The Pass Lake Formation forms the lowest portion of the Sibley Group sedimentary sequence. It consists of a basal conglomerate overlain by upward thinning beds of quartz arenite which disconformably overly the Paleoproterozoic Rove Formation. This study used both SEM-EDS analyses of zircon, as well as whole rock geochemical methods in determining possible source areas for the Pass Lake Formation. The use of zircon analyses in provenance studies has been undertaken only once before by Owen (1987) in a stuffy which yielded promising results.
Zircon from the Pass Lake Formation, Redstone Point granite and two regional granite sources were analyzed for Zr, Hf, Y, Th, and U using SEM-EDS methods. Three distinctive fields were defined by the granite: Type I - Redstone Point granite field, Type II - Regional granite field, and Type III - Y, Th, U enriched field. The majority of the Redstone Point sandstone and a significant portion of the Pass Lake sandstone plot within Type I and Type II fields. Approximately 40 percent of Pass Lake sandstone zircons plot within the heavy element enriched field.
Whole rock geochemical data divide the Redstone Point, and Regional granites into three distinct fields. Pass Lake and Redstone Point sandstones plot together in a separate field which lies between the Redstone Point granite (enriched) and a Regional granite (depleted) fields. Ratio plots using Y and Zr vs Nb indicate a mixing trend in the sandstones between the Redstone Point and Regional granites.
The influence of the Redstone Point granite within the Pass Lake Formation appears to be spread throughout the sequence with a relatively constant mixing ratio between Redstone Point granitic material and other sources. Whole rock geochemical data compiled over the course of this study was compared with additional geochemical data from both published and non-published sources.