地理科学 ›› 1996, Vol. 16 ›› Issue (4): 365-369.doi: 10.13249/j.cnki.sgs.1996.04.365

• 研究报道 • 上一篇    下一篇

陇西盆地最老的风成黄土沉积——兰州烟洞沟剖面

朱俊杰1, 钟巍21, 李吉均1, 曹继秀1, 王建民1, 王建力1   

  1. 1. 兰州大学地理系, 兰州730000;
    2. 新疆大学地理系, 乌鲁木齐830046
  • 收稿日期:1995-03-01 修回日期:1995-11-20 出版日期:1996-07-20 发布日期:1996-07-20

THE OLDEST EOLIAN LOESS DEPOSITION IN LONGXI BASIN-YANDONGGOU PROFILE IN LANZHOU

Zhu Jiunjie1, Zhong Wei21, Li Jijun1, Cao Jixiu1, Wan Jianmin1, Wan Jianli1   

  1. 1. Department of Geography, Lannzhon University;
    2. Department of Geography. Xinjiang University
  • Received:1995-03-01 Revised:1995-11-20 Online:1996-07-20 Published:1996-07-20

摘要: 沉积于兰州黄河北岸山足面之上的烟洞沟风成黄土,剖面厚约120m,据磁性地层学研究,该剖面包括B/M界线、后贾拉米洛、贾拉米洛、考伯、奥尔都维、吉尔萨等事件,结合沉积速率推算,剖面底界的年代约为1.7MaB.P.

Abstract: The Yandonggou eolian loess profile, with the thickness of 120 m located on the north bank of Huanghe river in Lanzhou,deposited on a typical piedmont surface(i. e. the Gansu period piedment surface). Geomagnetic study on this profile shows that the B/M boundary is placed at the depth of 30 m descendingly; the post-Jaramillo and Jaramillo events are situated at the depth interval of 34.5-35.5 m and 41.5-53.5 m respectively, and the Cobb. Mnt event which was discovered in succession recently lies at the depth of 72 m in this profile. The stable positive polarity features of the lowest three samples reflect that they have stepped into the olduvai event period. Estimated combining with deposition-rate, this loess profile deposition began at about 1.7 Ma B. P. This is the oldest eolian loess profile obtained upto now in Longxi basin.