Seminar Details

The history of the last interglacial in the Gulf of Aqaba




Prof. Moti Stein - Geological Survey of Israel


The elevated fossil reef terraces along the north-east coast of the Gulf of Aqaba (GOA) provide information on the history of tectonic uplift, sea-level changes and on the hydrological regime in the gulf vicinity during the last interglacial period. GOA is characterized by fringing reefs with reef flats, representing sea levels at during periods of corals’ growth. Detailed mapping of the reef terraces (Terraces R1, R2, R3) at three sites south to the city of Aqaba allows their characterization on basis of morphology and reef-facies (MSc thesis of Neta Bar). The terraces comprise fringing reefs, some with clear reef structure that includes a reef flat and a shallow back lagoon. Most of the corals in the terraces were recrystallized to calcite indicating extensive interaction with freshwater from coastal aquifer that existed along the shores of the GOA. The ages of recrystallization of the corals from aragonite to calcite and their initial formation ages were determined by U-Th dating method applying the relevant set of equations (MSc thesis of Maayan Yehudai). The wide and developed structure of Terrace R2 was formed during the stable sea level period of MIS5e between ~128 and ~121 ka and the corals were recrystallized to calcite at 103±5 ka. Terrace R1 was formed during a short stillstand at ~ 117 ka. Terrace R3 was formed at ~132-134 ka upon the early sea level rise leading to MIS5e, and its corals were recrystallized to calcite at 128±10 ka. The elevation and ages of the reefs flats indicate an average uplift rate for all sites of 0.11±0.07 m/ka. This relatively low uplift rate enables GOA terraces to reveal the details of MIS5e sea level history. The uplift rate is significantly lower than in other site where the last interglacial sea-level history was studied, e.g. Papua New Guinea and Barbados but still higher than the Bahamas Thus, the details of the last interglacial MIS5e sea level history are not masked. Moreover, the corals provide valuable information on ages of freshwater activity in the currently hyperarid GOA.

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