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

• Published in: Canadian Journal of Earth Sciences
• Main Authors: Mumford, T.R. (Thomas R.), Cousens, B. (Brian)
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2014
• Subjects: Blatchford Lake; Canada; East Arm; Great Slave Lake
• Online Access: https://ir.library.carleton.ca/pub/7711; https://doi.org/10.1139/cjes-2013-0124

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 Blatchford Lake intrusive suite support a petrogenetic association, but suggest that parts of the Compton intrusive suite are older than 1865 Ma. Relations between local northwest-trending diabase dykes and the intrusive stocks suggest that the dykes include two sets, one of which is coeval with the intrusion of the stocks. Results from this study indicate that locally a more protracted and complex magmatic history exists than previously considered, a feature that may be reflected in the regional geology.