伊利石结晶度及其在低温变质研究中若干问题的讨论

文中介绍与伊利石结晶度相关的伊利石矿物新的定名方案;讨论了伊利石结晶度的结晶学基础与Scherrer方程式的关系;讨论了三个重要的伊利石结晶度指数Weaver、K櫣bler和Weber指数的关系,并介绍推导的Weaver、K櫣bler和Weber指数的理论关系式;评价了衍射仪测量条件对结晶度数值的影响和三套伊利石结晶度标样的作用以及成岩带、变质带与葡萄石-绿纤石相、沸石相、绿纤石-阳起石亚相对比的依据。建议(1)停用绢云母一词;(2)建立可供各实验室使用的具有晶体结构和晶体化学参数和多型参数的伊利石结晶度标样;(3)建议多开展规范的可进行国际对比的低温变质研究,划分出与国际上一致的成岩带和近变质带,不仅利于低温变质作用理论的研究,而且由于成岩带到近变质转变带是重要的煤气油的生成带,也利于中国煤气油资源的勘探与开发,利于国民经济的长远持续发展。

Some aspects of illite crystallinity and its applications in low temperature metamorphism

This paper introduces the new “Nomenclature” of mica and the position of illite in the new nomenclature and discusses (i) the crystallographic basis of illite crystallinity and the relationship between illite crystallinity and the Scherrer equation and (ii) the relationships between the Weaver, Kübler and Weber indices and introduces the theoretical deduction of their relationships.It is also reviewed in this paper that the impact on illite crystallinity from measuring conditions and the role of three illite crystallinity sets.These data by which the diagenetic zone, anchizone and epizone are classified are reviewed in the point of view of metamorphic grade of pumpellyite-prehnite facies and zeolite facies as well as pumpellyite-actinolite subfacies.It is suggested that (a) to stop use the term “sericite”, (b) to establish a new illite crystallinity set that is of such data like crystal structure and crystal chemistry, unit cell, space group, polytype, chemical formula etc., (c) to do more international comparable investigation on low temperature metamorphism around China and that will be not only benefit to the metamorphism study but also to the economic development of China since the diagenetic zone and the transition belt between diagenitic zone and anchizone are the segments of the formation of petroleum, gas and coal.