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通常认为青藏高原东南部第四纪曾发育过一个冰帽——稻城冰帽,然而关于这个冰帽发育的年代和变化的过程,还缺乏足够的年代数据的支撑。本文选自稻城第四纪古冰帽南缘雄古附近的冰碛垄、冰碛台地、羊背石和冰川漂砾进行了宇生核素~(10)Be和~(26)Al暴露年代测定。结果显示,稻城古冰帽南缘至少发生过5次冰川前进事件,每次冰川前进到达最大规模的时间分别为19.0±0.7～19.8±0.7kaB.P.,25.8±0.6～27.4±0.7kaB.P.,52.5±0.9～59.6±1.1kaB.P.,162.2±2.7～287.4±9.9kaB.P.和大于480.2±2.2kaB.P.。根据年龄数据以及空间位置关系的分析,稻城古冰帽很可能形成于约800～600kaB.P.之间,此后冰川的规模呈现出随着时间不断缩小的趋势,可能与该区气候的变干有关。MIS 3的冰川规模比MIS 2大,可能与MIS 3时期气候比MIS 2相对湿润有关。
It is generally believed that a glacial cap-Daocheng ice cap has been developed in the southeastern part of the Qinghai-Tibet Plateau. However, there is not enough time to support the age and change of this ice cap development. This paper was selected from the moraine ridge, moraine terrace, sheep backstone and glacial boulder located near the southern margin of the ancient paleo-ice cap in the Daocheng area of Daocheng City for the dating of ~ (10) Be and ~ (26) Al. . The results show that at least five glacier advance events occurred in the southern margin of the Ancient Ice Cap in Daocheng City. The maximum time for each glacier advance reached 19.0 ± 0.7 ~ 19.8 ± 0.7kaB.P. and 25.8 ± 0.6 ~ 27.4 ± 0.7kaB respectively. P., 52.5 ± 0.9 ~ 59.6 ± 1.1kaB.P., 162.2 ± 2.7 ~ 287.4 ± 9.9kaB.P., and greater than 480.2 ± 2.2kaB.P. According to the analysis of age data and spatial location, it is likely that the ancient ice cap in Daocheng was formed between about 800 and 600kaB.P., and the scale of the glacier then shows a trend of shrinking with time, which may be related to the climate of the area becoming dry related. The glacier scale of MIS 3 is larger than that of MIS 2, which may be related to the relative humidity of MIS 2 in MIS 3.