【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10 Be ,研究结果表明 ,库昭 -桑堆处的冰蚀面暴露于 133.4kaB .P .,即倒数第二次冰期大约结束于 133kaB .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 18.5kaB .P .,即末次冰期大约结束于 18.5kaB .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10 Be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。更多还原

【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.更多还原