Rare earth elements in carbonatite and cogenetic alkaline rocks: Examples from Seabrook Lake and Callander Bay,Ontario

Associated rocks from the Seabrook Lake, carbonatite complex in Ontario show an increase in total REE (rare earth element) content and in light REE enrichment in the following order: fenite quartz monzohite 1% garnet, to produce residual melts with the REE contents of the ijolite. (3) The carbonatite may represent an immiscible carbonate-rich liquid which separated from the parent ijolite liquid, as suggested by REE distribution coefficients between carbonatite and ijolite at Seabrook Lake similar to those obtained for carbonate-rich ocelli and associated lamprophyre at Callander Bay.The similar REE contents of the fenites and country rock, and the much lower REE contents of the fenites than the associated ijolite, mafic breccia, and carbonatite, suggest that the fenites may be country rock altered by CO₂ and H₂O-rich fluids.