Constraints on the relationships between Paleoproterozoic intrusions and dyke swarms, East Arm of Great Slave Lake, N.W.T., Canada

Abstract

Paleoproterozoic magmatism in the southern Slave region records the tectonic breakup of Scalvia and the formation of Nuna/Columbia. Constraints on Paleoproterozoic intrusions, therefore, have a direct influence on tectonic reconstructions of this period. This study focuses on select Paleoproterozoic intrusions in the southern Slave Craton proximal to and intruding the 2.17 Ga Blatchford Lake intrusive suite, particularly local diabase dyke swarms and two poorly documented plutonic stocks hosted within the Blatchford Lake intrusive suite. The geochemistry and geochronology of these two 1892 ± 4 Ma monzonite–diorite stocks suggest that they likely represent the only northwestern extension of the Compton intrusive suite into the Slave Craton. Detailed mapping of these stocks identified cross-cutting diabase dykes and spectacular rhythmically layered gabbroic rafts. The geochemical similarities between the Compton intrusive suite sills located in the East Arm and the two intrusive stocks hosted in the Blatchf...