Impact of Cenozoic strike-slip tectonics on the evolution of the northern Levant Basin (offshore Lebanon)

Abstract

Sedimentary basins adjacent to plate boundaries contain key tectonic and stratigraphic elements to understand how stress is transmitted through plates. The Levant Basin is a place of choice to study such elements because it flanks the Levant Fracture System and the Africa/Anatolia boundary. This paper uses new high-quality 3-D seismic reflection data to unravel the tectonic evolution of the margin of this basin during the Cenozoic, the period corresponding to the formation of the Levant Fracture System, part of the Africa/Arabia plate boundary. Four major groups of structures are identified in the interpreted Cenozoic units: NW-SE striking normal faults, NNE-SSW striking thrust-faults, ENE-WSW striking dextral strike-slip faults, and NNE trending anticlines. We demonstrate that all structures, apart of the NW-SE striking normal faults, are inherited from Mesozoic faults. Their reactivation and associated folding started during the late Miocene prior to the Messinian salinity crisis due to a NW-SE compressional stress field. No clear evidence of shortening at present-day offshore Lebanon and no large NNE-SSW strike-slip faults parallel to the restraining bend are found indicating that the Levant Fracture System is mainly contained onshore at present day. The intermittent activity of the interpreted structures correlates with the two stages of Levant Fracture System movement during late Miocene and Pliocene. This paper provides a good example of the impact of the evolution of plate boundaries on adjacent basins and indicates that any changes in the stress field, as controlled by the plate boundary, will affect immediately the preexisting structures in adjacent basins.

Integrated 3D forward stratigraphic and petroleum system modeling of the Levant Basin, Eastern Mediterranean

“…Solely permeabilities and specific surface areas were adjusted for cross‐cutting lithologies which enables possible vertical fluid migration pathways at timing of presumed fault activity. According to Ghalayini et al (), most faults were active during or after deposition of Miocene sediments, which supports a simplistic representation in numerical models that neglects fault‐related deformation. However, the study could benefit from the use of new modeling tools which can account for more robust fault behavior (Woillez, Souque, Rudkiewicz, Willien, & Cornu, ).…”

“…Fluid flow calculations are based on a fully implicit generalised Darcy flow migration scheme which accounts for the main mechanisms driving fluid flow in petroleum system: (a) buoyancy; (b) pressure gradients; and (c) capillary forces. Since faults can play an important role in the Levant Basin, a care has been given to account for some representative fault systems compiled and digitalised after Ghalayini et al () (Table ). We utilised a simplified approach for an initial approximation of fault related fluid migration pattern.…”

“…Geochemical parameters were integrated from previous source rock studies (Bou Daher et al, 2016. Further fluid migration scenarios were created considering selected fault systems (Ghalayini et al, 2014;Ghalayini, Homberg, Daniel, & Nader, 2017).…”

“…In general, post-Jurassic source rocks are thermally immature in the onshore, but are likely to have reached higher thermal maturity in the offshore owing to greater burial depth and related higher temperatures. In the simulation, only the deepest Permian and T A B L E 4 Summary of fault system properties according to Ghalayini et al (2014) 90% in the majority of the deep offshore, especially for Cenomanian source rocks leading to the conclusion that oil generation is terminated. In addition to numerical modeling of source rock maturation and petroleum generation (see Bou Daher et al, 2016), this study assesses possible migration trends and accumulation of hydrocarbon fluids.…”

Petroleum Systems of Lebanon: An Update and Review

“…An improved understanding of the geology of the Levant region has been acquired from interpretations of this data-set by academic and industrial research partners. The results of these studies include: (i) a new stratigraphic model for the Levant Basin based on seismic data, extensive fieldwork, and forward modelling (Hawie et al, 2013(Hawie et al, , 2014(Hawie et al, , 2015; (ii) a more detailed structural framework for the Levant Basin and margin based on new 3D seismic data interpretation and analogue modelling (Ghalayini et al, 2014(Ghalayini et al, , 2016(Ghalayini et al, , 2017; (iii) a thorough geochemical assessment of source rock potential supported by extensive sampling onshore and regional basin modelling, providing an updated evaluation of the hydrocarbon potential of Lebanon (Bou Daher et al, 2014; and (iv) an improved model of the crustal structure of the Levant Basin confirmed by deep seismic and gravity modelling (Inati et al, 2016).…”