Apatite-iron oxide-hosted REE mineralisation at Kopslahyttan, NW Bergslagen, Sweden
2015 (English)In: Mineral Resources In A Sustainable World / [ed] A-S André-Mayer, 2015, Vol. 1-5, 781-784 p.Conference paper (Refereed)
Of the different types of REE mineralisation known from the Fennoscandian shield, the Palaeoproterozoic apatite-iron oxide ores of Kiruna type represent one resource type with significant potential. Here we describe an REE-rich apatite-magnetite mineralisation from the classic Bergslagen ore province in south central Sweden. Associated with moderately to weakly REE-enriched magnetite mineralisation of banded and vein types, the most apatite-rich occurrence at Kopslahyttan shows REE enrichment that is similar in both magnitude and pattern to other Kiruna type deposits. Yet, the present REE mineralogy is wholly dominated by monazite-(Ce), allanite-(Ce) and LREE-enriched epidote, the latter two often occurring as zoned crystals or aggregates. Minor xenotime-(Y) also occurs, and titanite locally hosts minor Y+HREE. The abundant fluorapatite is suggested to have been an additional, original host for REE, prior to fluid-mediated alteration leading to wholesale remobilisation of REE from the apatite. This remobilisation included dissolution-reprecipitation processes that lead to the nucleation of monazite in fluorapatite, but probably also further transport and precipitation as e.g. allanite/REE-epidote, through reactions with locally common silicates. In addition, we suggest that very coarse grained, variably Th-bearing monazite present in the mineralisation may have been a primary REE phase, in marked contrast to most other deposits of this type.
Place, publisher, year, edition, pages
2015. Vol. 1-5, 781-784 p.
REE; apatite-iron oxide; Kiruna type; Kopslahyttan; Bergslagen; Sweden
Research subject Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics
IdentifiersURN: urn:nbn:se:uu:diva-271009ISI: 000374801300177ISBN: 9782855550664OAI: oai:DiVA.org:uu-271009DiVA: diva2:891055
Mineral deposits in a sustainable world. 13th SGA biennial meeting 2015