REY plus ACT redistribution in polymineral aggregates: a case study on monazite decomposition in pegmatite
Authors | |
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Year of publication | 2024 |
Type | Article in Periodical |
Magazine / Source | Review of the Bulgarian Geological Society |
MU Faculty or unit | |
Citation | |
web | https://bgd.bg/REVIEW_BGS/REVIEW_BGD_2024_2/PDF/16_Vassileva-1_REV-BGS_2024-2.pdf |
Doi | http://dx.doi.org/10.52215/rev.bgs.2024.85.2.124 |
Keywords | pegmatite; monazite-(Ce); allanite-(Ce); complex multimineral aggregates |
Description | Selected pegmatite dyke intruded within the gneiss-marble-amphibolite sequence of the Rhodope Metamorphic Complex was studied for its REY+ACT mineralization in attempt to assess the potential of these pegmatites for critical and strategic raw materials. Mineral composition of K-feldspar and albite is complemented by abundant common accessories of zircon, apatite, monazite, allanite, and titanite. The REY+ACT mineralization is presented as single euhedral crystals (zircon, thorianite, Y-Nb oxide, titanite and fluorapatite) or as complex multimineral nodule-like aggregates. The nodule core typically consists of decomposed Th-bearing monazite-(Ce) altered to different degree by intergrown Th-bearing apatite/thorite assemblage. Fluid-involved reactions led to mineral transformations and redistribution of the elements like LREE, Y, Th, U, and formation of the inhomogeneous allanite-(Ce)/REE-epidote rims enveloping the aggregated earlier phases. |