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

Abstract

Abstract. The Gulf of Aqaba (Elat) is a developing rift at the southern end of the Dead Sea Transform system. Studying fossil shorelines (coral reef terraces and beach rocks) we obtain constraints on the evolution of the gulf's coastal margin. 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 accumulation 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 consider the regional Holocene climate and Holocene vertical displacements in the gulf, and infer that the eastward propagation of the shoreline reflects a delayed response to tectonic changes in coastal bathymetry or the result of climatic events.

Large earthquakes kill coral reefs at the north‐west Gulf of Aqaba

“…Large cobbles are common next to the buried reef at the lower part of the ∼4‐m‐thick section, and are rare towards the top that is indistinguishable from sediments of the active beaches in the vicinity. The clastic sequence contains a beachrock layer, < 1 m thick, that was indurated at the intertidal elevation (Shaked et al ., 2002).…”

“…Following the earthquake that buried the MLR, sediments transported by waves pushed the shoreline seaward by 100 m (Shaked et al ., 2002). A new state of coastal equilibrium was reached and a new reef started to grow along the shoreline.…”

Diagenetic effects on the distribution of uranium in live and Holocene corals from the Gulf of Aqaba

“…We examined the rejuvenation effect on two fossil corals from the NRR: The first coral from a submarine terrace, 4 m below msl (Shaked et al, 2002), containing less than 5% secondary aragonite and yielded U-Th age of 2500 Ϯ 40 yr; The second coral collected from a buried reef beneath the Marine Laboratory terrace, contained less than 10% secondary aragonite and yielded U-Th age of 4950 Ϯ 90 yr. The U-Th ages of both corals were similar to the radiocarbon dates suggesting negligible rejuvenation effect.…”

Patterns of genetic variation of a Lessepsian parasite

“…The shallow phylogenetic structure of haplotypes indicates a recent history of divergence and demographic expansion within the original Red Sea population, probably linked to the end (about 10000 ybp) of strong environmental variations that occurred during the last glacial phases when the Straits of Bab Al Mandab were closed and salinity increased throughout the Red Sea (Shaked et al 2002). The negative values of Tajima's D in all Red Sea populations and those from the Gulf of Aqaba were significant, while the high values of H compared to estimates of p support the hypothesis of recent demographic expansion.…”