X-Ray Powder Diffraction Identification of Illitic Materials

Abstract

Abstract--The 10-/~ clay components of sedimentary rocks ("iUites") are commonly mixtures of 100% nonexpandable illite and an ordered illite/smectite mixed-layer mineral. If the proportion of the illite/ smectite in a mixture is sufficient to produce a measurable reflection between 33-35*20 (CuKa radiation) that is noncoincident with an illite reflection, the ratio of component layers and type of interstratification for the mixed-layer mineral can be determined. The identification technique developed in this study rests upon the following experimental findings for ordered illite/smectites of diagenetic origin: (1) the thickness of the illite layer in illite/smectites is 9.97/~; (2) the thickness of smectite-ethylene glycol complex ranges from 16.7 to 16.9/~; (3) illite/smectites form a continuous sequence ofinterstratification types--random, random/IS, IS, IS/ISII, ISII--and each type is related to a specific range of expandability.The new technique broadens the computer simulation method developed by R. C. Reynolds and J. Hower to include those sedimentary materials which are dominated by the presence of discrete illite, are low in illite/smectite, and, as such, have been described previously only by an "illite crystallinity index."

Diagenesis to very low-grade metamorphism in lower Palaeozoic sediments: A case study from deep borehole Tobolka 1, the Barrandian Basin, Czech Republic

“…The smectite content (often referred to as "expandability") in IS is generally acknowledged as a geothermometer for the diagenetic zone (Pollastro, 1993;Sachsenhofer et al, 1998;Środoń, 1984;Środoń and Eberl, 1984). Though this approach has been later challenged by some studies in orogenic settings (e.g.…”

Occurrence of an Environmental Acinetobacter baumannii Strain Similar to a Clinical Isolate in Paleosol from Croatia

“…The identification of clay minerals was generally based on the methods outlined by Brown (12), Brindley and Brown (13), and Moore and Reynolds (14). The term "illitic material" is used as defined by Ś rodoń (15) and Ś rodoń and Eberl (16). The thin section was prepared in the Thomas Beckmann Laboratory (Schwülper-Lagesbüttel, Germany) and was analyzed using a Leica DM-LSP petrographic microscope with plane-polarized light (ppl) and cross-polarized light (xpl).…”

Low‐grade metamorphism in the Palaeozoic sequences of the Townsville hinterland, northeastern Australia*

“…Evolution of the illitic material ( sensu Środoń 1984) has been widely used to assess the evolution of pelitic material during diagenesis and low‐grade metamorphism (Eberl et al . 1998; Brime 1999; Środoń et al .…”