LA-ICP-MS Mapping of Barren Sandstone from the Proterozoic Athabasca Basin (Canada)—Footprint of U- and REE-Rich Basinal Fluids

The Proterozoic Athabasca Basin hosts a large number of high-grade, large-tonnage unconformity-related uranium (U) deposits, many which are also enriched in rare earth elements (REE). basin contains hydrothermal REE mineralization unassociated with U. Previous studies postulated that U and were derived from either the or basement; however, exact source metals remains ambiguous. This study provides evidence U- REE-rich fluids throughout through laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) mapping barren sandstone distal to mineralized areas. results indicate elevated concentrations mainly occur matrix; there strong positive correlations between REE, Th, P Sr, moderate Zr, Ba, Fe, Al, K Ca, but few spots highest unrelated these elements. Quantitative evaluation element correlations, together scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) analysis, suggests most hosted aluminum phosphate sulfate (APS) minerals rather than apatite monazite. As APS diagenetic-hydrothermal origin, testify presence within Basin. Th/U ratio (~10) pattern (strong heavy (HREE) depletion) consistent model amounts (especially HREE) leached contributed near unconformity sedimentary rocks underlying basement rocks. demonstrates LA-ICP-MS can be effectively used evaluate microscale distribution their mobility address related problems.