中文摘要：

选择位于西风区的吉力湖为研究对象，利用^210Pb、^137Cs和AMS^14C测年手段，建立了吉力湖沉积岩芯2．5ka以来的时间序列．对湖泊沉积物的粒度、总有机碳、总氮以及有机碳同位素等多环境指标的综合分析，重建了吉力湖2．5ka以来的气候环境演化特征．2．5ka以来吉力湖气候环境变化大致经历了5个阶段：500BC-50BC，暖干；50BC-650AD，冷湿，气候不稳定，冷暖波动较大；650—1350AD，暖干，对应于中世纪暖期（MWP），1350—1850AD，冷干，对应于小冰期（LIA）；1850AD以来，温于，其中20世纪20年代后，尤其是70年代以来，气候变暖．吉力湖多环境指标记录的气候环境变化与其它地质记录以及历史文献记录均具有较好的一致性．

英文摘要：

An 80-cm-long sedimentary core from Lake Jili, which lies in westerly area of China, provided detailed information about paleoclimatic and paleoenvironmental changes in the past 2500 years. The temporal sequence of sedimentary core was constructed using the ^210 Pb, ^137 Cs and AMS ^14C dating methods on the bulk organic matter. Based on analyses of grain-size, total organic carbon, total nitrogen and organic carbon isotope, climatic and environmental evolution history in the past 2500 years was reconstructed. The sequence of climatic changes in the region since 2.5ka BP was established. The climatic changes experienced five stages ： warm-wet climate during 500BC - 50BC ; cold-wet climate during 50BC - 650AD ; warm-dry climate during 650 - 1350AD warm period（MWP） ; cold-dry climate period during 1350 -1850AD（ LIA）, and moderate-dry since 1850AD, including climate warming after 1920s, especially since 1970s. The records of climatic and environmental evolution of Lake Jili were in good according with the historical literature records and other geologic records of adjacent areas＇.