Publication Summary
Issue ID: P2014-01-12
Title: Portable x-ray fluorescence to optimize stream sediment chemistry and indicator mineral surveys, case 2: Carbonatite-hosted REE deposits, Wicheeda Lake, British Columbia, Canada
Author(s): Mackay, D.A.R., Simandl, G.J.
Series Name: Paper
Publication Year: 2014
Larger Work Citation: in Geological Fieldwork 2013, B.C. Ministry of Energy and Mines, Paper 2014-01
NTS Map Sheet(s): 093J/09
Place Keyword(s): British Columbia, central
Lat/Long (NSWE): 54.56, 54.49, -122.12, -122.03
Theme Keyword(s): indicator minerals, pathfinder elements, rare earth elements, specialty metals, portable x-ray fluorescence
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Abstract:
The Wicheeda carbonatite-hosted deposit is one of the most promising rare earth element (REE) prospects within the British Columbia alkaline province. Portable x-ray fluorescence (pXRF) allows for determination of several pathfinder elements (Nb, Ta, REEs, Th, Ba, and Sr) in stream sediment samples collected downstream of this deposit. These samples are expected to contain indicator minerals derived from the main carbonatite complex such as monazite, REE-bearing carbonates and fluorocarbonates, pyrochlore, columbite-(Fe), barite-celestine, apatite, and others. Study of these samples indicates that the + 250 µm, + 125 µm, and + 63 µm size fractions contain high concentrations of Nb, La, Ce, and Th relative to other size fractions. The + 125 µm fraction was chosen for systematic chemical analyses and pathfinder element studies. Although there is no noticeable decreasing trend in pathfinder elements with increasing distance downstream, there is co-variation of Nb, Ta, La, Ce, Pr, Nd, Y, and Th. This reflects the presence of multiple mineral phases including pyrochlore, monazite-(Ce), REE-fluorocarbonates, and REE-carbonates. Mineralogical studies using optical microscopy, scanning electron microscopy (SEM), electron microprobe (EMP), and Quantitative Evaluation of Materials by Scanning electron microscopy (QEMSCAN) are required to identify and quantify minerals and their distributions downstream of the deposit.