In order to study vegetation evolution and en- vironmental change since the Last Glacial Maximum (LGM), a total of 180 pollen samples with an average time resolution of 150 years were analyzed on the top parts(0–31 m, 0–27 kaBP)of deep sea sediments from ODP Site 1144 (20°3.18′N, 1170°25.14′E), northeastern SCS. The character- istic fea- tures of pollen diagram include that pine dominates in the interglacial, and herb pollen dominates with a good deal of tropical-subtropical pollen in the last glacial, and from 18 kaBP the tropical-subtropical pollen influx rose abruptly, while the herbaceous pollen influx and percentage dropped quickly, indicating that climate turned warmer and more humid, and more tropical-subtropical vegetation grew on the mainland and the emerging continental shelf, while the grassland on the shelf diminished. A detailed comparison shows an earlier change of pollen assemblages at the glacial- interglacial transition between MIS6 and 5 (Termination II) than the ice volume change indicated by the oxygen isotope record, implying that mid-low latitude climate warming pre- ceded ice sheet retreat. Millennial-scale climatic fluctuations of vegetation change in pollen record are also discussed.
This paper briefly presents the progress of deep-sea pollen research in China since the beginning of ninetieths of the last Century. All the deep-sea pollen contri- butions mainly come from the South China Sea (SCS) and the East China Sea (ECS). The German-Chinese joint cruise (Sonne 95) and ODP 184 cruise initiated by Chinese scientists in the SCS provided excellent material for the deep-sea pol- len research. So far a number of pollen results of 20—30 ka and million years from the SCS have been published. A couple of deep-sea pollen records from Okinawa Through of the ECS also came out. The high resolution pollen records obtained from the continuous deposits with high sedimentation rates and reliable age control of the deep-sea sediments provided a high time resolution history (hundred to millennial scales) of vegetation, environment and monsoon evolution of the pollen source areas (southern China and Japan). Spectral analysis of deep-sea pollen records from the SCS discovered orbital (100, 41, 23, 10 ka) and suborbital cyclicities (Heinrich and Dansgaard/Oscheger-O/D events) in the vegetation changes. Moreover, cross spectral analysis showed that the trend of vegetation changes in northern SCS was regulated mainly by changes of the ice volume in the Northern Hemisphere. The pollen record of the last 20 ka from the Okinawa Through of the ECS indicates that the marine environmental change lagged that on the terrestrail by about 1000 year. The asynchronous environmental changes between land and sea were probably caused by the time difference in thermohaline circulation. This study underscored the role of the deep-sea plant fossils as a bridge across the land and sea.
