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 heavy rare-earth elements than other Archean felsic volcanic rocks) has no plutonic equivalent in the same period. The composition of felsic volcanic rocks are being altered concurrently with shifting granitoid composition. The older GMS-like felsic volcanic rocks formed with similar age of TTG has two implications: Revealing the relationship between Archean felsic volcanic rocks and the granitoids may be difficult. It is because weathering alters the geochemical signatures of the felsic rocks above the Earth's surface. The earliest weathering record can be traced back to 3.8 Ga during Eoarchean. Potassium is enriched but sodium is depleted in these weathered felsic