福建海坛岛老红砂环境磁学特征及其古气候意义  

Environmental magnetism characteristics and paleoclimatic significance of the old red sandy sediment in Haitan Island of Fujian

作　　者：王浩[1,2] 李志忠[1,3] 田明中[2] 

机构地区：[1]福建师范大学地理科学学院,福州350007 [2]中国地质大学地球科学与资源学院,北京100083 [3]中国科学院地球环境研究所黄土与第四纪国家重点实验室,西安710075

出　　处：《干旱区资源与环境》2013年第11期122-128,共7页Journal of Arid Land Resources and Environment

基　　金：国家自然科学基金项目(批准号:41271031);中国科学院黄土与第四纪地质国家重点实验室开放基金项目(批准号:SKLLQG1113)资助

摘　　要：以福建海坛岛青峰剖面(QF)老红砂为研究对象,系统测定剖面磁学参数,并与粒度组分进行比对,以此揭示研究区老红砂磁学特征、阶段性变化规律及其所记录的古气候信息。结果表明:1)在QF剖面上,磁学参数随着深度起伏波动,低频磁化率(χlf)、高频磁化率(χhf)、饱和等温剩磁(SIRM)和"软"剩磁(SoftIRM)的变化趋势基本一致,频率磁化率(χfd)、"硬"剩磁(Hard IRM)、退磁系数(S-100mT)和磁化系数(F300mT)在均值附近小幅变化;2)假单畴(PSD)、多畴(MD)的亚铁磁性矿物是剖面磁性的主要贡献者;3)χlf和χfd阶段性变化,反映了QF剖面老红砂沉积和风化成土作用经历了暖湿-较暖湿-冷干-较冷干-极冷干-暖湿的气候波动变化过程。The study focused on the old red sandy sediment in the profile of Haitan Island which is located in Fujian,gave a systematic determination of some magnetism parameters and made a comparison with the grain-size distribution.The study revealed the significance of environmental magnetism characteristics of the red sandy sediment,the phasic variation and the paleoclimate within its record.The results are as follows： 1） The magnetism parameters vary with the change of the depth in QF profile： low-frequency magnetic susceptibility（χlf）,high frequency magnetic susceptibility（χhf）,saturation isothermal remnant magnetization（SIRM） and soft isothermal remnant magnetization（Soft IRM） have a similar tend while frequency dependent susceptibility（χfd）,hard isothermal remanent magnetization（Hard IRM）,S-100mT and F300mT fluctuate around the mean value.2） Those ferromagnetic minerals in pseudo single domain（PSD）,multidomain（MD） are the main contributors to the magnetism of the old red sandy sediment.3） The phasic variations of χlf and χfd reveal the fact the sedimentations of the old red sandy sediment in QF profile and the weathering pedogenesis may have gone through the climatic cycle from being warm-wetness,a little warm-wetness,cold and dry,colder and drier,the coldest and driest,and warm-wetness.

关 键 词：老红砂 环境磁学 古气候 福建海坛岛 

分 类 号：P574.19[天文地球—矿物学]