title: (234)U/(238)U signatures associated with uranium ore bodies: part 2 Manyingee.
abstract: The Manyingee ore body is a roll-front U ore body located at depth in the Cretaceous sandstone sediments of a Proterozoic palaeo valley. It is located in a confined aquifer. The aquifer is recharged 4 km upstream by the Ashburton River. Groundwater samples were collected at and up to 4.7 km downstream of the ore body. The ground water (234)U/(238)U activity ratios (AR) were elevated to 1.86 in the vicinity of the ore body and then declined to 1.06 over the 4.7 km transect. The elevated (234)U/(238)U ARs are attributed to selective leaching of (234)U sites by oxidising waters, with α recoil as a necessary precursor to produce activated (234)U sites. Direct ejection into another phase following α recoil is considered to be a minor contributor to (234)U -(238)U disequilibrium in this environment. The profile is considered to be typical of the (234)U/(238)U AR profile at and down gradient of the redox front of a U ore body.
authors.affiliation: Institute for Environmental Research, Australian Nuclear Science and Technology Organisation, Lucas Heights Research Laboratories, Private Mail Bag 1, Menai, NSW 2234, Australia. richardlowson@yahoo.com.au
authors.forename: Richard T
authors.initials: RT
authors.lastname: Lowson
authors.forename: Mark G
authors.initials: MG
authors.lastname: McIntyre
mesh_terms: D004784:Environmental Monitoring; D060587:Groundwater / Q000032:analysis; D014501:Uranium / Q000032:analysis*; D014872:Water Movements; D014875:Water Pollutants, Radioactive / Q000032:analysis*
chemical_list: D014875:Water Pollutants, Radioactive; D014501:Uranium