Temagami Greenstone Belt phases of volcanic activity. These two sequences, known as the Older and Younger volcanic complexes, consist of volcanic rocks ranging in composition from felsic to mafic. The Older Volcanic Complex is composed mainly of felsic lava flows and pyroclastic deposits with smaller amounts of mafic volcanic rocks. It underlies a large portion of northwestern Strathy Township and is penetrated by mafic intrusions, although the Kanichee Intrusion consists of peridotite and pyroxenite, which are ultramafic rocks. Just to the southeast, the Younger Volcanic Complex consists mainly of mafic volcanic rocks that form four geologic formations. The Arsenic Lake Formation is composed
Archean felsic volcanic rocks (b) melting of felsic materials (e.g. TTG and/or sediments) formed younger potassium-rich GMS (see Table 3). They imply gradual chemical changes of the in the magma and the Earth's crust. Records of Archean felsic volcanic rocks shows a peculiar trend. The eruption of felsic volcanic rocks and plutonic activities in Archean are largely synchronised as show in overlapping zircon ages. On contrary, the chemical compositions of some felsic volcanic rocks are similar to that of GMS but they are much older than GMS. For example, a GMS-like rhyolite unit in the Abitibi Greenstone Belt (abnormally more enriched in potassium and