【摘要】 根据洱海湖泊沉积物有机碳稳定同位素、元素、磁化率记录,近8 ka来西南季风区洱海古气候演化可以分为9个阶段,气候变化以暖干-冷湿交替为主,暖干气候阶段西太平洋副热带高压控制西南地区的频率增加,夏季印度季风路径偏向西亚、中亚和青藏高原西部,包括洱海在内在云南高原气候暖干明显;冷湿气候阶段,副热带高压偏弱向东撤退,印度季风路径移向中国西南地区,降水增加,造成气候冷湿.湖泊沉积物记录的洱海流域人类耕作农业历史最早出现在5 ka BP左右.更多还原

【Abstract】 The Indian monsoon is an important part of the Asian monsoon system,which strongly influences the climate in the Yunnan Plateau,southwest China.In this study,a 210 cm core that covered the sedimentary history of past 8 ka was sampled from the central part of Erhai Lake.Based on the data of organic carbon stable isotope,elements,magnetic susceptibility,the climate changes in the past 8 ka was reconstructed and divided into nine stages.On the time scale of 1 000 yrs,the climate changes recorded by the lake sediments from Erhai Lake was mainly characterized by the warm-dry and cold-wet alternation,which was a regional response to the Asian monsoon changes under the background of past global changes in Holocene.In the warm-dry period,the Northwest Pacific Subtropical High frequently controlled the southwest China and the Indian monsoon route moved to the westward regions,such as the West Asia,Central Asia as well as the Tibet Plateau;In the period of cold-wet,the Northwest Pacific Subtropical High moved eastward and the main Indian monsoon migrated to southwest China,bringing more rainfall and the climate turning cold-wet.The earliest human activities in the region around Erhai Lake occurred at 5 ka BP recorded by the proxy of frequency of magnetic susceptibility and the multi-environmental proxies varied complexly.更多还原