The geochemistry of loveringite, a uranium-rare-earth-bearing accessory phase from the Jimberlana Intrusion of Western Australia

Abstract

SummaryThe distribution and geochemistry of loveringite, an accessory Ti, Fe±Cr oxide containing U and rare-earth elements (Ln) from the Jimberlana Intrusion, have been studied. Loveringite is most abundant in bronzite cumulates; it is found in trace amounts in early plagioclase-augite-hypersthene cumulates, but is not found in the olivine cumulates or in the late-stage differentiates. Loveringites from the bronzite cumulates have a high Cr content compared with those from the plagioclase-augite-hypersthene cumulates, suggesting that the mineral is stabilized by the presence of Cr in the intercumulus liquid. The Ln pattern shows a strong depletion trend from La to Eu, a sharp reversal between Eu and Tb and a second depletion pattern from Tb to Lu. This pattern suggests that the Ln are substituting into two sites, one much larger than the other.