GeoFile 2013-06: Determination of Major and Trace Element Concentrations in Canadian Sediment Reference Samples using Portable Energy-Dispersive X-ray Fluorescence (ED-XRF) Spectrometer and Implications for Geochemical Surveys
View GeoFile 2013-06 (PDF, 8.3 MB)
Concentrations of 24 elements (S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Rb, Sr, Zr, Mo, Sn, Cs, Ba, W, Pb, Th, U) were determined in 12 Canadian sediment reference samples using a portable energy-dispersive X-ray fluorescence (ED-XRF) spectrometer and Compton scatter radiation for matrix correction. The reference samples represent till, stream sediments, and lake sediments that have been widely used as quality-control standards in geochemical surveys. A total of 11 international certified reference materials were analyzed to calibrate the ED-XRF spectrometer using error-weighted least-squares regression of the measured and the recommended data. The ED-XRF results are consistent with the published data within the uncertainties for V, Cr, Ni, Cu, Zn, As, Rb, Sr, Zr, Mo, W, and Pb in the reference sediment samples. Magnitude of bias for S, Ca, K and Ba concentrations appears to correlate with high loss-on-ignition (mainly H2O) contents (up to 44 wt. %) in these samples. Concentrations of Ti, Mn and Fe in all samples show small but significant systematic error, whereas Cs, Ba, Th and U concentrations may reflect spectral interferences in some samples. Concentrations of Co, Ag, Cd, Sb, Au, and Hg in the analyzed reference samples are all below the detection levels of the portable ED-XRF. Precision of the ED-XRF analyses is better than 6% (average 1.6%) at the 2σ level for most of the trace elements, except Cs. The portable ED-XRF spectrometer, with Compton scatter normalization for matrix correction, can be used for precise and accurate analysis of till, stream- or lake-sediment samples in mineral exploration, geochemical mapping and environmental monitoring. Compared to other analytical methods, the technique is fast, non-destructive, and requires less sample preparation.
Poster presented at the annual Mineral Exploration Roundup Conference, sponsored by the Association for Mineral Exploration British Columbia (AMEBC) in January, 2013.
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