布容-松山极性倒转事件的海陆地质记录及其不同步性探讨  

Brunhes-Matuyama Polarity Reversal Records and Discussion on Its Recording Phase Lag between Ocean and Terrestrial Sediment

作　　者：孔祥辉[1,2,3] 周卫健[1,2] 鲜锋[1,2] 武振坤[1,2] 

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,陕西西安710075 [2]西安加速器质谱中心,陕西西安710061 [3]中国科学院大学,北京100049

出　　处：《地球科学进展》2012年第9期937-946,共10页Advances in Earth Science

基　　金：国家自然科学基金项目“最近2.1万年气候快速变化的综合地质记录及时空对比研究”(编号:41023006);中国科学院国家外国专家局创新团队国际伙伴计划“亚洲季风-干旱环境演化中的突变事件、环境效应及机理”(编号:KZZD-EW-TZ-03);黄土与第四纪地质国家重点实验室开放基金项目“黄土10Be样品野外采集及古气候代用指标的测试”(编号:SKLLQG07015)资助

摘　　要：布容—松山(B/M)极性倒转事件是第四纪发生的最近一次地磁极性倒转,研究地磁极性倒转的特征不仅对理解地磁场演化规律具有重要意义,同时极性倒转通常具有全球等时性,因此常被视为地层划分和全球气候对比的关键时间标记物。然而古地磁研究表明,布容—松山事件在海洋与中国黄土沉积物中的记录存在着"错位"现象,使得基于磁性地层年代框架下的中国黄土—古土壤序列与全球气候记录之间的对比存在不确定性。基于这一问题,重点回顾了B/M倒转事件在海洋与中国黄土沉积物中的研究历史及现状,总结分析了已有对该事件在海陆沉积记录中的"错位"现象不同解释之间的差异;此外,还介绍了最近几年利用中国黄土中的宇宙成因核素10Be记录示踪地磁场变化的新进展,进一步探讨了利用10Be示踪结合古地磁分析手段解决中国黄土中B/M事件记录与海洋沉积物存在"错位"现象的可能性。The Brunhes-Matuyama （B/M） reversal is the most recent happened geomagnetic polarity reversal since the Quaternary period. The polarity reversal is considered as occurring synchronously around the world and so is a key time marker which can be used to divide the stratigraphie sequences and correlating climatic proxies between different sediments. It is also very important for understanding the variation in the geomagnetic field. However, the paleomagnetic studies have revealed that the records of B/M reversal in Chinese loess-paleosol and the marine sediments are not synchronous, there is an time/climatic ＂offset＂ between these two sediments. The ＂offset＂ both leads to a challenge for the certainties of correlation between Chinese loess-paleosol sequences and the global climate records based on the paleomagnetic time scale. To discuss this ＂offset＂ question, this paper intends to review the study history and recent progress on the B/M reversal event in marine and Chinese loess sediments, and to evaluate the possible explanations of this ＂offset＂ phenomenon. In addition, the paper also introduces the recent progress of paleogeomagnetie field variation studies traced by cosmogenic nuclide 10Be in Chinese loess, suggesting the feasibility of combining the 10Be with paleomagnetic analysis to trace the exact position of B/M event recorded in Chinese loess.

关 键 词：B/M倒转事件 时间标记物 第四纪 地磁场 宇宙成因核素10Be 

分 类 号：P318.44[天文地球—固体地球物理学]