A Technique for Maintaining Texture and Permanent Expansion of Smectite Interlayers for TEM Observations

Jin-Wook Kim
1995 Clays and clay minerals  
A process for treating smectite-bearing rock samples that utilizes LR White resin; allows TEM observation of expanded smectite interlayers and therefore preservation of original rock textures. Examples of several lattice fringe images are shown, including: (1) Dioctahedral smectite layers from a shale (1388.9 meter depth, Texas Gulf Coast) give fringes that consistently have spacings of 1.2-1.3 nm, yet duplicate other features previously observed in collapsed samples. (2) Packets of illite
more » ... kets of illite layers give fringes with 1.0nm spacings coexisting with packets of (dominantly) R1 US having 2. l-nm lattice fringe spacings in a Gulf Coast shale from 4742.1 m. (3) Rectorite from Garland Co., Arkansas gives 2.3-nm lattice fringes. Samples with wide ranges of I/S ratios and lithologies have been found to be permanently expanded with retention of original textures, commonly leading to unambiguous identification of illite and smectite interlayers in lattice fringe images.
doi:10.1346/ccmn.1995.0430106 fatcat:cflmfn3dc5cl5fjpjrmjwm527e