中太平洋海山富钴结壳中水羟锰矿的超结构  

Super Structure of Vernadite in Co-Rich Manganese Crusts from the Middle Pacific Seamounts

作　　者：叶瑛[1] 韩杰[1] 邬黛黛[1] 陈雪刚[1] 沈忠悦[1] 王步清[2] 

机构地区：[1]浙江大学地球科学系,杭州310027 [2]塔里木油田勘探开发研究院,新疆库尔勒市841000

出　　处：《地质学报》2007年第6期814-819,共6页Acta Geologica Sinica

基　　金：国家"十五"大洋专项基金项目(编号DY105-01-04-3)资助的成果

摘　　要：采自中太平洋海山富钴结壳主要由水羟锰矿组成,在XRD衍射图谱上,该矿物缺少(001)和(002)底面衍射,其原因是水羟锰矿包含了两种对称型的八面体层,即三斜对称和六方对称的八面体层,它们沿c轴方向无序排列。部分样品中的水羟锰矿在低角度区具有d>2.0nm的超结构衍射峰,它在实质上反映了矿物结构层的长程有序性,即两种层片的排列具有某种周期性或规律性。部分样品原先没有,但在加热后出现超结构衍射峰,可能是因为样品在空气中加热,使三斜层片中的Mn(III)被氧化成Mn(IV),从而转变为六方层片,继而改变了水羟锰矿的有序性。富钴结壳中水羟锰矿的超结构,在一定程度上反映了矿物形成环境的变化。Co-rich manganese crusts from the Middle Pacific Seamounts are composed mainly of vernadite which is in short of （001） and （002） basal spacing, for the reason that in its crystal structure there are two sorts of octahedral sheets, i. e. , triclinic and hexagonal sheets, stacking together along c axis without ordering. Super structure defraction in low-angle area with a d value〉2.0 nm is found in some samples. This is quite possibly related with certain kind of long-range ordering in vernadite, indicating periodical or regular arrangement of sheets with different symmetry. For the samples without super structure defraction, the peak appears after being heated in 110℃ for 12 h. While heated in air, Mn （Ⅲ） in triclinic sheet could be oxidized into Mn （Ⅳ）. This may change the symmetry of the sheet and then the ordering of vernadite. It is believed that the super structure of vernadite is an indicator of its formation environment.

关 键 词：超结构 水羟锰矿 富钴结壳 中太平洋海山 

分 类 号：P744[天文地球—海洋科学]