中文摘要：

通过对杭嘉湖平原北苕溪附近的北湖桥钻孔（BHQ）距地表深度为4.775~19.000m采集的535块样品色度数据的分析，并结合粒度、总有机碳（TOC）等指标，探讨了研究区全新世气候环境变化。色度与粒度、TOC相关性分析表明，黄度（b^＊）与TOC含量呈显著负相关性，较高b^＊值代表较低湖面；在稳定水环境下亮度（L＊）高值代表较干冷环境。根据色度分析结果，BHQ孔所在区域早-中全新世环境经历了明显冷暖干湿变化。11.4~8.7cal.ka B.P.阶段早期气候总体偏冷干，后期逐渐转向暖湿，可能于8.7cal.ka B.P.前便已经进入全新世大暖期；8.7~8.0cal.ka B.P.阶段早期（8.7~8.4cal.ka B.P.）气候转向干冷，持续约300年，晚期（8.4~8.0cal.ka B.P.）气候总体为暖偏湿；8.0~5.7cal.ka B.P.气候暖湿，为全新世大暖期鼎盛阶段；5.7~4.2cal.ka B.P.气候总体暖偏干，其中5.7~5.5cal.ka B.P.期间出现持续约200年冷气候事件。

英文摘要：

An improved predicting of future climate variabilities and changes relies on high-quality data sets from the past, especially the Holocene.The Hangjiahu Plain, which is located in south of the Yangtze River and north of the Qiantang River, a part of the eastern coastal areas of China, is sensitive to the Holocene climate changes.During the Holocene, Hangjiahu Plain occurred transgressive and regressive for many times, and Neolithic sites distribute in this region widely.A drill core of lake-swamp sediment with depth of 4.775~19.000m was obtained from Beihuqiao （30°22.443＇N, 119°56.237＇E）.The dating data by 14C method indicate that the core spans the period of 11.4~4.2cal.ka B.P.Based on 535 color and granularity samples at 2.5cm intervals and 136 total organic carbon（TOC） samples at 10cm intervals, climate and environment during the Early-Mid Holocene was reconstructed. According to the color evolution rule, it can be divided into four stages to discuss （11.4~8.7cal.ka B.P., 8.7~8.0cal.ka B.P., 8.0~5.7cal.ka B.P.and 5.7~4.2cal.ka B.P.）.The color results were compared with granularity and TOC in each stage, which shows that the yellow degree index（b^＊） is markedly negative correlating with TOC, the correlation coefficient are -0.663,-0.719,-0.590 and -0.651, so that higher b^＊ indicates lower effective humidity.In addition, in the stabilized water environment, brightness index （L＊） is negative correlating with clay, so higher L＊ infers drier environment.Results of color, TOC, granularity, spore-pollen concentration and E/D（the percentage of evergreen/deciduous）analysis indicate that the study area has undergone significant environmental change.During 11.4~8.7cal.ka B.P., in the early of this stage（11.4~11.2cal.ka B.P.）the value of L＊ （66.01） and b^＊ （12.02） are high but on a declining curve, the percentage of TOC（0.33%） is low but on the raise, showing that the climate was a bit of cold and dry but changing to become warmer and wetter; in the late of this