Late Holocene shorelines at the Gulf of Aqaba: migrating shorelines under conditions of tectonic and sea level stability

Abstract

The Gulf of Aqaba (Elat) is a developing rift at the southern end of the Dead Sea Transform system. Study- ing fossil shorelines (coral reef terraces and beach rocks) we obtain constraints on the evolution of the gulf's coastal mar- gin. Fossil reefs at the gulf indicate that during the past 6000 years sea level was relatively stable, and regional vertical tectonic movements were negligible. Nevertheless, south of Elat (NW corner of the gulf) we find that the shoreline has migrated seaward by more than 100 m, through accumula- tion of coarse clastic sediments. In the absence of a fluvial feeder at the location of the migrating shoreline, we suggest that long-shore processes transported the sediment. Our observations include sedimentary structures from two trenches dug in beach sediments, buried and emerged fossil reefs, and the local submarine slope morphology. We con- sider the regional Holocene climate and Holocene vertical displacements in the gulf, and infer that the eastward propa- gation of the shoreline reflects a delayed response to tectonic changes in coastal bathymetry or the result of climatic events.