Middle and Upper Jurassic stratigraphy and sedimentary evolution of Lebanon (Levantine margin): palaeoenvironmental and geodynamic implications

Abstract

The Arabian, African and Eurasian plates interact in the Levantine region. Despite numerous studies of the region, many geological issues relating to Mesozoic times remain unresolved. The Lebanon passive margin is a key area for understanding Neo-Tethyan sedimentary history during this period. The Jurassic succession in Lebanon is well exposed and thick (more than 1000 m). It is more or less complete and relatively undeformed. With a few recent exceptions most studies of the area were made in the 1950s and so the sedimentary evolution of the Jurassic is only partly understood.This study provides (1) a new sedimentary and sequence stratigraphic framework, and (2) a new biostratigraphic framework based on benthic foraminifera and calcareous algae. Palaeoenvironmental and geodynamic conclusions are inferred.Jurassic outcrops occur in both the Mount Lebanon and the Anti-Lebanon areas. Here, they were studied essentially in Mount Lebanon. The Jurassic succession can be divided into three parts: (1) the lower part (Kesrouane Formation) is a thick succession of marine limestones or dolomites; (2) the middle part (Bhannes Formation) consists mainly of basaltic eruptive rocks associated with pyroclastic strata; (3) the upper part (Bikfaya Formation) is a succession of marine limestones.During the Bathonian, Callovian, Oxfordian and parts of the Kimmeridgian, a large epicontinental shelf, with very shallow marine environments, extended across Lebanon (Kesrouane Formation). The period was characterized by a stable platform morphology. It was a tectonically quiet period, although intense subsidence allowed the accumulation of a thick sediment package. During the Kimmeridgian, the carbonate platform regime that had dominated Lebanon during the Middle Jurassic came to an abrupt end, as evidenced by a regional unconformity, a regression and block faulting. This rifting phase is associated with a volcanic event (Bhannes Formation) that is recognized from northern to southern Lebanon. During the Lower Jurassic (Kimmeridgian p.p. to Tithonian p.p.) shallow marine carbonate shelf deposits are observed again (Bikfaya Formation), indicating a marine transgression. This last formation exhibits rapid lateral thickness variations, because of active block faulting and erosion, and is overlain by continental sandstones of the basal Cretaceous.

Geological Interpretation of 2d Seismic Reflection Profiles Onshore Lebanon: Implications for Petroleum Exploration

“…The Top-Jurassic (S2) represents a major sequence boundary corresponding to the base of the Chouf sandstone Formation observed onshore. Aggrading Jurassic and Cretaceous platform carbonates have been described onshore Lebanon and Israel (Collin et al, 2010;Gardosh et al, 2010;Hawie et al, 2013) and extend off the Levant margin, with hemipelagic deposits in deep-basinal areas (e.g. Gardosh et al, (Fig.6).…”

Petroleum Systems of Lebanon: An Update and Review

“…A number of ENE-WSW, currently active, dextral strike-slip faults occur along Mount Lebanon (Gedeon, 1999) and extend into the Levant margin offshore (Ghalayini et al, 2014). These faults most likely developed during the Mesozoic as normal faults during the break-up of Pangea and were subsequently reactivated during Neogene compression (Collin et al, 2010;Ghalayini et al 2014). Similar faults are also found in the Palmyra Basin to the east.…”

Key geological characteristics of the Saida-Tyr Platform along the eastern margin of the Levant Basin, offshore Lebanon: implications for hydrocarbon exploration

“…1), a regional sinistral strike-slip fault system extending from the Gulf of Aqaba (Red Sea) to the Taurus mountains in Turkey, forming the Arabia-Africa plate boundary (Freund et al, 1970;Dubertret, 1972). Strike-slip motion across the LFS is believed to have occurred initially in middle Miocene times in the southern Dead Sea segment (Quennell, 1958;Freund et al, 1970;Garfunkel, 1998), in the Late Miocene in the central Lebanese segment (Homberg et al, 2010), and in the Pliocene in the northern Ghab segment (Al Abdalla et al, 2010;Searle et al, 2010). Displacement on the LFS in Lebanon was in general transpressional during the Late Miocene resulting in a restraining bend and causing uplift of pre-existing structures (Butler et al, 1998;Gomez et al, 2006).…”

“…A number of ENE-WSW, currently active, dextral strike-slip faults occur along Mount Lebanon (Gedeon, 1999) and extend into the Levant margin offshore (Ghalayini et al, 2014). These faults developed most likely during the Early Mesozoic as normal faults during the Tethyan rifting, and were subsequently reactivated from the Late Cretaceous to the Neogene compression (Collin et al, 2010;Ghalayini et al, 2014). They are observed to crosscut N-E trending folds both offshore and onshore by about 1 or 2 km, right-laterally (Ghalayini et al, 2017b).…”