$SLIO The region surrounding Notre Dame-du-la-Salette, including the Buckingham region is a failed rift zone (aulacogen) corridor, which is a favorable environment for the presence of carbonatite. Apatite and rare earth elements (REE) are associated and often concentrated in carbonatites and associated alkaline rocks. REE are also demonstrated by the presence of the Oka pyrochlore-rich carbonatite deposit. Such concentration of Rare Earth Elements in apatite may be interpreted as an alteration of carbonatite metasomatic ore-fluids. In a study by Roeder, the total REE weight of apatite could be higher than fifteen percent(15%).(Roeder, 1987-edited)