GeoFile 2011-5: Biogeochemical Exploration Vectors in Search of Carbonatite, Blue River, British Columbia
View GeoFile 2011-5 (PDF, 32.4 MB)
Coniferous trees represent suitable sampling media in the exploration for carbonatites and related rare earth elements (REE), Ta, Nb, phosphate and fluorspar mineralization referred to in the British Columbia “Carbonatite Deposit profile N01” (Birkett and Simandl, 1999).
Twenty four samples of twigs with needles from coniferous trees (Subalpine Fir and White Spruce) were collected over the Upper Fir Ta, Nb and apatite-bearing carbonatite. The results indicate that carbonatite is detectable by biogeochemical methods. Light rare earth elements (LREE), Y, Zr and P are good exploration vectors for REE and apatite mineralization; whereas Ta and Nb are direct indicators for their own ores. Ta is found in detectable concentrations only in White Spruce twigs (41% of samples), and mainly those directly overlying mineralization, concentrations range from 0.001 to 0.003 ppm Ta. Nb concentrations are higher than those of Ta; concentrations range from 0.02 to 0.24 ppm Nb in White Spruce twigs, 0.00496 to 0.070814 ppm Nb in White Spruce needles (ash values normalized to dry weights), and 0.012011 ppm to 0.030214 ppm in Subalpine Fir needles (ash values normalized to dry weights).
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