贡嘎山地区全新世的冰川变化、气候变化与河谷阶地发育

THE GLACIER VARIATION,CLIMATIC CHANGE AND THE RIVER VALLEY DEVELOPMENT IN THE HOLOCENE ON THE GONGGA MOUNTAINS

本区冰川变化与河谷阶地发育关系密切，全新世初气候转暖，冰川逐步后退，形成第四级河流阶地（Ｔ４下部），全新世中期的高温期（７５００－４０００ａＢＰ）冰川强烈消融，形成第四级阶地（Ｔ４中上部）＜７４２０±９０ａＢＰ；全新世晚期气候转冷，新冰期可分出三次冰进：前观景台冰进＞３０８０±８０ａＢＰ，观景台冰进１５５０±８０－２３５０±６５ａＢＰ，海螺沟冰进９４０±８５－７８０±９０ａＢＰ，相应出现Ｔ３＞３０００ａＢＰ，Ｔ２１２００±７０－２１７０±６０ａＢＰ，Ｔ１９３０±７０ａＢＰ，现在小冰期最早出现在４００年前，有３次波动，相当于公元１６０３－１６５０；１７５１－１８００；１８５１－１９００；三次气候寒冷期。

On the Gongga Mountains, the relationship between the glacier variation and the development of the river terrace is very close.In the early Holocene, the climate became warm, and the glaciers gradually retreated. The fourth fluvial terrace was formed(T4) (the lower section) .In the Hypasithermal period of the middle Holocene(7 500-4 000aBP),the glaciers retreated strongly. The middle and upper sections of the fourth terrace were formed (T4)(<7 420 ± 90aBP).In the late Holocene,the climate turned to be cold and the Neoglaciation can be divided into three stages:the pre-Guanjingtai glacier(<3 080± 80aBP) , the Guanjingtai glacier(1 530± 80-2 350 ± 65aBP), and the Hailuogou glacier(840 ± 85-780 ± 90aBP). The three terraces were respectively : T3 : >3 000aBP, T2 : 1 200±70-2 170± 60aBP and T1: 930 ± 70aBP. The earliest Modern Little Ice Age appeared in 400aBP ,and there were three time of climate waving. They occurred in the periods of 1603-1650AD, 1751- 1800AD, 1851-1900AD──the three cold climate periods.