Semiquantitative determination of trans-vacant and cis-vacant 2:1 layers in illites and illite-smectites by thermal analysis and X-ray diffraction

Abstract

Other| December 01, 1998 Semiquantitative determination of trans-vacant and cis-vacant 2:1 layers in illites and illite-smectites by thermal analysis and X-ray diffraction Victor A. Drits; Victor A. Drits Russian Academy of Sciences, Institute of Geology, Moscow, Russian Federation Search for other works by this author on: GSW Google Scholar Holger Lindgreen; Holger Lindgreen Search for other works by this author on: GSW Google Scholar Alfred L. Salyn; Alfred L. Salyn Search for other works by this author on: GSW Google Scholar Robert Ylagan; Robert Ylagan Search for other works by this author on: GSW Google Scholar Douglas K. McCarty Douglas K. McCarty Search for other works by this author on: GSW Google Scholar American Mineralogist (1998) 83 (11-12_Part_1): 1188–1198. https://doi.org/10.2138/am-1998-11-1207 Article history first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Victor A. Drits, Holger Lindgreen, Alfred L. Salyn, Robert Ylagan, Douglas K. McCarty; Semiquantitative determination of trans-vacant and cis-vacant 2:1 layers in illites and illite-smectites by thermal analysis and X-ray diffraction. American Mineralogist 1998;; 83 (11-12_Part_1): 1188–1198. doi: https://doi.org/10.2138/am-1998-11-1207 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyAmerican Mineralogist Search Advanced Search Abstract Interstratified illite-smectites (I/S) and illite-smectite-vermiculites (ISV) representing both hydrothermal and diagenetic transformations and having different degrees of structural order were investigated for cis-trans occupancy in the octahedral sheet by X-ray diffraction (XRD) and by differential thermal analysis (DTA) in combination with evolved water analysis (EWA) using an infrared detector. By XRD, the amounts of cis (W cv ) and trans (W tv ) vacant 2:1 layers were determined for the three-dimensionally ordered samples using both the WILDFIRE simulation program and calculations based on positions of the 11l and 11l reflections. Based on the EWA curves, the I/S and ISV could be divided into three groups having (1) one strong and one or more weak EWA peaks; (2) two well-resolved peaks; and (3) a complex EWA curve. The amounts of cis- and trans-vacant sites were determined by peak fitting of the total dehydroxylation curve. The complex EWA curves were, however, in addition split into separate dehydroxylation processes during a step-heating technique. If the EWA peaks below and above 600 degrees C were attributed to trans vacant (tv) and cis vacant (cv) octahedra, respectively, the W cv values determined by XRD and by EWA were in agreement. For the three-dimensionally ordered minerals, both XRD and EWA should be used, whereas the EWA method can be applied to the structurally disordered samples having no diagnostic 11l reflections. Accordingly, a combination of XRD and EWA for the determination of W cv and W tv supports an evaluation of the mechanism of illitization in various geological environments. Thus, significant changes in W cv and W tv during illitization are likely due to a dissolution-precipitation, whereas almost constant values indicate a solid-state transformation. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.