黄河中游渑池盆地湖泊沉积记录的古气候变化及其意义

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

渑池盆地位于黄河中游,处在黄土高原向华北平原的过渡地带,该区域也是我国东部湿润区和半湿润区的交汇地带。文章通过对位于渑池盆地池底村厚约4mm古湖泊沉积剖面进行了^(14)C年代(校正为日历年龄)、有机碳含量、粒度和地球化学元素组成等测试分析,重建了研究区19.5cal.kaB.P.以来的气候变化过程。19543～9240cal.aB.P.期间,气候比较干旱,风化淋溶作用较弱,湖泊尚未形成;9240～8039eal.aB.P.为气候过渡时期,气候向暖湿方向转变,古湖泊开始形成;8039～5368cal.aB.P.为暖湿气候类型,对应于全新世大暖期的鼎盛时期,湖盆流域温暖湿润,湖泊的水位较高;5368～3439cal.aB.P.为亚暖湿气候类型;3439～2423cal.aB.P.气候环境比较恶劣,之后气候向干旱化方向发展,又分为两个亚段:3439～2931 cal.aB.P.气候出现剧烈波动,2931～2423cal.aB.P.湖泊干枯。盆地的文化演进与环境变化间存在着耦合关系,环境的变化对应黄河中游地区相继发展的裴李岗文化、仰韶文化、龙山文化和夏商文化。

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, 4kin 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 14C 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 - 9240eah 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 palaeoelimate 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 warmhumid, 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.