摘要
在宁夏清水河下游 (北纬 37 4°,海拔 12 30m左右 )晚更新世湖相地层中 ,发现了晚更新世晚期的冰卷泥 ,表明当时多年冻土的南界在宁夏一带可扩展到北纬 37 4°附近 ,与现今相比 ,年均气温降低了 8～ 9℃。青藏高原东北缘的弧形山地中 ,晚更新世强烈的构造抬升以及末次冰期的干冷气候最终导致清水河堰塞成湖并在湖泊边缘的沉积物中形成了冰卷泥。
In the lake\|face strata located in the lower reach of the Qingshuihe River,Ning xia with the latitude of 37 4° N and the elevation about 1?230?m,involution dated in late period of late Quaternary was discovered,which indicates that the south limit of permafrost had once expanded approximately to the latitude of 37 4° N in that time in Ningxia and that the annual mean temperature was 8～9℃ lower than today.Because the intensive tectonic uplift in the northeast margin o f Tibetan Plateau and cold and dry weather in the last glacial maximum,the Qings huihe River was so blocked that along the margin of the blocked\|lake the involu tion was developed.
出处
《北京大学学报（自然科学版）》
CAS
CSCD
北大核心
2000年第5期714-718,共5页
Acta Scientiarum Naturalium Universitatis Pekinensis
基金
国家自然科学基金资助项目!(497710 13)
关键词
冰卷泥
多年冻土
晚更新世
宁夏
清水河下游
involution
permafrost
late period of late Quaternary
the lower reach of Qings huihe River,Ningxia
the northeast margin of Tibetan Plateau
