PALAEOCLIMATIC CHANGES SINCE THE DEGLACIATION REVEALED BY LACUSTRINE SEDIMENTS IN MIANCHI BASIN OF WESTERN HENAN PROVINCE,CENTRAL CHINA AND THE IMPLICATION FOR CHINESE CULTURE DEVELOPMENT
黄河中游渑池盆地湖泊沉积记录的古气候变化及其意义

Mianchi Basin is located at the Middle Yellow River,west of Henan Province,Central China. It is on the transitional zone of Loess Plateau and North China Plain, and it is also on the transitional belt of humid to semi-humid region. This place was one of the birthplaces of the Chinese Civilization. The profile we researched locates in the south of the Chidi Village, 4km southeast away from Mianchi Basin County and 3km northeast away from Yang Shao Remains. We dug from 1.5m deep to 5.5m deep and totally 4m long was researched. We took 14 C dating samples from the profile at 80cm, 153~161cm, 270~275cm and 390~395cm respectively and date them with liquid scintillation method, the result shows the age of the profile range from 19543cal.aB.P. to 2360cal.aB.P. Based on analysis of grain size,total organiccontent(TOC)and geochemical elements,five palaeoclimatic stages have been identified:(1)During 19543~9240cal.aB.P. ,the soil weathering and eluviation process was weak and the climate was dry.The lake was not formed; (2)during 9240~8039cal.aB.P. ,it was a transition period of the climatic changes; the palaeoclimate was much warmer and humid than that in the earlier time,as evidenced by intensification of the soil weathering and the eluviation was stronger,lake environment was formed; (3)during 8039~5368cal.aB.P. ,the climate was turned to a warm and humid phase.The palaeoclimate was warmer and more humid,and the paleolake level was higher than that in before; (4)during 5368~3439cal.aB.P.It was also warm-humid,but the temperature and humidity were lower than that in the previous phase.The lake level declined; (5)during 3439~2423cal.aB.P. ,it was a dry and cold period,and the paleolake gradually dried up.The cultural development and the environmental changes probably are coupled in the investigated regions,where the Peiligang Culture,the Yangshao Culture,the Longshan Culture and the Xia and Shang Culture were sequently evolutive and were associated with the palaeoenvironmental changes.