Recent mapping in the ‘Windy McKinley’ terrane of Stevenson Ridge area of western Yukon defined two subdivisions of the terrane, an imbricated ophiolite and a succession of predominantly fine-grained, variably carbonaceous and calcareous clastic rocks extensively intruded by Middle Triassic gabbro. Further work in 2007 has revealed a third subdivision of felsic metavolcanic and carbonaceous clastic rocks, also spatially associated with voluminous gabbro. The two subdivisions of the terrane containing gabbro are reminiscent of the two subdivisions of the Delta district of Alaska, and gabbroic rocks from the two areas are coeval and geochemically similar. If the Stevenson Ridge successions correlate with those of the Alaska Range, the mineral potential of the Stevenson Ridge area would be appropriately increased.
