山陕峡谷张家湾230 ka BP以来黄土记录的环境信息  

The Environment Information Recorded in Zhangjiawan Loess since 230 ka BP

作　　者：曹新光[1,2] 王建力[1] 

机构地区：[1]西南大学地理科学学院,重庆400715 [2]黄冈师范学院商学院,湖北黄冈438000

出　　处：《西南大学学报（自然科学版）》2012年第4期123-128,共6页Journal of Southwest University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(40901006)

摘　　要：对山陕峡谷张家湾村蔚汾河阶地上沉积的黄土地层粒度—磁化率进行分析发现:沉积物的粒度—磁化率变化曲线能够很好地反映黄土—古土壤地层序列的变化.粒径小于5μm和大于40μm组份的体积分数曲线分别是夏季风和冬季风的良好替代性指标,通过粒度分析所绘制的各粒级组份体积分数曲线显示,古土壤S2、S1和Sm发育时期,东亚夏季风加强,粒径小于5μm组份的体积分数增大;黄土L2和L1堆积时期,冬季风有所加强,粒径大于40μm组份的体积分数增大.张家湾剖面的黄土记录只能在万年尺度上与深海氧同位素记录进行对比,整体上反映了最近230ka以来山陕峡谷东亚季风的演化过程.The ana on the terrace of lysis of grain size and magnet susceptibility in loess stratigraphy of Zhang jia-wan located Weifen River in the Shanshan Gorge reveals that the grain size-magnet susceptibility change curve of the sediment can well reflect the variation of loess-paleosoil stratigraphy. The percentages of grain size below 5μm and above 40μm are reliable proxies reflecting the variation of East Asian mon- soon in summer and winter, respectively. The curves of the percentages of different grain sizes indicate that the summer monsoon was strengthened during the depositional periods of S2, S1 and Sm and the win- ter monsoon was strengthened during the depositional periods of L2 and L1. The records in the loess pro- file of Zhangjiawan can be compared with the deep sea oxygen isotope record on the time scale of 10 ka only and has recorded the evolution of East Asian monsoon since 230 ka BP

关 键 词：山陕峡谷 黄土 磁化率 粒度 东亚季风 

分 类 号：P532[天文地球—古生物学与地层学] P951[天文地球—地质学]