When did Goliath collapse? Dating the recent events of a major submarine slide complex, Southeastern Mediterranean margin

Abstract

Unraveling the failure history of submarine slides and delineating its environmental controls are crucial for practical hazard assessments, but are commonly challenging and costly. Here we address this challenge by investigating the Goliath slide complex, one of the largest documented slide scars on the ~200 km long continental slope offshore Israel. Geophysical evidence suggest that the Goliath complex is a relatively young feature. However, despite its proximity to submarine infrastructure and to one of the most populated coastal areas in the Mediterranean, its recent temporal development was never determined.Based on a detailed analysis of sub-meter resolution multi-channel seismic profiles, four sediment cores were retrieved from the northern head scarp and toe domains of the Goliath slide complex. Selective sedimentological and chronological analyses were carried out following a detailed computed tomography analysis of the cores. The results reveal two generations of deposits on the northern head scarp of Goliath, separated by a detachment surface. Two 14C ages of 7.46 ± 0.13 cal ka BP (core PHS-1) and 7.38 ± 0.16 cal ka BP (core PHS-5) were obtained for the sediments immediately overlying this surface, implying that the Goliath northern head scarp was formed, at least in part, during a substantial ~7.4 cal ka BP event. A ~3.7 kyrs hiatus within the late Holocene sedimentary sequence of core PHS-5 may suggest an additional, more recent and presumably smaller, slide event that occurred at ~2.4 ka BP. The sedimentary succession from Goliath's toe domain (core PTL-3), located ~32 km downslope from the head scarp, show an upper 1.2 m long continuous undisturbed sequence dated to the last ~14 ka BP and including sapropel S1 deposits. This sequence overlies three disturbed units, interpreted as mass transport deposits (MTDs) containing various deformation features, large-scale burrows, sharp contacts and fold structures. A 14C age dates the base of the hemipelagic sequence to 13.91 ± 0.23 cal ka BP, representing the minimum age of the slide event that deposited this MTD. Ages within the MTD units are substantially older (18.21 ± 0.27 to 28.66 ± 0.33 cal ka BP) than in the overlying sequence and an age-inversion within the MTDs supports their interpretation as transported sediments.The timing of the prominent slide events in the Goliath complex corresponds with the late stages of meltwater pulses 1A (~14.6–13.7 ka BP) and 1C (~8.2–7.5 ka BP), periods of accelerated sea level rise and probably increased sediments supply. Our results suggest that climate-driven factors likely contributed significantly to slope instability in this area, while earthquakes on the Dead Sea Transform may have been the triggering factor for the Goliath Slide events.