Strakhov. This was the first comprehensive geophysical data acquisition around the Cyrpus arc system and, more generally, in the northern Levant Basin. This dataset includes the stack version and the depth-migrated version of the seismic profiles and also the velocity analysis. Regardless of the reprocessing phase, the resolution for the first 3/7 seconds (TWT) is good, depending on the water depth. However, these seismic sections have a good penetration depth to visualise the entire Cenozoic deposits and deeper structures than other seismic profiles in the study area (Calon et al., 2005; Hall et al., 2005; Maillard et al., 2011). The first phase was dedicated to the seismic interpretation of the time-migrated sections. We interpreted the main seismic packages and faults, as our aim is to build an evolutionary tectonic model of the area that describes the Cenozoic evolution. We use the velocity analysis of the seismic profile together with previous estimates of the velocities of the seismo-stratigraphic packages to create geological sections that match our seismic profiles. The depth profiles are a prerequisite for building an evolutionary model that describes the major tectonostratigraphic phases. RESULTS This study focuses on three transects crossing the main offshore structures (i.e., Florence Rise, Cyprus Arc and Latakia Ridge) from west to east (Fig.2). Figure 2: a) Western transect with detail zoom centered on the trench. b) Central transect with detail zoom centred on the trench. c) Eastern transect with detail zoom centered on the trench. The western transect (MS53) shows how the Herodotus oceanic crust subducting northward beneath the Eurasian plate. The Florence Rise is the leading edge of the system, and the Antalya Basin is its forearc basin. Near the Turkish coast, a buried block appears to act as a backstop for the offshore system, and north of it, some out-of-sequence thrusts have been interpreted. The strain is partitioned between the Florence Rise and the Taurides front (Fig.2a).