Pollen spore assemblages and induced palaeoenvironmental changes in the western Bohai Sea since Late Pleistocene

The comprehensive study of the upper 55.34m of core TJC-1 taken from the western Bohai area on sediment lithology, multi-method dating and high resolution spore-pollen data suggests that the changes in pollen assemblage since late Pleistocene are resulted from the joint effects of vegetation, climate and sea-level changes. Conifers, broad-leaved trees and herbs show a regular and cyclic pattern of variation, which indicates a frequent alternation of warm-wet and cold(cool) dry climatic conditions, in addition to significant sea level fluctuation. During the periods of MIS5e, MIS5c, MIS5a, MIS3 and MIS1 (early-middle Holocene), mixed coniferous or deciduous broad-leaved forest were developed in the surrounding upland, and lacustrine-halobiotic grass prevailed on the coastal lowland in warm-wet conditions, indicating a coastal or shallow sea environment. There is a thin layer of LGM deposits in MIS2. During the periods of MIS5d, MIS5b, MIS4, and MIS2, conifers prevailed on the upland, and Artemisia-Chenopodiaceae dominated herbs in the lowland area under a cold(cool)-dry climate and low sea level.