青藏高原东南缘甘孜黄土磁化率揭示的西南季风演化  

EVOLUTION OF THE SOUTHWEST MONSOON ON ORBITAL TIME-SCALE REVEALED BY A LOESS-PALEOSOL SEQUENCE ON THE SOUTHEASTERN MARGIN OF THE QINGHAI-TIBETAN PLATEAU FOR THE LAST 1.16 Ma

作　　者：刘冬雁[1,2] 彭莎莎[1] 乔彦松[3] 谢瑞煌[4] 

机构地区：[1]中国海洋大学海洋地球科学学院,青岛266100 [2]中国海洋大学海底科学与探测技术教育部重点实验室,青岛266100 [3]中国地质科学院地质力学研究所,北京100081 [4]中国海洋大学海洋环境学院,青岛266100

出　　处：《海洋地质与第四纪地质》2009年第5期115-121,共7页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金项目(40472088)

摘　　要：以青藏高原东南缘甘孜A剖面黄土-古土壤序列为材料,在磁性地层学研究的基础上,对其高分辨率磁化率记录的多时间尺度气候特征进行了分析。磁性地层学研究结果表明,甘孜A剖面典型风尘堆积的底界年龄约为1.16Ma。磁化率记录在构造时间尺度上具有明显的阶段性,显示了西南季风演化存在中更新世气候转型。功率谱分析检出典型的偏心率100ka、斜率41ka、岁差23ka轨道周期和11.4、7.5ka的岁差拍頻周期,指示西南季风演化受天文因素影响,印度季风系统对太阳辐射具有非线性响应和热带特征。Climatic characteristics of different stages recorded by high-resolution magnetic susceptibility are discussed based on loess-paleosol sequence of Garze A section and also on magnetostratigraphy on the southeastern margin of the Qinghai-Tibetan Plateau. Periodicities of the earth＇s orbital parameters are detected by power spectral analysis and the evolution of the southwest monsoon on orbital time-scale is studied. The results show that （1） the cycle of quasi-100 ka does exsit in the evolution of the southwest mon- soon, and the obliquity cycle and precession cycle are remarkably detected as well; （2） the beat frequency periods of the precession are detected and give a strong non-linear response to the solar insolation and the tropical climatic characteristics of the southwest monsoon; （3） the mid Pleistocene transition which was recognized in the evolution of the southwest monsoon began approximately 0.95 MaBP and ended around 0.6 MaBP.

关 键 词：甘孜黄土磁化率 西南季风 青藏高原 

分 类 号：P532[天文地球—古生物学与地层学]