Characterisation of phosphate mineralogy in Montebras-en-Soumans Pegmatite, Massif Central, France

Montebras-en-Soumans pegmatitic cupola hosts large pods of phosphate composed of primary amblygonite-montebrasite. These aluminium phosphate masses are considerably altered by post-magmatic processes producing a number of secondary metasomatic hydrothermal phosphates (lacroixite, wardite, morinite, viitaniemiite, apatite, triplite, eosphorite) and low-temperature phosphates (apatite, crandallite, goyazite, gorceixite, variscite, turquoise, wavellite). Also found in this study are a Mn-rich viitaniemiite-like phase and an unknown Na-Al-P fluoride. A number of techniques are used to characterise these mineral phases including optical studies, cathodoluminescence (cold & hot), electron-probe micro-analysis (wavelength & energy dispersive spectra), X-ray diffraction, laser ablation inductively coupled plasma mass spectroscopy and infrared spectroscopy.