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Quantification of stacking disordered Si–Al layer silicates by the Rietveld method: application to exploration for high-sulphidation epithermal gold deposits

Published online by Cambridge University Press:  22 April 2015

Kristian Ufer*
Affiliation:
Federal Institute for Geosciences and Natural Resources, Geozentrum Hannover, Stilleweg 2, 30655 Hannover, Germany
Reinhard Kleeberg
Affiliation:
Institute of Mineralogy, Brennhausgasse 14, TU Bergakademie Freiberg, 09599 Freiberg, Germany
Thomas Monecke
Affiliation:
Department of Geology and Geological Engineering, Colorado School of Mines, 1516 Illinois Street, Golden 80401, Colorado
*
a) Author to whom correspondence should be addressed. Electronic mail: [email protected]

Abstract

Hydrothermally altered rocks hosting precious metal deposits frequently contain stacking disordered layer silicates. X-ray diffraction analysis using the Rietveld method can be used to determine mineral abundances in these rocks if suitable disorder models are applied. It is shown here that disorder models of kaolinite and pyrophyllite can be described by a recursive calculation of structure factors. This permits the physically sound refinement of real structure parameters of these disordered minerals and the determination of mineral abundances. Even mixtures containing two disordered Si–Al layer silicates can be quantified reliably. The developed disorder models can now be implemented in routine phase analysis, allowing the quantification of large numbers of samples to identify mineralogical gradients surrounding ore deposits.

Type
Technical Articles
Copyright
Copyright © International Centre for Diffraction Data 2015 

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References

Bergmann, J., Friedel, P. and Kleeberg, R. (1998). “BGMN – a new fundamental parameters based Rietveld program for laboratory X-ray sources, its use in quantitative analysis and structure investigations,” CPD Newsl. (Commission of Powder Diffraction, International Union of Crystallography) 20, 58.Google Scholar
Bergmann, J., Monecke, T. and Kleeberg, R. (2001). “Alternative algorithm for the correction of preferred orientation in Rietveld analysis,” J.Appl. Crystallogr. 34(1), 1619.CrossRefGoogle Scholar
Bish, D. L. and Von Dreele, R. B. (1989). “Rietveld refinement of non-hydrogen atomic positions in kaolinite,” Clays Clay Miner. 37(4), 289296.Google Scholar
Bookin, A. S., Drits, V. A., Plançon, A. and Tchoubar, C. (1989). “Stacking faults in kaolin-group minerals in the light of real structural features,” Clays Clay Miner. 37(4), 297307.Google Scholar
Cheary, R. W. and Coelho, A. (1992). “Fundamental parameters approach to X-ray line-profile fitting,” J. Appl. Crystallogr. 25(2), 109121.Google Scholar
Chipera, S. J. and Bish, D. L. (2001). “Baseline studies of the Clay Minerals Society source clays: powder X-ray diffraction analyses,” Clays Clay Miner. 49(5), 398409.Google Scholar
Drits, V. A. and Tchoubar, C. (1990). X-ray Diffraction by Disordered Lamellar Structures (Springer-Verlag, Berlin, Heidelberg).Google Scholar
Hill, R. J., Tsambourakis, G. and Madsen, I. C. (1993). “Improved petrological modal analyses from X-ray powder diffraction data by use of the Rietveld method I. Selected igneous, volcanic, and metamorphic rocks,” J. Petrol. 34(5), 867900.Google Scholar
Kogure, T., Jige, M., Kameda, J., Yamagishi, A., Miyawaki, R. and Kitagawa, R. (2006). “Stacking structures in pyrophyllite revealed by high-resolution transmission electron microscopy (HRTEM),” Am. Mineral. 91(8–9), 12931299.Google Scholar
Lee, J. H. and Guggenheim, S. (1981). “Single crystal X-ray refinement of pyrophyllite-1Tc,” Am. Mineral. 66(3–4), 350357.Google Scholar
Monecke, T., Köhler, S., Kleeberg, R., Herzig, P. M. and Gemmell, J. B. (2001). “Quantitative phase-analysis by the Rietveld method using X-ray powder-diffraction data: Application to the study of alteration halos associated with volcanic-rock-hosted massive sulfide deposits,” Can. Mineral. 39(6), 16171633.Google Scholar
Newnham, R. E. (1961). “A refinement of the dickite structure and some remarks on polymorphism in kaolin minerals,” Mineral. Mag. 32(252), 683704.Google Scholar
Plançon, A., Giese, R. F., Snyder, R., Drits, V. A. and Bookin, A. S. (1989). “Stacking faults in the kaolin-group minerals: defect structures of kaolinite,” Clays Clay Miner. 37(3), 203210.Google Scholar
Raudsepp, M., Pani, E. and Dipple, G. M. (1999). “Measuring mineral abundance in skarn. I. The Rietveld method using X-ray powder-diffraction data,” Can. Mineral. 37(1), 115.Google Scholar
Treacy, M. M. J., Newsam, J. M. and Deem, M. W. (1991). “A general recursion method for calculating diffracted intensities from crystals containing planar faults,” Proc. R. Soc. Lond. A 433, 499520.Google Scholar
Ufer, K., Kleeberg, R., Bergmann, J., Curtius, H. and Dohrmann, R. (2008). “Refining real structure parameters of disordered layer structures within the Rietveld method,” Z. Kristallogr. 27 (Supplement Issue), 151158.Google Scholar
Ufer, K., Kleeberg, R., Bergmann, J. and Dohrmann, R. (2012). “Rietveld refinement of disordered illite-smectite mixed-layer structures by a recursive algorithm. I: one-dimensional patterns,” Clays Clay Miner. 60(5), 507534.Google Scholar