Active Tectonics of the North Tunisian Continental Margin

Abstract

A poorly defined boundary between the Nubia and Eurasian plates runs along the Northern Tunisian continental margin. The Tunisia margin is deformed by a slow NW–SE trending convergence resulting in a diffuse deformation zone with scarce and scattered seismicity compared to the seismic activity into the neighboring regions to the east and west along the boundary. The area has been poorly studied and therefore its recent evolution is almost unknown, particularly offshore. Here, we present a structural analysis of the active tectonics in this submarine continental margin. The data used for this analysis are high‐resolution bathymetric maps together with parametric echosounder images which have allowed to obtain a map of active faulting with unprecedented detail. The structural analysis supports a dominantly transpressive to compressive component of faulting, resulting from the current regional NW–SE trending compressive regime between plates. The North‐eastern Domain of the study region contains the highest number of active faults with numerous pockmarks aligned along them. This study shows that the plate boundary across the North Tunisia margin is incipient and poorly developed, which may be due to the fact that deformation is partitioned over a large number of structures, each accommodating a small percentage of convergence, with the exception of the Hayat fault system. The Hayat reverse fault, striking WSW–ENE, is the largest fault system that comparatively may accommodate a greater amount of displacement, and is probably responsible for the uplift of the North‐eastern Domain of the continental margin.

Structure and Tectonic Evolution of the NW Sulu Sea Basin (SE Asia)

“…In Mediterranean subduction-related basins, contraction of young volcanic basement, formed in an extensional context with limited faulting, occurred during an abrupt change from Miocene extension to convergence in lattermost Miocene and Pliocene (Camafort et al, 2020;Gómez de la Peña et al, 2021), and it is currently accumulating most deformation in the region (Gómez de la Peña et al, 2022). Reactivation of pre-existing tectonic features resulted in local inversion and formation of related anticline-syncline folds (Camafort et al, 2022;Giaconia et al, 2015;Zitellini et al, 2020), resembling deformation observed in the NW Sulu Sea (Figure 2, line SO23-01, CDPs 8000-5900; Figure 6, line SO23-16, CDPs 6500-4000).…”