The Oligo-Miocene deepwater system of the Levant Basin

- 64 -The existence of channel fill deposits in the confined upstream part of the Afiq and Ashdod(Netanya tributary) canyons may suggests further transport to the unconfined setting within thebasin. Support for this transport is found at the western part of the Afiq Canyon. In this area a highamplitudeevent appears on a time slice taken from the 3D survey E as an elongated feature orientedin a NW-SE direction that may be interpreted as channel fill near the outlet of the canyon (Fig. 37).Continental clastic sediments of the Hazeva Group and Hordos Formation continued to accumulatein proximal inland areas during Late Miocene times (Figs. 3 and 38). This indicates the existence ofan extensive source for siliciclastics. Sands could have been remobilized and transported from theshelf area basinward through the entire upper Miocene canyon system.Due to the lack of information on Miocene and older sediments in the Qishon Graben in northernIsrael, except for the Canusa-9 borehole and a few wells that barely penetrated the Messiniangypsum, no statement can be made as to the age and geometry of any pre-Messinian incisions orconfined deposition in the Qishon Graben. The Miocene reefal carbonates below the Messinianevaporites in the Canusa-9 borehole have the characteristics of carbonate platform sedimentation,unlike transported carbonate debris found in channels. It may therefore indicate the existing ofwidely spread Miocene carbonate platform which was later largely removed leaving sparse relictslike the platform carbonates in the Canusa-9 borehole. The seismic data do not provide unequivocalinformation for any pre-base-Messinian incision event. It is therefore suggested that the QishonGraben was not formed prior to Messinian and not later than Early Pliocene.6.4 The Latest Miocene (post-evaporite) successionSubstantial subaerial incision and denudation of the circum Mediterranean took place during thelatest Messinian, following the drawdown of the Mediterranean Sea by some 800 m due to itspartial desiccation (Hsu et al., 1978; Delrieu et al., 1993; Druckman et al., 1995). The reducedevaporitic section, and the significantly thicker Pliocene section overlying it (Figs. 21 and 24c),indicate the removal of part of the evaporites due to a ~ 800 m fall of the Messinian sea level(Druckman et al., 1995; Cartwright and Jackson, 2007) and signifies the post-evaporite incisionevent. This event is better pronounced in the Afiq Canyon, where the evaporites are overlain by asuccession of 90 m of lacustrine clastic sediment, reflecting the Lago Mare circum Mediterraneanevent.