The Kinematics of the Dor Disturbance Offshore Israel: The Controls of Pre-MSC Morphology on the Thin Skin Deformation Patterns and Styles

Abstract

Thin-skinned tectonics at passive continental margins plays an important role both in hydrocarbon exploration and as a geohazard. The deformation of salt and overburden manifests as an intricate pattern of faulting, and sub-basins formation. The faulting has implications on shelf stability and may also act as conduits for hydrocarbon migration from pre-salt section. Furthermore, the basins are a potential accommodation space for hydrocarbon reservoirs. The regional displacement of salt and overburden across the Israeli continental margins was discussed by past studies. However, the local 3D complexity of deformation and its directions have not been fully addressed. This seismic interpretation study addresses the kinematics of the Dor Disturbance, a prominent focus of thin-skinned tectonics complexity offshore north central Israel, covering an area of c. 40 km2. To examine the control of the pre-MSC morphology on the thin-skinned deformation, we analyzed the structural elements of both the Dor Disturbance and the base Messinian surface (N). Analysis was done mainly on the southern part of the Disturbance area, covered largely by three 3D seismic datasets and a grid of 2D seismic profiles. More than 500 fault segments were interpreted across the study area using both amplitude sections and coherence slices. Outlines representing the recent activity on the faults were extracted using guiding horizons and manually, and the direction of faulting was interpreted by using a combination of indicative structural and surficial features. Three main classes of faults are found within the study area. These classes delineate three different domains of the Disturbance: (1) Upper slope extensional belt, which is dominated by normal faults that are rooted into a pre-kinematic Pliocene unit; (2) Base of slope extensional belt, which is dominated by normal faults that are rooted into the base Messinian surface N; and (3) Translational domain that is dominated by oblique slip faults, or pure strike slip faults, which are interpreted as dextral faults. The two extensional belts converge to one system at the center of the Disturbance and diverge southwards. The base Messinian N-surface slope is steep and semicircular around the center of the Disturbance, and becomes gentler and wider, forming two to three steps in the southern part of the Disturbance. In general, the N is inclined to the west-northwest except for a c. 6 km belt ~30 km southwest of the Disturbance focus, where the inclination is directed to the south and its intensity is significantly lower. The translational domain defined above is located above this belt. Furthermore, a Ramp Syncline Basin is located to the south of the Disturbance at the Messinian rooted extension domain, with a close association to a pronounced step of the N. An estimation of flow direction was obtained from the dip and dip-azimuth of the N-surface. Our analysis results indicate a match between the faulting directions in the different domains and the estimated flow vectors. Moreover, the maximum thickness of the Plio-Quaternary overburden coincides with a convergence of the flow lines. Therefore, we conclude that the pre-MSC morphology has a key role in setting the deformational patterns of the Dor Disturbance, explaining its complex 3D kinematics.

AAPG Datapages/Search and Discovery Article #90341 ©2019 AAPG Geoscience Technology Workshop, Exploration and Development of Siliciclastic and Carbonate Reservoirs in the Eastern Mediterranean, Tel Aviv, Israel, February 26-27, 2019