Publication details
Rare-earth element mineralization in altered pegmatites from the Djurkovo Pb-Zn deposit, Central Rhodopes
| Authors | |
|---|---|
| Year of publication | 2023 |
| Type | Article in Proceedings |
| Conference | 17th Biennial SGA Meeting - Proceedings Volume 1 |
| MU Faculty or unit | |
| Citation | |
| web | https://www.e-sga.org/fileadmin/PDF/Conference_proceedings/Zuerich/SGA_2023_Zurich_Volume_1.pdf |
| Keywords | Djurkovo deposit; polymetallic vein; pegmatite dykes; high-grade metamorphic complex; Central Rhodopes; gneisses |
| Description | The Djurkovo polymetallic vein deposit is formed by veins filling open space in various gneisses that compose the high-grade metamorphic complex in the Central Rhodopes. Abundant deformed concordant or crosscutting pegmatites of varying thickness are common in the metamorphic sequence. The studied pegmatite dykes consist mainly of plagioclase, K-feldspar, quartz, and minor micas. The main accessory minerals are allanite- (Ce), titanite, apatite and zircon. Late hydrothermal overprint and alteration of pegmatites led to formation of epidote-group minerals, adularia, albite, sericite, chlorite, carbonate, quartz and leucoxene. The secondary minerals also include rare earth element (REE+Y) and Th, U fluorcarbonate - phosphate - oxide assemblages. This mineral association typically occurs as very fine-grained (. 20 mu m) anhedral disseminations, observed along fractures and dissolved zones in allanite and titanite that evidently are the main source for the REEs. This indicates remobilization of REEs followed by formation of new phases during the late-stage hydrothermal activity. Limited mobility of REEs is illustrated by precipitation of the newly-formed minerals within the grains of the altered accessory minerals. The studied pegmatites retain a significant amount of accessory minerals rich in incompatible elements and despite being hydrothermally altered they could be considered as their potential source. |