| Summary: | Reconnaissance geological mapping has been carried out on 8500 sq km centered on the northern part of Reindeer Lake in northern Saskatchewan. Parts of four major litho-structural domains occur in the area: from northwest to southeast they are the Whiskey Jack Domain, the Rottenstone Domain, the La Ronge Domain, and the Kisseynew Domain. This map area lies primarily in the Rottenstone Domain. The Whiskey Jack Domain (a new name proposed here) includes an Archaean granite basement overlain by the Aphebian Wollaston metasedimentary gneisses, both of which have been partially remobilized during the Hudsonian Orogeny. In the northwest, the Rottenstone Domain contains granitoid and younger gabbroic rocks, both of possible Archaean age. Large areas in the central portion of the domain are underlain by rocks of the Hudsonian Wathaman Batholith. In the southeastern part of the domain, Aphebian migmatitic and metasedimentary gneisses are intercalated with granitic rocks. The La Ronge Domain consists principally of granodioritic bodies, forming part of the South Reindeer Batholith (a term proposed in this study). It also contains the La Ronge metasedimentarymetavolcanic gneisses. Both granites and gneisses were folded during the Hudsonian Orogeny. The Kisseynew Domain is restricted to a small area. It contains both the La Ronge and Burntwood River gneisses, which are intercalated with deformed granitic bodies. Twenty five major rock units were mapped, these include metasedimentary and metavolcanic rocks, mylonites, basic and granitic rocks. Major element chemistry indicates that some of the granitic rocks have been magmatically fractionated. Field evidence indicates that other granitic bodies possibly have been formed by metasomatism and anatexis especially near the southern contact of the Wathaman Batholith, a conclusion not completely supported by the major element chemistry. The present study establishes that the Needle Falls Shear Zone and the Wathaman Batholith together are related to a major crustal discontinuity. ...
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