六盘山东西两侧黄土古土壤容重的特征及其古气候指示意义  

Characteristics of Loess-Paleosols Volumetric Weight in the Eastern and Western Liupanshan and Its Paleoclimate Significance

作　　者：靳春胜[1] 黄孝刚 张立原[1] 袁四化[3] 梁文天[4] 刘东生[1] 

机构地区：[1]新生代地质与环境重点实验室、中国科学院地质与地球物理研究所,北京100029 [2]深圳市勘察测绘院,广东深圳518028 [3]成都地质矿产研究所,成都610081 [4]西北大学大陆动力学国家重点实验室,西安710069

出　　处：《地质学报》2008年第5期702-709,共8页Acta Geologica Sinica

基　　金：2003年度中国国家最高科学技术奖资助成果

摘　　要：为了进一步了解黄土古土壤容重的特征及其与东亚季风演化的关系,建立了洛川剖面250ka以来、白草塬剖面140ka以来黄土古土壤容重序列,并与磁化率、粒度及深海氧同位素对比分析,发现六盘山东西两侧不同气候区黄土古土壤容重具不同的特征和受控因素,指示了不同的古气候意义。六盘山以东半湿润半干旱气候区容重值受成壤作用影响,容重指标主要由夏季风控制,可作为夏季风演化的替代性指标。而六盘山以西半干旱气候区,容重值受沉积物粒度影响,主要由冬季风控制,可作为冬季风演化的替代性指标。与灵台和三门峡地区黄土古土壤容重值对比,发现空间上由西北向东南容重值呈变大趋势,进一步表明了不同气候区的冬夏季风对容重指标的不同影响。To further understand the relations between volumetric weight and the East-Asian monsoon evolution, we established volumetric weight sequences of loess-paleosols at the Luochuan section since 250 ka BP and Baicaoyuan section since 140 ka BP, respectively. Comparison between volumetric weight, magnetic susceptibility, particle size and deep-sea oxygen isotope show that loess-paleosols volumetric weight in different climate regions east and west of the Liupanshan indicates different paleoclimate significance mainly controlled by different climate factors. Loess-paleosols volumetric weight is controlled by East-Asian summer monsoon in semi-humid and semi-arid region lying in east to the Liupanshan, whose values are influenced by pedogenesis, and by East-Asian winter monsoon in semi-arid region west of the Liupanshan, whose values are influenced by particle size, and can be employed as a proxy indicator of summer monsoon evolution and winter monsoon evolution in the above-mentioned two climate regions, respectively. Compared with sections in Baicaoyuan, Luochuan, Lingtai and Sanmenxia, volumetric weight values increase spatially from northwest to southeast in China, further indicating different influences of summer and winter monsoon on volumetric weight values of different climate region.

关 键 词：黄土古土壤 容重 季风演化 六盘山 洛川 白草塬 

分 类 号：P532[天文地球—古生物学与地层学]