摘要
青藏高原东北部最近１５万年中至少存在４次多年冻土强烈扩展时期。第一次发生在１４０ｋａＢＰ的倒数第二次冰期，各地广泛发育冰楔；第二次发生在末次冰期早期（８０～５３ｋａＢＰ），若尔盖盆地发育融冻扰曲；第三次发生在２７～２３ｋａＢＰ，高原东北缘出现冰楔；第四次发生在２１～１０ｋａＢＰ，巴颜喀拉山以南地区和若尔盖盆地发育冰楔，黄河源、共和及青海湖周围出现原生砂楔。不考虑构造上升。
In the northeastern Qinghai-Tibetan Plateau, There were at least four periods in which permafrost intensive expanded during the last 150 ka BP. The first one, in which ice wedges extensively developed,was the penultimate glaciation 140 ka BP. The second was early Last Glacial(80～53 ka BP),when involution appeared in Zoige Basin. Ice wedges developed in Gonghe Basin and Qinghai Lake region in the third Period(27～23 ka BP). In the fourth period from 20 to 10 ka BP, regional difference of natural environment became very clear. Ice wedges developed in Zoige Basin and Bayanhar Mountain because of humid and cold climate. However, sand wedges appeared in the source of the Yellow River, Gonghe Basin and Qinghai Lake region due to the dry and cold climate. The altitudes of lower limits of permafrost zone in the cold periods were 1 700～1 800 m lower than the present, leaving out the tectonic uplift.
出处
《冰川冻土》
CSCD
北大核心
1997年第2期123-132,共10页
Journal of Glaciology and Geocryology
基金
国家自然科学基金
关键词
多年冻土
冻土演化
青藏高原
permafrost evolution, ice-wedge casts, fossil sand wedges, the northeastern Qinghai-Tibetan Plateau
