Rainy Ridge

Rainy Ridge of southwestern Alberta, Canada hosts a 5-7 m thick analcime phonolite sill, emplaced within the Gateway Formation of the Proterozoic Purcell Supergroup. It appears pale graygrey and massive, with phenocrysts of sanidine, aegirine-augite, melanite garnet, analcime, hastingsite, titanite, and apatite forming ~12% of the rock. The gGroundmass consists of sanidine microlites, analcime, aegirine-augite, hastingsite, and hydrogarnet. In weathered sections, analcime pseudomorphs of sodalite and muscovite are present. This sill is thought to be linkedmay be genetically to the Crowsnest Volcanics 20 km to the north. Mineral chemical and whole rock data can be found in Goble et al., (1993).