New insights into the formation of diagenetic illite from TEM studies

doi:10.2138/am.2013.4220

CORC > 北京大学 > 地球与空间科学学院

	New insights into the formation of diagenetic illite from TEM studies
	Chen, Tao ; Wang, Hejing ; Li, Ting ; Zheng, Nan
刊名	american mineralogist
	2013
关键词	Diagenetic illite heterogeneous nucleation 1M(d) polymorph edge dislocation screw dislocation TRANSMISSION ELECTRON-MICROSCOPY SMECTITE ILLITIZATION REACTION-MECHANISMS LAYER SILICATES MICA POLYTYPES PELITIC ROCKS PHYLLOSILICATES MICROSTRUCTURES CRYSTALLINITY TRANSITION
DOI	10.2138/am.2013.4220
英文摘要	Diagenetic illite from the Proterozoic Chuanlinggou Formation, China, has been investigated using the techniques of transmission electron microscopy (TEM), selected-area electron diffraction (SAED), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectrometer (EDS). Polytypes of 1 M-d and 1M illite coexist in the diagenetic illite. The 1 M-d polymorph is predominant in the <0.2 mu m size fraction, which has high Al and low Mg contents and irregular crystal shapes. Lattice-fringe imaging and one-dimensional structural imaging show abundant structure defects. The 1M(d) illite has both layer and sheet terminations caused by edge dislocations and layer displacements along c* caused by screw dislocations. These observations indicate that the disordered 1 M-d structure of the diagenetic illite resulted from abundant dislocations. The dislocation serves as nucleation sites for the illite nano particles to spontaneously nucleate in the initial stage of illite formation. Such a nucleation process obeys the Ostwald ripening rule. The illite only shows a 1.0 nm thickness for each layer in high-resolution TEM images, which suggests that the illite crystals have no mixed smectite layer, and the 1 M-d illites are authigenic and not illitized from smectite or illite/smectite. Heterogeneous nucleation led to directly crystallization of the 1 M-d illite during the initial growth of illite in shale under a low-temperature and tectonic-stress-free environment. The results have implications for interpreting the distribution of 1 M-d illite in sedimentary rocks.; Geochemistry & Geophysics; Mineralogy; SCI(E); 1; ARTICLE; 5-6; 879-887; 98
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/391714]
专题	地球与空间科学学院
推荐引用方式 GB/T 7714	Chen, Tao,Wang, Hejing,Li, Ting,et al. New insights into the formation of diagenetic illite from TEM studies[J]. american mineralogist,2013.
APA	Chen, Tao,Wang, Hejing,Li, Ting,&Zheng, Nan.(2013).New insights into the formation of diagenetic illite from TEM studies.american mineralogist.
MLA	Chen, Tao,et al."New insights into the formation of diagenetic illite from TEM studies".american mineralogist (2013).