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Lithological discrimination of altered volcanic rocks based on systematic portable X-ray fluorescence analysis of drill core at the Myra Falls VHMS deposit, Canada

Citation

McNulty, BA and Fox, N and Berry, RF and Gemmell, JB, Lithological discrimination of altered volcanic rocks based on systematic portable X-ray fluorescence analysis of drill core at the Myra Falls VHMS deposit, Canada, Journal of Geochemical Exploration, 193 pp. 1-21. ISSN 0375-6742 (2018) [Refereed Article]

Copyright Statement

2018 Elsevier B.V.

DOI: doi:10.1016/j.gexplo.2018.06.005

Abstract

Portable X-ray fluorescence (pXRF) analyzers can rapidly and inexpensively provide chemical concentrations of a range of geologically significant elements, often with instrument detection limits below 10 s of ppm. We compiled conventional XRF lithogeochemical data from Myra Falls to assess Ti/Zr discrimination criteria for volcanic-hosted massive sulfide (VHMS) host rocks at Myra Falls. Robust and discrete Ti/Zr trends for coherent volcanic rock types were identified from this dataset. To test if pXRF analysis could reproduce these trends, two experiments were designed. Single-spot pXRF analyses of pressed powdered drill core samples and three-spot pXRF analyses measured directly on the flat, cut surface of drill core samples were compared to conventional XRF results from the same sample sets. Our results indicate that both pXRF sampling methods reproduce the laboratory based XRF results for Ti and Zr, and that there is no significant improvement in accuracy or precision between drill core powders and unprepared drill core samples. We propose a calibration, estimation of total measurement uncertainty, and data reduction procedure for systematic three-spot pXRF analysis of drill core samples to improve lithological logging of altered volcanic rock types. We suggest that pXRF analysis become a routine part of lithology logging providing, for some key elements, robust and time-efficient chemical analyses with results that can be used to define important, often cryptic, lithological boundaries at Myra Falls. Portable XRF therefore has the ability to improve geological and stratigraphic interpretations, which are vital for developing mineral exploration models, for VHMS deposits and other economic mineral systems.

Item Details

Item Type:Refereed Article
Keywords:geology, pXRF, alteration
Research Division:Earth Sciences
Research Group:Geology
Research Field:Ore Deposit Petrology
Objective Division:Mineral Resources (excl. Energy Resources)
Objective Group:Mineral Exploration
Objective Field:Copper Ore Exploration
UTAS Author:McNulty, BA (Mr Brian McNulty)
UTAS Author:Fox, N (Dr Nathan Fox)
UTAS Author:Berry, RF (Associate Professor Ron Berry)
UTAS Author:Gemmell, JB (Professor Bruce Gemmell)
ID Code:129583
Year Published:2018
Web of Science® Times Cited:1
Deposited By:CODES ARC
Deposited On:2018-12-07
Last Modified:2019-03-08
Downloads:0

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