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TitreAn assessment of the precision and accuracy of a portable XRF analyzer compared to, fusion ICP-emission spectrometry, and Aqua Regia ICP-mass spectrometry
AuteurKnight, R D; Garrett, R G; Russell, H A J
SourceAssociation géologique du Canada-Association minéralogique du Canada, Réunion annuelle, Programme et résumés vol. 34, 2011 p. 110
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20100433
ÉditeurAssociation géologique du Canada
Réunion2011 GAC-MAC-SEG-SGA Joint Annual Meeting; Ottawa; CA; mai 25-27, 2011
Documentpublication en série
Mediapapier; en ligne; numérique
Sujetsfluorescence aux rayons x; analyses de fluorescence; méthodes de prospection; analyses par diffraction des rayons x; diffraction des rayons x; trous de mine; analyses spectrométriques; géochimie
ProgrammeDiamands, GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Portable X-ray fluorescence (XRF) analyses provide an efficient, cost-effective, and non-destructive method to measure variations
in elemental concentrations in sediment samples. For fine-grained materials analytical wet geochemistry, X-ray diffraction (XRD)
analyses, and petrographic and microbeam analyses are commonly used to determine elemental abundances and related mineralogy.
These methods can be time consuming and expensive especially when a large number of analyses are required. Portable XRF
analyses are an increasingly common method used to determine high-resolution elemental abundances at a fraction of the cost and
time of wet chemistry.This study assesses the validity of using a NITON XL3t GOLDD hand-held XRF analyzer in Soil Mode to define the
chemostratigraphy of a 90 metre borehole through late Pleistocene Champlain Sea sediments near Ottawa, Ontario. Samples analyzed
using the portable XRF unit are compared with results obtained by ICP-emission spectrometry following a Lithium metaborate/tetraborate fusion and by an ICP-mass spectrometry following an aqua-regia digestion. Seventeen elements (K, Ca, Mn, Fe, As, Rb, Sr, Ba, Ni, Cu, Zn, Cr, Ti, V, Sc, S, and Zr) were in sufficient quantities to be detected by the XRF analyser. Quadruplicate analyses for each sample were compared using the R statistical computing and graphics software package. For all detected elements excluding Mo, Ni and S the probability that the differences between the results are due to instrument variability is close to zero therefore the difference between samples at different stratigraphic depths reflects a real change in elemental abundance. For Mo, Ni, and S many of the analyses are near or below the detection limit. Although the values detected by all three methods often varied, the trends of either increasing or decreasing elemental abundances between each method is remarkably similar. This study demonstrates that portable XRF tools, particularly
the NITON XL3t can be used with confidence in chemostratigraphic analyses of fine grained sediment with a Canadian Shield
provenance. Comparison of results with a dataset analyzed by conventional means indicates that some differences occur between
absolute values between the two methods. This difference however is relatively minor, and for the most part is no greater analytical
variability observed between many methods. Data resulting from this method has applications in prescreening samples for further often destructive analyses, identification of parent source rocks, changes in depositional conditions, and augments classical core logging techniques including, micro palaeontology, downhole geophysics and wet geochemistry.