【摘要】 冰缘地貌与沉积是冰冻圈环境变化的载体,对其开展深入研究对了解青藏高原地表过程与过去气候变化,具有重要意义。基于青藏高原(格尔木-亚东)冰缘地貌和沉积野外记录和实验分析,获得以下认识:格尔木在LGM时多年冻土至少下限到达海拔2 900m,年均气温降至<-4℃,比现在至少低9℃,气候寒冷干燥;冰消期和全新世存在极端干冷的气候事件,可能存在地面温度<-10℃的冬季迅速降温气候期。楚玛尔、那曲谷露和纳木错的冰楔假型分别记录了末次冰期冷期多年冻土扩张,亚东古砂楔记录了早全新世冷事件。西藏羊八井泥炭沉积剖面孢粉和测年揭示,该区自新仙女木事件以来经历了严寒(12.8～9.8ka)、暖湿(9.8～5.0ka)、干冷(5.0ka至今)的气候阶段。青藏高原(格尔木-亚东)广泛发育的冻融褶皱、成层坡积、风沙沉积等,是古环境重建的重要佐证,具有刻画冷暖-干湿的意义。更多还原

【Abstract】 Based on evidences of periglacial landforms and deposits along Golmud and Yadong,and age constraint,this paper discusses the environmental characteristics of periglacial evolution on the North-South section of the central Qinghai-Tibet Plateau since the Last Glacial period. The evidences at Golmud show in LGM,the permafrost reaches at least2 900 m above sea level,the annual average temperature drops to <-4℃,which was at least9℃ lower than the present,and the climate is cold and dry;there are extremely dry and cold climate events in the deglaciation period and Holocene,and there may be a rapid cooling climate period in winter when the ground temperature was less than-10℃. The Ice wedge pseudophorms at Qumar River,Gulu(Naqu),and Nam Co recorded permafrost expansion during the Last Glacial period. The relict ice wedge at Yadong recorded early Holocene cold events. Palynological and dating evidences of the peat section at Yangbajing indicate that the area has experienced four climatic stages since the Younger Dryas event:severe cold(12.8～9.8 ka),warm and humid(9.8～5.0 ka),dry and cold(5.0 ka to present). The widely developed involutions,stratified slope deposits and eolian deposits in the study area are important evidences have the value of depicting temperature and precipitation variation for paleoenvironment reconstruction.更多还原