University of Tasmania
Browse

File(s) not publicly available

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

journal contribution
posted on 2023-05-16, 13:18 authored by Monecke, T, Kohler, S, Kleeberg, R, Herzig, PM, John GemmellJohn Gemmell
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.

History

Publication title

Canadian Mineralogist

Volume

39

Pagination

1617-1633

ISSN

0008-4476

Department/School

School of Natural Sciences

Publisher

Mineralogical Association of Canada

Place of publication

Ottawa, Canada

Repository Status

  • Restricted

Socio-economic Objectives

Other mineral resources (excl. energy resources) not elsewhere classified

Usage metrics

    University Of Tasmania

    Exports

    RefWorks
    BibTeX
    Ref. manager
    Endnote
    DataCite
    NLM
    DC