河北阳原盆地井儿洼剖面常量元素地球化学特征揭示的中更新世晚期以来气候变化

Climate change since the late Middle Pleistocene indicated by geochemical characteristics of major elements of Jing’erwa section in Yangyuan Basin,Hebei Province

阳原盆地发育一套第四纪河湖相地层,其中分布着丰富的古人类遗存,是研究古人类生存环境的理想地区之一。利用常量元素氧化物含量及其比值,研究了阳原盆地井儿洼剖面河湖相沉积物地球化学元素特征,以及阳原盆地近220ka以来的气候变化过程。结果表明：（1）井儿洼剖面沉积物成分以Si O2、Al2O3和Ca O为主,含量范围分别为27.85%-53.23%、3.38%-12.97%和5.43%-28.36%;Fe2O3和Mg O含量也较高（变化范围分别为2.65%-7.67%和1.93%-14.42%）,整体反映出半湿润—半干旱的沉积环境。（2）该区域中更新世晚期以来的气候表现为暖湿—偏冷偏湿—暖偏湿—凉偏湿—暖干的变化特征;各阶段水热组合特征以及内部明显的次级气候波动,显示了环境演化的复杂性。（3）与深海氧同位素阶段的对比表明,本区气候变化与全球变化具有一致性的同时也存在明显的区域特征。

Filled up by a succession of Quaternary fluvial and lacustrine sediments,and containing a large number of remains of ancient human beings,Yangyuan Basin is one of the ideal regions to study the living environmental background of ancient human beings.Based on the contents and their ratios of major element oxides,geochemistry elements characteristics of Jing＇erwa section as well as the climate changeprocess of Yangyuan Basin since 220ka were studied.The results showed that：（1） The sediment of Jing＇erwa section was mainly composed of Si O2,Al2O3 and Ca O,with the contents of 27.85% - 53.23%,3.38% - 12.97% and 5.43% - 28.36% respectively.Contents of Fe2O3 and Mg O,with the range of2.65% - 7.67% and 1.93% - 14.42% respectively,are also considerable.Those reflected the environmental change from semi-humid to semi-arid.（2） The climate in this area since the late Middle Pleistocene varied from warm-wet,slightly warm-slightly wet,warm-slightly wet,cold-slightly wet to warm-dry.Features of hydrothermal combination and evident secondary climatic fluctuations of each period reflected the complexity of environmental evolution.（3） Comparison with the oxygen isotope phases of deep sea shows that the changing process of climate for the Yangyuan Basin not only responds to the trend of the global climate change but also bears obvious regional features.