Metamict fergusonite from Kolonna and Masimbula, Sri Lanka

Author(s): Annalena Erlacher, Manuela Zeug, Radek Skoda, K. A. Geeth Sameera, Lutz Nasdala
Abstract: Two radioactive mineral specimens (with compositions Th0₂ 2.9-4.6 wt% and U0₂ 5.8-7.8 wt%, respectively), collected from a placer deposit near Kolonna and a quarry near Masimbula, Sri Lank.a, were identified as metamict fergusonite. Identification was based on samples' chemical compositions and the observation that both specimens were transformed to crystalline fergusonite upon dry annealing at 550-600 °C, including the spectroscopic observation of a high-temperature α → β transition (≥750 °C) that is characteristic of this mineral. Strong negative Eu anomalies in chondrite-normalised REE patterns indicate reducing formation conditions. Both samples have experienced (perhaps even multiple) chemical alteration processes that led to the formation of decidedly
heterogeneous internal textures. Fluid-driven alteration, especially along fractures and domain boundaries, has resulted in vast chemical changes.
Organisation(s): Department of Mineralogy and Crystallography
External organisation(s): University of Vienna, University of Peradeniya, Geological Survey and Mines Bureau, Masaryk University
Journal: Journal of the Geological Society of Sri Lanka
Volume: 22-2
Pages: 1-14
No. of pages: 14
ISSN: 2719-2326
DOI: https://doi.org/10.4038/jgssl.v22i2.67
Publication date: 12-2021
Peer reviewed: Yes
Austrian Fields of Science 2012: 105116 Mineralogy, 104026 Spectroscopy
Keywords
Portal url: https://ucrisportal.univie.ac.at/en/publications/c1801236-657e-4cae-b8ce-71404b804f39

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