|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
rodo
1
1 Institute of Geological Sciences, Polish Academy of Sciences, Senacka 1, 31-002 Kraków, Poland
2 US Geological Survey, Suite E-127, 3215 Marine St., Boulder, Colorado 80303-1066, USA
3 Science du Sol INRA, Versailles, France
4 Department of Mineral Deposits, Comenius University, Bratislava, Slovakia
* E-mail address of corresponding author: nddudek{at}cyf-kr.edu.pl
Two independent methods of crystal-size distribution analysis were compared: the Bertaut-Warren-Averbach XRD technique (MudMaster computer program) and high-resolution transmission electron microscopy (HRTEM). These techniques were used to measure thickness distributions of illite crystals (fundamental particles) from sets of illite-smectites from shales and bentonites that had expandabilities ranging from 86%S to 6%S. The illite-smectites were treated with a polymer (polyvinylopyrolidone, PVP) to separate them into fundamental particles for XRD and HRTEM investigations.
A systematic difference between XRD and HRTEM results was observed: XRD (area-weighted distributions) detected a larger fraction of thick (>4 nm) and a smaller fraction of thin crystals as compared to HRTEM (number-weighted distributions). As a result, XRD-determined distributions have larger mean thickness values and larger distribution parameters (
and ß2). The measurements performed by the two techniques were verified by modeling XRD patterns of the PVP-illites, using the measured distributions as inputs. The modeling indicated that the XRD-determined distributions are very accurate. Selecting broader thickness distributions in MudMaster further improved the modeling results. The HRTEM measurements underestimate the proportion of coarse particles, in particular in shale samples, and this inaccuracy is attributed to the effect of using number-weighted (rather than area-weighted) distributions and to inaccurate counting statistics for thick crystals.
Key Words: BWA Analysis • Crystal Size Distribution • Fundamental Particles • HRTEM • Illite-smectite • Lognormal Distribution • MudMaster • XRD
This article has been cited by other articles:
|
|
 |
|
  J. A. Caulfield, T. A. Wells, and K. E. Miller NOVEL METHOD FOR TRANSMISSION INFRARED ANALYSIS OF CLAY MINERALS USING SILICON WAFER SUBSTRATES Clays and Clay Minerals, April 1, 2007; 55(2): 213 - 219. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Honty, M. Honty, P. Uhlik, V. Sucha, M. Caplovicova, J. Francu, N. Clauer, and A. Biron SMECTITE-TO-ILLITE ALTERATION IN SALT-BEARING BENTONITES (THE EAST SLOVAK BASIN) Clays and Clay Minerals, October 1, 2004; 52(5): 533 - 551. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. E. Blum, A. E. Blum, and D. D. Eberl MEASUREMENT OF CLAY SURFACE AREAS BY POLYVINYLPYRROLIDONE (PVP) SORPTION AND ITS USE FOR QUANTIFYING ILLITE AND SMECTITE ABUNDANCE Clays and Clay Minerals, October 1, 2004; 52(5): 589 - 602. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. A. Drits and V. A. DRITS Structural and chemical heterogeneity of layer silicates and clay minerals Clay Minerals, December 1, 2003; 38(4): 403 - 432. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Dudek, T. Dudek, and J. Srodon THICKNESS DISTRIBUTION OF ILLITE CRYSTALS IN SHALES. II: ORIGIN OF THE DISTRIBUTION AND THE MECHANISM OF SMECTITE ILLITIZATION IN SHALES Clays and Clay Minerals, October 1, 2003; 51(5): 529 - 542. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Shang, C. Shang, J. A. Rice, D. D. Eberl, and J.-S. Lin MEASUREMENT OF ILLITE PARTICLE THICKNESS USING A DIRECT FOURIER TRANSFORM OF SMALL-ANGLE X-RAY SCATTERING DATA Clays and Clay Minerals, June 1, 2003; 51(3): 293 - 300. [Abstract] [Full Text] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
