中文摘要：

根据对云南腾冲青海湖泊沉积钻孔样品的粒度特征、总有机碳、碳酸盐、磁化率及年代学分析测试,探讨了各指标的变化特点及其环境指示意义,指出了云南高原湖泊沉积物化指标的特殊性及其变化特点.在此基础上,重建了云南腾冲地区末次冰消期（15830a B.P.）以来沉积环境与气候干湿变化历史.通过青海沉积物年代序列的重建和综合各物化参数分析得出,云南腾冲地区自15830a B.P.以来总体呈现冷湿-温湿-暖干-温和偏干的气候演变过程,并可分为4个阶段,即15830～12790a B.P.气候温凉偏湿;12790～4680a B.P.为温暖湿润期,湖泊水位高,气候湿暖,降水多;4680～312a B.P.气候特征呈现出从温湿到暖干气候逐渐演化,降水减少,湖泊水位下降;312a B.P.以来气候特征为前期温和湿润,后期具有暖干化特征,反映了近几十年来全球气候变暖导致的气候变化趋势并叠加了研究区人类活动对区域环境的影响.

英文摘要：

Qinghai Lake, which located at Tengchong County in Yunnan Province near the border between China and Myanmar （25°08＇06″～25°07＇44″N, 98°34＇11″～98°34＇26″E） ＇ is a small c~rater lake with an area of 0.21kin2, a maximum water depth of 5.9m and a drainage area of 1.5km2 （when the water level at 1885m a.s.1.）. According to the meteorological data, the annual average temperature is 14.7% , with a maximum temperature of 30.5℃ and a minimum temperature of -4.2℃ ; the annual average precipitation is 1425mm, among that the rainfall amount between May and October takes up 84.3%. the annual average potential evaporation amount is 1575mm, therefore, the study area is a tropical plateau humid monsoon climate. A 513cm long sediment core （25°07＇54″, 98°34＇17″） , which has been composed by two parallel cores took from Qinghai Lake has been studied. Our purpose is to understand how the grain size, paleomagnetic susceptibility, total organic （TOC） and inorganic （TIC） contents changed and what did these parameters mean. Based on 16 AMS 4C dates, the chronology of the core was established and the age at 513cm depth is 15830a B.P. Totally 513 sample were analyzed and based on the age-depth relationship it was calculated that each the samples analyzed possesses a resolution of 30-50 years. Among the four parameters we discussed, we found that the organic content in some part of the Tengchong core can be as high as 66. 60%, e.g. at 123cm （835a B.P.） depth in the core, while in some parts the CaCO3 content can be as low as zero, e.g. at 479-423cm （13560-11660 a B.P.） and 382-180cm （9690-2650 a B.P., excepth at 278 ～275cm, 5990-5940 a B. P.） depth in the core. We attribute the high TOC content to the very stable climate with not very high amount of precipitation. The extreme low TOC content is attributed to the out flow of the lake water when the input of the water amount excesses the capacity of the lake, due to the strong rainfall. According to the grain-size c