MIS 3 Transgression Record and Pattern in the Shenhu Bay, West Coast of the Taiwan Strait

Through AMS-14C and optically stimulated luminescence (OSL) dating, and analysis of microfossils, grain size, and element geochemistry from borehole samples in the Shenhu Bay on western coast of the Taiwan Strait, combined with global paleo-climate and sea level change records, this study reveals two marine transgression events in the Shenhu Bay which happened in Marine Isotope Stage 3 (MIS 3) and the Holocene. The MIS 3 transgression, corresponding to the previously named "Fuzhou Transgression" is characterized by extensive oyster reefs development. And before the Holocene transgression, ancient forests grew in present beach area of the Shenhu Bay, and subsequent transgression deposits preserved ancient trees. The research suggests pattern of "restricted channel incursion" in uplift region, which is that the MIS 3 transgression involved seawater intrusion through ancient incised valleys or low-lying channels formed in past glacial low sea levels period, distinct from conventional understanding of transgression for coastline parallelly advancing toward coast when sea level rises.