Pollen Assemblages And Environment Since The Late Pleistocene In Changzhou Region

Changzhou area is located in the south of Jiangsu province which is between thenorth subtropical to the north temperate zone, a transitional area between the westerninland and eastern coastal area in China. It is in the middle-lower reaches of theYangtze River and the monsoon climate zone. It has significant importance to doresearch on its climate evolution to reveal the temporal and spatial variations of theEast Asian monsoon and the global climate change. The vegetation flourished now,but in the geologic historical period, it has experienced the glacial and interglacialperiod, the climate changed frequently. This paper based on a field drilling detectionin Changzhou area and analysis of a large number of effective test data (dating, suchas14C, OSL, ESR, pollen and grain size, etc.) the application of other indicators, findout the strata and environmental evolution system in Changzhou area since latePleistocene by using various indicator analysis research methods, the combination ofqualitative and quantitative analysis and previous research data makingcomprehensive comparison of the study area and making contribution to the laterresearch on Quaternary environment revolution and other related research in thisregion. Research results are as follows:1. From top to bottom, in the late Pleistocene period, the strata of BK1hole canbe divided into the Kunshan Group (Qp3K) in the lower part, Gehu Group (Qp3G) inthe middle, and Holocene Rudong group (QhR) at the top.2. According to the characteristics of pollen assemblages and combined withlithologic grain size reflected in the study area, it can be concluded:125～83ka B.P.,the warm humid climate changed into cool and humid climate.83ka B. P.～11ka B.P., it experienced cold-humid climate, warm-humid climate, cold-dry climate.11ka B.P. to present, the climate became warm and humid.3. From the research, it can reconstruct the sedimentary environment model inthe in late Pleistocene period in study area, it experienced the early Late MioceneTaihu transgression, late Pleistocene lake Gehu transgression period, Holocene warm period, the climate change can be roughly divided into6stages.4. The climatic and environmental changes in the study area coincidence withglobal climate change which means that they both control by the same factors. Dueto the special regional location and tectonic characteristics, reflects the particularity ofthe climate response, mainly displays in: In the background temperatures rised inMIS5phase, Taihu lake transgression happened. And in the late MIS3period, climatewarm wet period Gehu transgression happened.