Napoleon Bay

Napoleon Bay, Baffin Island, Canada hosts a series of NW-SE to W-E trending, ~2 m thick lamproite dykes. These structures are known as the Baffin Dykes, and intrude biotite gneiss, mafic gneiss, and anorthosite likely belonging to the metaplutonics of the Paleoproterozoic Torngat orogeny. The lamproites are melanocratic and porphyritic with common phenocrysts of phlogopite, leucite, and sanidine, with rarer forsterite and pyroxene. Except for chilled margins, leucite is commonly replaced by pseudoleucite formed of kalsilite and sanidine. Amphiboles are richterite-arfvedsonite, and pyroxenes exist as both major diopside and minor aegirine-augite and aegirine. Notable accessories include lorenzite, possible barytolamprophyllite, batisite. Detailed petrology and mineral chemical analysis can be found in Hogarth (1997).