Microstructure characteristics of illite from Chuanlinggou Formation of Changcheng System in Jixian County, Tianjin City

作     者：CHEN Tao1,2 & WANG HeJing2? 1 Institute of Gemology, China University of Geosciences, Wuhan 430074, China 2 School of Earth and Space Sciences, Peking University, Beijing 100871, China 

作者机构：Institute of Gemology China University of Geosciences Wuhan China School of Earth and Space Sciences Peking University Beijing China 

出 版 物：《Science China Earth Sciences》 (中国科学（地球科学英文版）)

年 卷 期：2007年第50卷第10期

页      面：1452-1458页

核心收录：

学科分类：070801[理学-固体地球物理学] 07[理学] 0708[理学-地球物理学] 

基　　金：Fourth Research Foundation for Outstanding Young Teachers, China University of Geosciences (Wuhan) National Natural Science Founda-tion of China (Grant Nos. 40272022 and 40572032) 

主　　题：Jixian illite, microstructure, high-resolution transmission electron microscopy (HRTEM), one-dimensional lattice images, two-dimensional lattice images 

摘      要：The microstructure charateristics of illite from the Chuanlinggou Formation of Changcheng System (Chch) in Jixian County, Tianjin City has been studied by means of high-resolution transmission electron microscopy (HRTEM), selected-area electron diffraction (SAED), X-ray energy dispersive spectrum (EDS) and X-ray powder diffraction (XRD). The Kuebler index of illite crystallinity is 0.505° Δ2θ, which indicates that the host rock is in a middle diagenetic stage. The chemical analyses of EDS for illite studied indicate a heavily absent in interlayer cation and an average chemical formula of K_(0.57)(AI_(1.80)Mg_(0.42)(Fe^(2+))_(0.12))_(∑=2.34)(Si_(2.92)Al_(1.80))_(∑=4)O_(10)(OH)_2. It is found, from one-dimensional lattice images, that the layers of illite not only stack in a flat way but also in a curving way. A matting fabric illite structure results from stacking faults. Combined with SAED analysis the illite studied can be affirmed as 1M illite. The two-dimensional lattice images are obtained from [100] and [110] incidences, whose lattice images have the same d-values but different intersecting angles. The two-dimensional lattice image with [100] incidence is orthogonal to each other, whilst that with [110] incidence is oblique. This paper provides some important structure information of authigenic clay minerals for the well-known mesoproterozoic section of Jixian County.