天水黄土沉积特征与环境变化  

Loess Deposit Feature and Environmental Change in Tianshui,Gansu Province

作　　者：刘小丰[1] 潘保田[1] 高红山[1] 王勇[1] 王均平[1] 张慧[1] 胡春生[1] 

机构地区：[1]兰州大学资源环境学院/西部环境教育部重点实验室,甘肃兰州730000

出　　处：《中国沙漠》2007年第3期373-378,共6页Journal of Desert Research

基　　金：国家自然科学基金(40471016和40401007);NSFC创新群体基金(40421101);国家重点基础研究发展规划(2005CB422001)共同资助

摘　　要：中滩剖面系中滩镇渭河第四级阶地上的黄土堆积,通过黄土剖面的地层结构及粒度分析表明,其形成于0.9 Ma以来,河漫滩堆积年代为0.86—0.94 Ma。在过去1 Ma以来,中滩黄土及河漫滩剖面的地层特征、粒度曲线表明其记录了9个湿热干冷气候旋回,3次冬季风强化阶段,存在着3次极端干旱事件。中滩黄土粒度特征以粉砂为其众数粒级,其次为粘土颗粒,不同于黄土高原其他地区,可能与秦岭北麓的湿润环境及六盘山对冬季风的阻挡有关。Zhongtan section is loess deposits on the fourth terrace of Weihe River in Tianshui city of Gansu province. Based on stratigraphic feature and grain size curve, the loess was formed since 0.9 Ma BP, and the floodplain was deposited during 0.86-0.94 Ma. During the last 1 Ma, Zhongtan underwent nine moist hot-dry cold cycles, three winter monsoon intensifications, and three extremely dry events. Grain size date indicates that Zhongtan loess is different from other sections in the Longxi basin, which was caused by the uplifting of Liupan Mountain and moist environment in the flank of Qinling.

关 键 词：黄土 粒度曲线 黄土古土壤序列 气候旋回 1Ma 甘肃天水 

分 类 号：P532[天文地球—古生物学与地层学]