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Minerals of base metals
Published in Francis P. Gudyanga, Minerals in Africa, 2020
Monazite is a phosphate mineral that contains rare earth metals in four different groups determined by the composition of the REMs present: Monazite-(Ce), (Ce, La, Nd, Th)PO4Monazite-(La), (La, Ce, Nd)PO4Monazite-(Nd), (Nd, La, Ce)PO4Monazite-(Sm), (Sm, Gd, Ce, Th)PO4 Monazite which may contain some silica is an important source of thorium [585], lanthanum and cerium [586]. Monazite, often found in placer deposits, is radioactive due to the presence of thorium and uranium.
Unusual REE fractionation and occurrence of monazite-(La,Ce) in single monazite grains from a “Central” gold-quartz vein at Muruntau (Uzbekistan)
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
U. Kempe, T. Graupner, D. Wolf, A.A. Kremenetsky
The most common monazite type is monazite-(Ce) containing 4-12 wt % Th and low U contents (Förster 1998). Such monazite was usually found in granites as well as in most metamorphic rocks and placers. Samples with low Th contents seem to be typical of monazite of non-magmatic origin indicating involvement of fluids in monazite formation, e.g. in greisenized granites (cf. Semenov 1963). Reports of monazite from hydrothermal veins are scarce (Semenov 1963, Mariano 1989). Th, U, Y, Nd and heavy REE are enriched in monazite from granites and pegmatites with associated rare metal mineralization (W, Sn, Nb, Ta, Be). The enrichment of the heavy REE is a typical feature of such ore systems. Accordingly, monazite-(Nd) was described from several related localities (e.g. Semenov 1963, Förster 1998). Another important variety of monazite represents the so-called “dark” monazite enriched in Eu (Mariano 1989, Kremenetsky 1993).
Occurrence, geochemistry and provenance of REE-bearing minerals in marine placers on the West Coast of the South Island, New Zealand
Published in New Zealand Journal of Geology and Geophysics, 2021
Stephanie L. Tay, James M. Scott, Marshall C. Palmer, Malcolm R. Reid, Claudine H. Stirling
A suite consisting of mostly lamprophyres with minor ultramafic lamprophyre, camptonite, sodalite tinguaite, trachyte and carbonatite form the Alpine Dike Swarm in the Alpine Schist in northwest Otago and south Westland (Cooper et al. 2016). The Alpine Dike Swarm formed during transtensinal development of the Alpine Fault duing the late Oligocene–early Miocene (Cooper et al. 1987, 2016). The carbonatites are depleted in light REE (LREE) and heavy REE (HREE) but are relatively enriched in middle REE. REE-bearing minerals found associated with the carbonatites include apatite, aeschynite, ancylite-(Ce), daqingshanite-(Ce), fergusonite, monazite-(Ce), monazite-(Nd) and three unidentified Ca–Ba–Sr REE minerals (Cooper and Paterson 2008; Cooper et al. 2015).