地理科学 ›› 2000, Vol. 20 ›› Issue (3): 259-263.doi: 10.13249/j.cnki.sgs.2000.03.259

• 论文 • 上一篇    下一篇

临夏盆地晚中新世以来的风沙沉积及环境意义

王建力1, 方小敏2   

  1. 1. 西南师范大学地理系, 重庆400715;
    2. 兰州大学地理科学系, 甘肃兰州730000
  • 收稿日期:1999-03-09 修回日期:1999-06-23 出版日期:2000-05-20 发布日期:2000-05-20
  • 基金资助:
    中国科学院"九五”青藏研究项目(KZ951-A1-204-02-01)和国家自然科学基金项目(49871010)的资助.

Eolian Sand Deposition and Its Environmental Significance in Linxia Basin Since Middle Miocene

WANG Jian-li1, FANG Xiao-min2   

  1. 1. Dept. Geography, Southwest China Normal University, Chongqing 400715;
    2. Dept. Geographical Science, Lanzhou University, Lanzhou 730000
  • Received:1999-03-09 Revised:1999-06-23 Online:2000-05-20 Published:2000-05-20

摘要: 对临夏盆地1Ma以来地层中的石英砂所作的扫描电镜分析表明,风成砂一直存在,并在8Ma和6~Ma时含量最高.最大颗粒的平均粒径在(1.5~3.6)/2.6Ma达0.4mm,3.6~2.6Ma之后显著下降.前者表明3.6~2.6Ma以前,近源风沙作用一直存在,并在8Ma和6~Ma达到最盛;后者表明第四纪以来,远源风沙沉积盛行,可能反映了青藏高原在3.6~2.6Ma急剧隆起和与之相关的大气环流的改变.

Abstract: Atotal of 55 samples were taken from the Tertiary red earth and Quaternary lacustrine deposits and loess for Linxia Basin for the analysis of quartz type and content using electron probe microanalyzer. The eolian sand contents appeared two high values at about 8Ma and 6-5Ma respectively. The mean size of quartz grains was about 0.4mm during the 15-3. 6/2. 6 Ma period and dropped down to 0.1mm dramatically after 3. 6-2. 6Ma. These results mean the eolian deposition reached its maximum at 8 Ma and 6-5 Ma respectively. Since the Quaternary, the local eolian deposition was decreased significantly and disappeared which was replace by dust deception from far source, suggesting the uplift of Qinghai-Xizang Plateau and the change of air circulation.

中图分类号: 

  • P534.63