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TitleApplication of portable XRF to the direct analysis of till samples from various deposit types in Canada
AuthorHall, G E M; McClenaghan, M B; Pagé, L
SourceTribute to Eion M. Cameron; Geochemistry: Exploration, Environment, Analysis 16, 1, 2016 p. 62-84,
LinksDatasets - Ensemble de données
Alt SeriesEarth Sciences Sector, Contribution Series 20150366
PublisherGeological Society of London
Mediapaper; on-line; digital
RelatedThis publication is related to the following publications
File formatpdf
ProvinceNorthwest Territories; Ontario; New Brunswick
NTS21J/02; 21J/03; 21J/06; 21J/07; 21O/08; 31M/05; 85B/09; 85B/10; 85B/15; 85B/16
AreaPine Point Mining District; Halfmile Lake; Nashwaak River; Great Slave Lake; Lake Timiskaming
Lat/Long WENS -66.3336 -66.2917 47.3167 47.2833
Lat/Long WENS -67.1000 -66.9167 46.4167 46.2167
Lat/Long WENS-114.9167 -114.0000 61.0000 60.6667
Lat/Long WENS -79.7611 -79.7611 47.4533 47.4514
Subjectssurficial geology/geomorphology; economic geology; geochemistry; mineral exploration; drift prospecting; glacial deposits; tills; till analyses; till geochemistry; field methods; mineral deposits; copper; lead; zinc; tungsten; molybdenum; kimberlites; indicator elements; sample storage; bedrock geology; spectroscopic analyses; ice transport directions; Bathurst Mining Camp; Sisson deposit; Lake Timiskaming kimberlite field; Triple B kimberlite; volcanic-hosted massive sulphide deposits; Mississippi Valley type deposits; sample bags; Phanerozoic; Cenozoic; Quaternary
Illustrationsgeological sketch maps; location maps; cross-sections; plots; spectra; bar graphs
ProgramTargeted Geoscience Initiative (TGI-4), Intrusion/Porphyry Ore Systems
ProgramGEM: Geo-mapping for Energy and Minerals
ProgramTargeted Geoscience Initiative (TGI-1), 2000-2003
ProgramTargeted Geoscience Initiative (TGI-3), 2005-2010
Released2015 12 17
AbstractIn this study, results by direct portable XRF ('pXRF') on unsieved till samples were compared with those by established laboratory methods (aqua regia or fusion ICP-MS and ICP-ES) on the <0.063-mm fraction to determine if the application of direct pXRF in the field would serve as an acceptable guide for immediate follow-up work. Four test sites in Canada were chosen: the Halfmile Lake Cu-Pb-Zn VMS deposit; the intrusion-hosted W-Mo Sisson deposit; a Pb-Zn Mississippi Valley-type (MVT) deposit in the Pine Point district; and the Triple B kimberlite. Unsieved till samples from the GSC archive collection were used for this study and included samples from background areas, immediately overlying, and at various distances down-ice of each deposit. Ziploc® and Whirl-Pak® bags that were used to contain the samples in the field were tested for their properties of X-ray attenuation and contamination. In general, the performance of pXRF in the four test areas was very good where concentrations of elements of interest (indicator or pathfinder elements) were substantially above detection limits by this technique (in the low ppm range for many elements). The following elements, shown to be useful indicator elements (important constituents of the ore/commodity) or pathfinder elements (those associated with the commodity elements) by the established methodology, showed similar patterns by pXRF on the unsieved material: Zn, Cu, Pb, and As at Halfmile Lake; W, Mo, Cu, Zn, Pb, and As at the Sisson deposit; Zn, Pb, and Fe at Pine Point; and Ca, Sr, Cr, and Ni at Triple B. Pathfinder elements whose concentrations were too low for determination by pXRF include: Ag and Sb at Halfmile Lake; Ag and Cd at Sisson; Cd, S, and Se at Pine Point; and Co, Mg, P, U, and Th at Triple B. The high background for Bi by pXRF, equivalent to c. 50 ppm, and its noisy signal precluded its use at Halfmile Lake and Sisson. Elements which tended to show poor precision (three analyses each sample) by pXRF in some samples due to sample heterogeneity include Sn, V, and W. Mercury was erroneously reported for the majority of samples in the low ppm range by pXRF whereas its concentration in fact was in the low ppb range. Several Pb-, Zn- (c. 1% Pb, Zn) and Fe-rich (up to 16% Fe) samples demonstrated spectral interferences by: Pb on As, Th and Se; Zn on Cu; and Fe on Co. Results for six till samples analysed in Ziploc® and Whirl-Pak® bags showed that Ziploc® absorbs fewer low-energy photons and hence is preferable for determining light elements such as Si, K and Ca.
Summary(Plain Language Summary, not published)
This journal paper describes how to apply portable xrf methods to till samples collected in the field and provides an evaluation of the major and trace elements that will be useful around four mineral deposit types: volcanogenic massive sulphide, Mississippi Valley Type lead-zinc, intrusion-hosted tungsten-molybdenum, and kimberlite.