中文摘要：

对兴凯湖长269cm的沉积岩心的研究结果显示：沉积物的色度和磁化率特征可以较好地反映区域气候环境变化。沉积物明度分别与红度、磁化率、黏土和有机质含量之间及磁化率与黏土之间有很好的相关性；红度高值与明度低值对应暖湿气候环境，磁化率低值反映沉积物较粗的较低湖面，对应冷干气候。28480-26160cal.aBP，湖区处于温湿气候时期；22880-18170cal.aBP，岩心孢粉浓度很低，流域处于末次盛冰期疏桦林草原环境；18170-12650cal.aBP处于Boiling／Older Dryas／Allerφd暖期。岩心深度90-78cm段，对应于新仙女木期；11500-4570cal.aBP，进入全新世暖期，其中8000-5000cal.aBP，本区处于全新世大暖期（气候适宜期）；4570-1470cal.aBP气候变为凉干；1470cal.aBP以来，流域又变为暖湿气候环境，同时，人类活动逐渐增强造成水土流失加剧。

英文摘要：

The Xingkai Lake, a transboundary lake by China and Russia, is the largest freshwater lake in Northeast Asia. We used diffuse reflectance spectroscopy and magnetic susceptibility to characterize the sediments in a 269 cm long core from deepwater in the northern part of the lake. Redness in sediment is primarily related to wet-warm climate, which seems to monitor paleoclimatic changes in the area; brightness has a good correlation with magnetic susceptibility, clay ,TOC and redness, and likewise, magnetic susceptibility with clay. As lacustrine sediment becomes coarser, magnetic susceptibility generally decreases in the core. So both brightness and magnetic susceptibility can be used as a proxy indicator of palaeocli- mate evolution in the area. Climate changes recorded by the lake sediments from Xingkai Lake were mainly characterized by the warm-wet and cold dry alternation,based on accelerator mass spectrometry （AMS） radiocarbon chronology. An extreme cold-dry period occurred during 28480-26 160 cal.aBP, especially during 27050-26160 cal. aBP. It was colder drier, with redness decreasing evidently. During 26160-22880 cal. aBP,redness reached the lowest value while climate transited to warm and wet conditions. 22880-18185 cal. aBP was a very cold period with very poor pollen grain in the sediments corresponding to the Last Glacial Maximum（LGM）. 18185-12650 cal. aBP was a frequent oscillation period of redness and magnetic susceptibility correlating with Boiling/Older Dryas/Allerod warm period. A sharp fluctuation of redness, brightness and magnetic susceptibility occurred around the Younger Dryas cold event, at about 90-28 cm depth in the core. During 11500-4520 cal. aBP, redness increased to higher values, indicating a wet and warm climate in Holocene, and 8000-5000 cal. aBP represented Holocene Megathemal period （Holocene thermal optimum） with the highest redness value of the horizon in the area. During 4570-1470cal. aBP,redness and magnetic susceptibility decreased markedly, reflecting the prevalen