RAPID RISE (~3 MM/Y) OF COASTAL ABU DHABI

Dating of elevated marine deposits on the coastal sabkha of the Emirate of Abu Dhabi, UAE suggests that land surface has risen 80 m in ~25,000 years (~3 mm/y). The age (24,200 through 28,200 yr BP) and elevation that average 5 m above current mean sea level were measured on three zeugen (marine-carbonate capped table-like structures). Sea level at the time of deposition was ~75 m lower than present; thus, the zeugen represent an uplift of nearly 80 m. The carbonate caprock is composed of ooids, gastropods, and mollusks and contains coralline algae and benthic foraminifera. Fossil assemblage, strontium, carbon, and uranium isotope ratios are consistent with a marine origin of the carbonate caprock that unconformably overlie eolian dunes. The contact between the caprock and eolian deposit (43,000 years) is a high-energy irregular erosional surface with over 20 cm of vertical relief in 3 m. Optical stimulation luminescence on eolian quartz grains and calibrated radiocarbon dating of shells were used to determine the ages. Progradation of the Abu Dhabi coastal sabkha into the Arabian Gulf is consistent with uplift in the area. The rapid rise may be directly related to convergence or to isostatic uplift associated with erosion in the Zagros Mountains; data collection from a wider area will help to distinguish between these possibilities. Zeugen are found at approximately the same elevation along the 300-km coastline of the Emirate of Abu Dhabi, thus their rise is unlikely to result from salt diapirs.