Vegetation, climate, and sea level in the past 55,000 years, Hanjiang Delta, southeastern China

Pollen in Quaternary deposits from the subtropical Hanjiang Delta records t hree major phases in the local vegetation and climate history during the la st 55,000 yr: (1) a prevalent cool-to-temperate and humid climate at ca. 24 ,000 C-14 yr B.P. is indicated by abundant pollen of temperate trees includ ing conifers; (2) between 20,000 and 15,000 C-14 Yr B.P., a cold, dry envir onment was associated with low sea level during the last glaciation, leadin g to subaerial exposure, weathering, and interruption of sedimentation, as well as departure from the region of Dacrydium and Sonneratia; (3) a short- term expansion of grassland at ca. 10,300 C-14 yr B.P. reduced the predomin ant Lauraceae-Fagaceae evergreen forest, possibly corresponding to the Youn ger Dryas cooling. The combined data indicate a maximum sea-level rise in t he mid-Holocene (7500-4000 C-14 yr B.P.) and a marine influence in the late Pleistocene at 45,000-20,000 C-14 yr B.P. The Holocene warming, however, d id not bring back moisture-sensitive taxa, indicating high seasonal aridity probably caused by renewed monsoon conditions. (C) 2000 University of Wash ington.