PALEOCLIMATE RECONSTRUCTION OF THE GULF OF AQABA USING FORAMINIFERA AS A PROXY

Regions at the margin of an arid climate zone such as the Gulf of Aqaba are ideal locations to test the magnitude and rate of past environmental change. The purpose of this study is to reconstruct the paleoclimate of the Northern Gulf of Aqaba based on microfossil foraminiferal assemblages from a 4.3-meter long sediment core recovered from the continental shelf. This study implements the newly developed diver-assisted coring technique designed specifically for sandy substratum in shallow (<30 m) water. We collected core MG10H02 from 25 m water depth during a February 2010 coring campaign. Sediment from the core was sampled at a 10-cm interval and sieved at 150 µm. Variations in the bioclastic and siliclastic sediment composition provides evidence of changes in the depositional environment. Bioclastic materials dominate the top and base of the core within depth intervals 0-40 cm and 250-430 cm. Siliclastic sediments compose most of the sediment within the core interval from 40-250 cm. The sediment grain size range is limited to clay and silt throughout the core with a possible fining upward sequence at 380 cm. To date, this study has identified a minimum of 300 foraminifera specimens to the genus level per subsample. The Order Rotaliina, specimens Ammonia, Assilina, Amphistegina, and the Order Miliolida, specimens Lachlanella, Hauerina, and Quinqueloculina, occur most frequently. The relative frequencies of these forams shift from Rotaliina-dominated assemblages in the upper core (<180 cm) to Miliolida-dominated in the lower core section (>180 cm). Preliminary results reveal a foraminifera barren layer at 170 cm. This suggests terrestrial sedimentary deposition on the shelf at this time. A shift from an arid to a humid climate regime marked by a dramatic increase in precipitation and delivery of terrigenous sediment to the shelf is one possible explanation for the massive terrestrial input documented in this core.