%0 Journal Article
%T Quantification of magnetic coercivity components reveals the cause of anomalous decrease of magnetic susceptibility of the Xiashu loess<br>矫顽力组分定量分析揭示下蜀黄土磁化率异常降低的原因
%A HAN Zhi-Yong
%A LI Xu-Sheng
%A CHEN Ying-Yong
%A YANG Da-Yuan
%A <br>韩志勇
%A 李徐生
%A 陈英勇
%A 杨达源
%J 地球物理学报
%D 2008
%I 
%X The magnetic susceptibility of the Xiashu loess of several layers in Dagang section in Zhenjiang anomalously decreases,which results in a poor correlation of the susceptibility record with its counterpart in North China.In order to explore the cause of the anomalous decrease,we drilled the ZK core in Dagang.Ten representative samples are collected from different depths and their isothermal remanent magnetization acquisition curves are measured.Quantification of magnetic coercivity components is carried out by using the program(Irmunmix V2.2) that uses the expectation-maximization algorithm.The results show that these ten samples can be divided into three groups.The first group contains no moderate magnetic coercivity component;the second group only contains a few moderate magnetic coercivity components;the third group contains many moderate magnetic coercivity components.The content of magnetic coercivity components is closely related to the content of the ferromanganese concretion.More ferromanganese concretions the sample contains,fewer soft magnetic coercivity components and more moderate and hard magnetic coercivity components the sample contains.Correspondingly,the sample of this kind has a low magnetic susceptibility.The magnetic coercivity component analysis indicates that the soft magnetic coercivity components were dissolved and new moderate and hard magnetic coercivity components were precipitated during the formation process of the ferromanganese concretion.This secondary process leads to the anomalous decrease of the magnetic susceptibility.The sample containing more ferromanganese concretions underwent stronger reducing action.Therefore,we conclude that the anomalous decrease of the magnetic susceptibility is the result of the reducing action,which might be the production within a period of enhanced precipitation.
%K IRM<br>下蜀黄土
%K 矫顽力组分
%K 铁锰结核
%K 磁化率
%K 还原作用
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=1E44AE713D8A6DE0&jid=14DC41C59CBF6770055A7D610D53AE46&aid=05F3570059A8CDE41FF61F5074FB39F6&yid=67289AFF6305E306&vid=987EDA49D8A7A635&iid=B31275AF3241DB2D&sid=FBF1CFC71FDCE0E5&eid=1AA24020BCD2D13D&journal_id=0001-5733&journal_name=地球物理学报&referenced_num=1&reference_num=28