Postglacial flooding and Holocene climate shifts in the Persian Gulf

Postglacial flooding of the Persian Gulf (PG) was important in shaping human history and driving landscape changes in the region. However, there is a paucity of data regarding the postglacial transgression. The position of the PG at the edge of major synoptic systems of the Indian Ocean Summer Monsoon (IOSM) and Mid-latitude Westerlies (MLW) makes the environment particularly sensitive to Holocene climate shifts. To investigate the timing of the flooding and to detect the impacts of significant climate shifts on the regional environment during the Holocene, a multiproxy study was conducted on three short sediment cores from two deep sites in the PG. Sedimentological, palynological and geochemical analyses were performed on the cores. The results show that inundation of the western part of the PG that started from ca. 11.5 ka bp continued with successive prominent phases of transgression centered on 10.4 and 9.2 ka cal  bp, and definitive marine conditions were established around 8.8 ka cal  bp. The IOSM was the dominant system in the region until about 9 to ~6.3 ka cal  bp. After that time, the intensity of the IOSM declined, as MLW dominated the region after ~6.3 ka cal  bp. These climatic shifts induced significant changes in regional vegetation and hydrology, and possibly triggered socio-cultural transformations.