The entire area beneath the Athabasca group is interpreted as being a continuation of the Wylie Lake complex mapped by John Godfrey in the 1980s north of Lake Athabasca. The character of the complex changes between the exposed rock north of Lake Athabasca and the core from the south of the study area. The examination of drillcores with more than one rock type present suggests the grey foliated granitoid and alkali feldspar granitoids are alkali feldspar-enriched variations of the Fishing Creek and Wylie Lake granitoids, respectively. The close relationship of the above four rock types in drill core suggests a close genetic relationship between them. The alkali feldspar-enriched varieties may result for potassium metasomatism of the Wylie Lake complex, or differentiation of the melt during ultra-metamorphism, or they may reflect a variation of mineralogy in the protolithic materials.