中文摘要：

分析了梁子湖8．35kaB．P．以来沉积物中有机质δ（^13C）的组成特征，并与代表印度洋季风的四川红原泥炭δ（^13C）序列及代表东亚季风的长白山哈尼泥炭δ（^13C）序列进行了对比，探讨了早全新世以来不同阶段的气候特点及古东亚季风与印度洋季风对该区的影响。研究表明，梁子湖在其形成演化过程中存在两种典型的湖泊沉积环境。5．98kaB．P．以前δ（^13C）值偏负，气候温暖湿润，有机质以湖泊内源水生生物为主，δ（^13C）值与湖泊生产力有关。其早期东亚季风对该区的影响占较大优势。全新世大暖期中期（5．98～3．67kaB．P．），气候持续暖湿，温度与降水达到顶峰，δ（^13C）值也达到序列中的最小阶段，其δ（^13C）值偏负与浮游生物生产力的增加有很大的关系。3．67～3．29kaB．P．是气候突变期，δ（^13C）值变幅达6‰。3．29kaB．P．以后δ（^13C）值逐渐偏正，气候逐渐变冷干，沉积环境发生较大变化，有机质以陆源C3植物碎屑为主，此时期东亚季风开始加强，印度洋季风持续减弱，但该区受印度洋季风影响更强烈。研究显示，东亚季风与印度洋季风强弱转换和时空迁移的影响对长江中游地区气候环境的演化具有重要作用。

英文摘要：

The organic matter δ（^13C） in lake sediments as a fine index is widely used in the IGBP research. Although its value is controlled by so many factors, great progress has been made in the research of palaeoclimatic condition of the Quaternary. Liangzi Lake, located in the middle of Yangtze River, is influenced by the East Asian summer monsoon（EAM） and the Indian Ocean summer monsoon（ISM）, so that it is sensitive to the climate change. The research shows that it has been experienced two different aggradational environments. The organic matter source was mainly hydrophily life-form in the lake before 3.67 kaB. P. with a negative value of δ（^13C）, illustrating that it was warm and wet . The EAM was stronger in the research area in the earlier Holocene Climatic Optimum. However, when it came to the end of Holocene Climatic Optimum（5.98- 3. 67 kaB. P. ） both EAM and ISM had a equal effect on the lake area. After 3.29 kaB. P. the climate changed to be drier and colder as terrestrial clastic matter gave more contribution to the orangic matter source. The area was influenced to a larger extent by the ISM when EAM became stronger and ISM became weaker.