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Abstract:

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.