兰州盆地黄河800ka B.P.阶地的发现及其古地磁年代  

Discovery and Paleomagnetic Dating of 800ka B.P. Terrace of the Yellow River in Lanzhou Basin

作　　者：胡春生[1] 潘保田[2] 苏怀[3] 李吉均[2] 

机构地区：[1]安徽师范大学地理系,安徽芜湖241000 [2]兰州大学地理系,甘肃兰州730000 [3]云南师范大学地理系,云南昆明650000

出　　处：《地理科学》2009年第2期278-282,共5页Scientia Geographica Sinica

基　　金：国家自然科学基金项目(批准号:40471016);国家重点基础研究发展规划项目(批准号:2005CB422001);安徽师范大学青年基金项目(批准号:160-720777)资助

摘　　要：兰州东盆地的枣树沟黄河第四级阶地(T4),砾石层顶高出黄河河面84 m,其上堆积厚约64 m的风成黄土,黄土地层中包括八层古土壤,最底部发育了古土壤S8。光释光(OSL)测年结果显示古土壤S1上部的年龄为70.4±7.6 ka。黄土古土壤对比以及磁性地层学研究表明,枣树沟T4上覆风成黄土的年龄为865 ka,T4至少形成于865 ka B.P.。The research on Yellow River terrace is the fourth terrace of Zaoshugou section in Eastern Lanzhou Basin, and the altitude of gravel stratum is 84m higher than the river level. The top of the gravel stratum is covered by at least 64m eolian loess, and the paleosol S8 is at the bottom of the eolian loess. The optically stimulated luminescence （OSL） dating result indicates that the age of the upper part of paleosol S1 is 70.4 ± 7.6ka. Paleosol-loess matching and research on magnetostratigraphy show that the bottom age of eolian loess on the fourth terrace is 865ka, therefore this article holds that the fourth terrace of Zaoshugou section develops no later than 865kaB. P.

关 键 词：兰州盆地 黄河阶地 800ka B.P. 古地磁年代 发现 

分 类 号：P931.1[天文地球—自然地理学]