地理科学

地理科学 ›› 2004, Vol. 24 ›› Issue (1): 101-104.doi: 10.13249/j.cnki.sgs.2004.01.101

• 论文 • 上一篇    下一篇

利用宇生核素测年技术对青藏高原东南部冰蚀面年代的研究

徐孝彬1,2, 王建2, 朱捷1, 姜洪涛1, 杨亦青1   

  1. 1. 江苏教育学院地理系, 江苏 南京 210013;
    2. 南京师范大学地理科学学院, 江苏 南京 210097
  • 收稿日期:2003-01-13 修回日期:2003-04-12 出版日期:2004-01-20 发布日期:2004-01-20
  • 基金资助:
    教育部"教育振兴计划"青年教师奖励基金项目(2001DLXSBJBC12)资助、江苏教育学院科学研究"十五"规划项目资助。

Study on Glacial Erosion Surface of the Southeast of Qinghai-Xizang Plateau Using Cosmogenic Isotopes Dating

XU Xiao-Bin1,2, WANG Jian2, ZHU Ji1, JIANG Hong-Tao1, YANG Yi-Qing1   

  1. 1. Geographical Department, Jiangsu Institute of Education, Nanjing, Jiangsu 210013;
    2. Geographical Science College of Nanjing Normal University, Nanjing, Jiangsu 210097
  • Received:2003-01-13 Revised:2003-04-12 Online:2004-01-20 Published:2004-01-20

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28 | 7

摘要： 分析理塘与稻城之间库昭-桑堆处的冰蚀面以及兔儿山北侧宽谷中的羊背石的宇生核素10Be,研究结果表明,库昭-桑堆处的冰蚀面暴露于133.4 ka B.P.,即倒数第二次冰期大约结束于133 ka B.P.,这一时间与深海氧同位素第6期相吻合。兔儿山北侧的冰川作用大约结束于18.5 ka B.P.,即末次冰期大约结束于18.5 ka B.P.,这一时间与深海氧同位素第二期相吻合。由同一地区的两个样品X8、X9得出相同的测年年代,并从样品X6得出的测年年代与野外观测的结论相一致来看,运用宇生核素10Be对冰蚀面的形成年代进行测年是一个行之有效的测年技术,并且还可运用于火山熔岩、断层、侵蚀阶地等其它地貌面的测年,该测年技术具有很大的运用潜力。

Abstract: With the development of the technique of cosmogenic isotopes dating, the formation age of glacial surface can be calculated now. Its principle is that the cosmogenic isotope concentration in the surface rock is a function of age, erosion rate and uplift rate of plateau. Samples of X8 and X9 are taken from the up-surface of glacial boulder in Kuzhao-Shangdui. Sample of X6 is taken from the up-surface of roche moutonnee in valley of the north of Mountain Tuer. The concentration of the cosmogenic isotope 10Be can be got from measure and calculation. According to field exploration, the rock surface where samples X8 and X9 are taken from is erosed about 9 cm in the exposure age t. It means that the erosion rate is about 9/t (cm·a). Then, the t (133.4 ka) can be calculated. Because having the same geographical environment, the rocke moutonnee has about the same erosion rate with the rock. The t (18.5 ka) can be calculated. The study shows that the glacier boulder was formed in 133.4 ka B.P. and the roche moutonnee was formed in 18.5 ka B.P. It can be concluded that Daocheng ice cap was about current in 133.4 ka B.P. (stage 6 of oxygen isotope of deep sea) and the glaciation in the valley occurred about in 18.5 ka B.P.(stage 2 of oxygen isotope of deep sea). The same result coming from two samples X8 and X9 taking from same glacier boulder, and the result from X6 being in concordance with field exploring show that the cosmogenic isotopes dating technique is a effective method in dating surface of landforms.

中图分类号: 

  • P931.4