金云母-蛭石间层矿物分晶层晶体化学式的计算及意义  

The calculation and significance of individual crystal layer chemical formula of phlogopite-vermiculite interstratified mineral

作　　者：刘福生[1] 彭同江[1] 

机构地区：[1]西南科技大学矿物材料及应用研究所,绵阳621002

出　　处：《岩石学报》2002年第2期238-246,共9页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(项目编号:40102006)

摘　　要：金云母—蛭石间层矿物由金云母晶层与蛭石晶层交叠排列而成,采用一般计算方法得出的晶体化学式不能充分揭示结构中金云母晶层与蛭石晶层各自的晶体化学特征。本文以化学成分分析与阳离子交换容量为基础,假定可交换性阳离子均为蛭石晶层层间阳离子,非交换性阳离子为金云母晶层层间阳离子,金云母晶层与蛭石晶层具有相同的八面体层等,计算出了结构中两种晶层的分晶层晶体化学式,确定了结构中两种晶层的比例和蛭石晶层的层电荷数。并在此基础上讨论了新疆尉犁蛭名矿金云母与金云母-蛭石间层矿物的晶体化学特征。结果表明该方法设计合理,符合晶体化学原理,所计算的数据可靠。利用该方法计算出的两种晶层的比例为金云母-蛭石1:1规则间层矿物的确定提供了必要的依据。也为其它类似间层矿物的研究提供了一种计算分晶层晶体化学式的可行方法。Phlogopite-vermiculite interstratified mineral is composed of phlogopite crystal layer and vermiculite layer. Crystal chemical formula computed with normal method can not reveal the real crystal chemical characters of phlogopite and vermiculite crystal layer in the interstratified structure. Based on results of chemical composition analysis and cations exchange capacity, and presupposition that changeable cations belong to the vermiculite layer, while the unchangeable cations belong to the phlogopite layer. The two crystal layer have same octahedron cations. We calculated out the individual crystal layer chemical formula of phlogopite-vermiculite interstratified mineral, the proportions of the two crystal layers in the interstratified structure, and the layer charge of vermiculite crystal layer 0. 607 similar to 0. 896; we also discussed the crystal chemical characters of phlogopite-vermiculite interstratified minerals from Weli Xinjiang vermiculite mine. The results of this paper reveal that this method of individual crystal layer chemical formula calculation is reliable for phlogopite-vermiculite interstratified mineral, the proportion of phlogopite and vermiculite crystal layer is a necessary evidence to confirm phlogopite-vermiculite 1 : 1 regular interstratified mineral. The method also can be used on studying other analogous types of interstratified minerals.

关 键 词：分晶层晶体化学式 金云母-蛭石间层矿物 金云母 新疆 

分 类 号：P578.959[天文地球—矿物学] P578.963[天文地球—地质学]