Graphic-textured inclusions in apatite: Evidence for pegmatitic growth in a REE-enriched carbonatitic system
Publication Type:
Journal ArticleSource:
GeologyGeology, Volume 43, Number 6, p.547-550 (2015)ISBN:
1943-2682<br/>0091-7613Abstract:
Graphic texture, most common in felsic pegmatites, is documented here in an unusual setting, within apatite of the Hoidas Lake light rare earth element (LREE) deposit, an inferred distal pegmatitic-hydrothermal counterpart of a carbonatite in northern Saskatchewan, Canada. The graphic texture is displayed by vermicular and cuneiform LREE-rich inclusions which define primary growth zones in apatite. Integrated electron microprobe analysis and scanning electron microscope–energy dispersive X-ray spectroscopy imaging document the unusual and heterogeneous compositions of the inclusions, which vary between Ce2O3 + SiO2 (+ ThO2)–dominant and La2O3 + Nd2O3 (+ F)–dominant end members. Here we discuss the formation of these graphic-textured inclusions in the context of models suggested for the formation of graphic quartz–K-feldspar intergrowths in granitic pegmatites, based on the similarity of these features.