Supergene Uranyl Mineralization of the Rabejac Deposit, Lodève, France

The Rabejac uranium deposit that is located in the Lodève region, France, is the type locality for three uranyl minerals species (fontanite, seelite, and rabejacite). In addition, this deposit shows an extraordinary supergene uranyl mineralization characterized by the presence of many rare secondary uranyl species. In the present study, a mineralogical description as well as new chemical and crystallographic data are reported on (meta)zeunerite, (meta)nováčekite, (meta)uranospinite, heinrichite, nováčekite-I, arsenuranospathite, umohoite, calcurmolite, becquerelite, billietite, and liebigite. The chemical data indicate that the arsenate members of the autunite/meta-autunite group incorporate a significant amount of phosphorus. Moreover, the uranospinite samples usually exhibit high Mg content, thus moving toward the nováčekite end-member composition. The refined unit-cell parameters for all of the investigated mineral species are in agreement with the previous data reported in the literature. Finally, a model describing the alteration of the primary uraninite and the formation of secondary uranyl minerals is proposed in agreement with the observed mineral assemblages.