Abstract

Archean metasedimentary rocks in the eastern Point Lake area of the Slave Structural Province preserve a sequence of Archean structures consisting of two generations of folds (F1 and F2) with little associated penetrative cleavage and two subsequent generations of cleavage (S3 and S4) with little associated folding. Gneissic layering in the high-grade margin of the belt is composed of transposed bedding and the S3 cleavage. Folding occurred prior to the thermal peak of metamorphism, whereas the develoment of subsequent cleavages spanned the thermal peak. The regional orientation of the folds and cleavages appears to be independent of the emplacement of granitoid intrusions, although their orientation is modified adjacent to syn- to late tectonic plutons. The supracrustal belt is interpreted as being part of a pre- to early metamorphic, west-verging fold (thrust?) belt whose strain pattern has been modified by post-folding, synmetamorphic shortening, and syn- to post-tectonic plutons. This deformation sequence is similar to those described in other supracrustal belts of the Slave Province and supports the concept that the Slave Province has undergone regional, horizontally directed compression before and during intrusion of large amounts of granitoids.

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