Continental slope processes off northern Israel and southernmost Lebanon and their relation to onshore tectonics

Abstract

The continental terrace of Israel and Lebanon consists of a 1–2 km thick Pliocene-Quaternary sediment wedge that narrows, steepens and deepens from south to north. The continental terrace is the product of (1) Nile-derived sediment accumulation, whose bulk and rate of deposition decrease along the active Levant continental margin with increasing distance from the Nile mouths, and (2) of the vertical tectonic uplift of Israel and Lebanon versus the subsidence of the adjacent submarine Levantine Basin which increases to the north. Collapse of the entire seaward-facing part of the continental terrace off northern Israel, caused by large-scale halokinetic rotational slumping, has further accentuated its steep and narrow wedge form in the study area. Intensive mass-wasting and canyon cutting over the steep continental slope have shaped its present furrowed morphology. Canyon incision is fault controlled, the faults being submarine extensions of the continental fault system effected by drag of the Sinai sub-plate along the Dead Sea-Jordan-Beqa'a transform that has controlled the tectonics and the structure of Israel and Lebanon since the Late Miocene. The canyon heads at the continental shelf lie opposite the mouths of the continental rivers. Canyon cutting processes are not, however, connected to fluvial erosion of the emergent continental shelf during the Last Glacial lowered sea-level stand. Canyon incision started on the continental slope and advanced downslope and upslope toward the shelf. Embryonic slope valleys, canyons confined to the continental slope, a canyon in the process of breaching the shelf break and mature canyons that indent the continental shelf to nearshore distances were mapped and are described.