晚第四纪科尔沁沙地干湿变化的黄土记录  

The Wet-dry Variations of The Horqin Sandy Field Recorded by Loess Deposit of The Late Quaternare

作　　者：弋双文[1] 鹿化煜[1] 周亚利[1] 苗晓东 

机构地区：[1]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室 [2]University of Wisconsin Madison,WI 53706,USA

出　　处：《中国沙漠》2006年第6期869-874,共6页Journal of Desert Research

基　　金：国家杰出青年科学基金(40325007);中国科学院国际合作交流项目(2003-353);美国科学基金会项目(GrantBCS-0352683和0352748)联合资助

摘　　要：利用光释光(OSL)定年技术对科尔沁沙地南缘的典型黄土剖面进行了测年,结合两个剖面的磁化率、粒度、有机质含量等气候替代性指标,对沙地古气候及环境变化过程进行了分析。结果表明,晚第四纪科尔沁沙地的古气候经历了万年-千年时间尺度的多次干湿变化,特别是在146.96 ka BP前后、141.98 ka BP左右和107.06 kaBP前后发生过重大转变;相应地,沙地地表植被也经历了干冷多风条件下的干草原、荒漠草原和温暖湿润或温凉稍湿气候条件下的森林草原、疏林草原的多次变化。科尔沁沙地古气候的干湿变化可能是晚第四纪东亚冬、夏季风强弱变化的反映。Horqin sandy land, located at the transitional region between the Northeastern plain and the Mongolia Plateau, is sensitive to climate changes. In this paper, Optical stimulated luminescence dating （OSL） has been used to obtain ages of the typical profile. Combining with the sedimentary facieses, magnetic susceptibility, organic content and grain size, which can be employed as proxy indicators of the paleoclimate and paleoenvironment changes, it is suggested that climate of the sandy land has been changed with dry and wet at 103 ~10~ time scale, especially at approximately 146.96 ka BP, 141.98 ka BP and 107.06 ka BP, the paleoclimate and paleoenvironment have significantly shifted. Accordingly, the vegetation in this area has undergone a succession of dry-cold grassland, desert grassland and warm-moist or milder-humid forest grassland, sparse grassland. The changes of the climate in Horqin sandy land are consistent with variations of the East Asian monsoon during late Quaternary.

关 键 词：光释光测年 晚第四纪 科尔沁沙地 干湿变化 

分 类 号：P532[天文地球—古生物学与地层学]