Structural analogy between the “piano key faults” of deep-water Lebanon and the extensional faults of the Canyonlands grabens, Utah, United States

Abstract

The Levant Basin is a deep-water basin in the eastern Mediterranean region. A large part of the basin contains a characteristic set of closely spaced normal faults, informally called the “piano key faults.” These normal faults trending NW-SE have a fairly high-frequency map-view spacing of approximately 3–4 km on average and tens to hundreds of meters of interpreted throw. A large part of the pre-Messinian sedimentary strata is faulted, including the entire Miocene-to-Oligocene sequence. At depth, all the faults consistently die out at the same intra-Eocene detachment level. This stratigraphic level is interpreted to have a regionally developed shale sequence acting as the basal detachment surface for the piano key faults. The amount of throw on the individual faults appears to decrease toward the basin margin and the faults do not extend into the adjacent basins of the broader eastern Mediterranean area.

Petroleum Systems of Lebanon: An Update and Review

“…The distal Levant Basin The consistent detachment of normal faults on the Eocene unconformity horizon (Fig. 12), together with the chaotic seismic facies and weak amplitudes observed in the Paleocene/Eocene, suggest that the latter is probably composed of shales (Kosi et al, 2012) and other highly overpressured deposits . Therefore, it is likely that the Paleocene/Eocene package forms an impermeable unit which could seal the underlying reservoirs and prevent vertical hydrocarbon migration in the distal Levant Basin.…”

“…At depth, all the faults consistently die out at the same intra-Eocene detachment level, which has been interpreted as a regionally developed shale ( Fig. 12) Hawie et al, 2013;Kosi et al, 2012). As no NE-SW extension is documented to have occurred in the basin during the Oligo-Miocene, a solely tectonic origin for their formation or an origin related to the Messinian Salinity Crisis has been refuted (Ghalayini et al, 2016).…”

Inversion tectonics: a brief petroleum industry perspective

“…11b) the Tamar anticline has a slightly asymmetric closure trending SW-NE. The prominent NW-SE-striking "piano-key" faults (Kosi et al, 2012) crosscutting the anticline are quite typical for the entire deepwater Levant Basin. These faults are not sealing in nature as the gas-water contact (GWC) is at the same depth of 4797 m (Fig.…”

Origin and kinematics of a basin-scale, non-polygonal, layer-bound normal fault system in the Levant Basin, eastern Mediterranean

“…One particularly striking example of a basin-scale (~70,000 km 2 ), non-polygonal layer-bound fault system, for which the diagenetic model has previously been proposed, is the "piano-key" fault system of the Levant Basin, eastern Mediterranean (Kosi et al, 2012;Ghalayini et al, 2017). Comprised of NW-striking, mostly non-polygonal, linear (i.e., one single dominant orientation) faults, this system covers the entire Levant Basin, displacing the >2 km thick Oligocene-Miocene strata (Ghalayini et al, 2017).…”

“…Comprised of NW-striking, mostly non-polygonal, linear (i.e., one single dominant orientation) faults, this system covers the entire Levant Basin, displacing the >2 km thick Oligocene-Miocene strata (Ghalayini et al, 2017). By integrating seismic attribute analysis and throw measurements along the faults surface, the spatial and temporal evolution of the fault system has been analysed in the Northern Levant Basin (Figure 1) (Kosi et al, 2012;Hawie et al, 2013;Ghalayini et al, 2017;Ghalayini and Eid, 2020). On the basis of the faults layerbound geometry, a small portion of polygonally-shaped faults in the system, and the lack of known extension events at times of presumed fault nucleation, Ghalayini et al (2017) associated the piano-key faults with the same dewatering, diagenetic mechanism often inferred to drive polygonal fault nucleation and growth.…”