Felsic and mafic magma commingling accompanied by Ca-metasomatism of xenocrysts, followed by K-metasomatism of solidified felsic tonalite to form quartz monzonite and granite in the Chief Lake granitic complex south of Sudbury, Ontario, Canada

South of Little Raft Lake in the Chief Lake granitic complex, south of Sudbury, Canada, Na-rich, felsic magma locally commingled with a Na-rich mafic magma. In addition, subhedral quartz and large sodic plagioclase phenocrysts floated-off from the felsic magma to become isolated xenocrysts in the mafic magma. Reactions of the quartz xenocrysts with the relatively more-calcic mafic magma produced rims of tiny amphibole crystals. Ca-metasomatism of borders of the sodic plagioclase xenocrysts by mafic magma locally resulted in aggregate myrmekite rims with tiny quartz vermicules, intermeshed with tiny amphibole crystals. The mafic magma crystallized as a fine-grained mafic tonalite containing more than 30 volume percent biotite, and locally, the felsic magma crystallized as coarse-grained felsic tonalite in small, agmatitic patches and veins in the mafic tonalite. Following this crystallization, portions of the mafic tonalite and agmatite were enclosed as large enclaves in a much larger mass of felsic tonalite magma. After all magmatic rocks were solidified, cataclasis allowed fluids to move through microfractures and release K from the abundant biotite. This K was then precipitated as K-feldspar (microcline) that replaced deformed plagioclase crystals, (a) in xenocrysts in the mafic tonalite, (b) in patches of coarse-grained felsic tonalite in agmatite, and (c) in the larger mass of coarse-grained felsic tonalite that enclosed the large enclaves. In this way, the compositions of the felsic agmatite patches and the larger felsic tonalite masses were locally changed into quartz monzonite and granite, depending upon the degree of K-metasomatism. Similar metasomatic modifications of magmatic quartz diorite and quartz monzonite also occur in the Chief Lake granitic complex north and northeast of Wavy Lake, but the felsic tonalite here in agmatite lacks any signs of K-metasomatism. The\ud metasomatically modified granitic rocks in the Little Raft Lake and Wavy Lake\ud areas become models for creation of all the various granitic facies of the Chief\ud Lake complex in which cataclastically deformed portions of primary quartz diorite\ud masses of magmatic origin were converted to quartz monzonite and granite. In\ud each of these places, myrmekite with tiny quartz vermicules provides additional\ud evidence for K-metasomatism