末次间冰期以来中国黄土记录的地磁漂移研究回顾  

Review of geomagnetic excursions since the last interglacial recorded in the Chinese loess

作　　者：刘佑堂 秦华峰[1,2,3] LIU YouTang;QIN HuaFeng(State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Academy of Sciences,Beijing 100029,China;Institution of Earth Science,Chinese Academy of Science,Beijing 100029,China;University of Chinese Academy of Science,Beijing 100049,China)

机构地区：[1]中国科学院地质与地球物理研究所岩石圈演化国家重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学,北京100049

出　　处：《地球物理学进展》2021年第4期1412-1419,共8页Progress in Geophysics

基　　金：国家自然科学基金项目(41674073)资助。

摘　　要：记录在第四纪沉积物或火山岩中的地磁漂移不仅加深了人们对地球动力学机制的认识,还为古环境和古生物研究提供了重要的时间控制点.中国黄土高原地区广泛分布的第四纪黄土-古土壤序列粒度细、沉积速率高且连续性好,是记录地磁漂移的良好材料.本文重点总结和分析了前人对末次间冰期以来中国黄土中地磁漂移的研究结果,主要包括Blake、Laschamp和Mono Lake.结果显示,部分黄土剖面可以记录地磁漂移的地磁场变化细节特征,但并非所有剖面都能记录全部已知的地磁漂移,且同一地磁漂移在不同剖面所呈现的地磁场形态学特征也存在差异.在地磁漂移期间,地磁场稳定性较差、黄土沉积中千年-百年尺度的沉积间断以及黄土沉积后的成岩作用影响可能是造成地磁漂移特征记录差异或缺失的客观原因.以前的研究中,样品时间窗选择过大带来的平滑效应可能是重要的人为因素.本文认为,将来的研究中,根据10Be产率的变化,并结合高密度光释光定年,进行更高分辨率(如10~100年尺度)的古地磁研究,可能有利于揭示黄土记录的地磁漂移信息.The geomagnetic excursions recorded in the quaternary sediments or volcanic rocks not only enhanced our understanding of the geodynamics,but also provided important age constraints for the paleoenvironment and paleontology.The widely distributed quaternary loess-paleosol sequences in Chinese Loess Plateau have fine-grained particles,high deposition rate and good continuity,which were ideal materials for recording geomagnetic excursion.We summarized and analyzed the previous findings about geomagnetic excursions since the last interglacial,mainly including Blake,Laschamp and Mono Lake.The results showed that the detailed morphology of geomagnetic excursion can be recorded in the loess,but not all sections.Meanwhile,the discrepancy of different sections corelated with the same excursion was evident.The reasons were attributed to poor stability of the earth’s magnetic field during the period of geomagnetic excursion,the 100~1000 year scale discontinuity and the post depositional diagenesis influence.In previous studies,too large time window of sample which caused smoothing may be important factors.We suggest that,in the future,integrating the 10Be flux with high-resolution paleomagnetic study(such as 10~100 year scale)and Optically Stimulated Luminescence(OSL)dating,may be beneficial to reveal geomagnetic excursions recorded in the Chinese loess.

关 键 词：末次间冰期 中国黄土 地磁漂移 

分 类 号：P318[天文地球—固体地球物理学] P352[天文地球—地球物理学]