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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

Citation

Monecke, T and Kohler, S and Kleeberg, R and Herzig, PM and Gemmell, JB, 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, Canadian Mineralogist, 39 pp. 1617-1633. ISSN 0008-4476 (2001) [Refereed Article]

DOI: doi:10.2113/gscanmin.39.6.1617

Abstract

Quantitative determination of the mineralogical composition of hydrothermally altered rocks was performed by means of the Rietveld method using X-ray powder-diffraction data. Initially, experiments were carried out to minimize systematic errors arising from preferred orientation of particles as well as micro-absorption. The precision of the proposed method was tested by independent replicate sample-preparation and analyses. The closeness of the replicate phase-determinations showed that random within-laboratory errors were comparatively small. Expressed as chemical compositions, the quantitative results are in good agreement with the major oxide concentrations determined by X-ray fluorescence. The results indicate that the relative abundances of phases and refined element substitutions were accurately determined. The method developed was applied to hydrothermally altered rocks from the Waterloo volcanic-rock-hosted massive sulfide (VHMS) deposit in Queensland, Australia. Hierarchical cluster analysis led to the discrimination of several mineralogically distinct alteration-induced assemblages. These mineral assemblages are characteristic of specific zones of alteration. The strong spatial zoning with respect to the mineralized body and the distinct mineralogical assemblages of the alteration halo are interpreted to result primarily from varying degrees of hydrolytic decomposition and potassium metasomatism of the wallrocks. Based on these results, we suggest that quantitative phase-analysis by the proposed method represents a new powerful tool in studies of alteration halos.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geology
Research Field:Mineralogy and Crystallography
Objective Division:Mineral Resources (excl. Energy Resources)
Objective Group:Other Mineral Resources (excl. Energy Resources)
Objective Field:Mineral Resources (excl. Energy Resources) not elsewhere classified
Author:Gemmell, JB (Professor Bruce Gemmell)
ID Code:23251
Year Published:2001
Web of Science® Times Cited:26
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2001-08-01
Last Modified:2011-09-27
Downloads:0

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