Archean felsic volcanic rocks in felsic rocks. Timing of felsic volcanism and tectonic constraints can be identified by radiometric dating and isotopic analysis. In Archean, underwater eruptions of felsic lava were common. Submarine eruption is evident by coarse volcanic breccia formed in situ, hyaloclastite or underwater pyroclastic deposits (clastic rock, composed of tephra only). Since felsic magma is viscous, volcanic eruptions that form dacite or rhyolite are explosive and violent. The Archean felsic eruption may be assigned to Vesuvius eruption type in the present day. Submarine rhyolitic flows were widespread in Archean but it is uncommon in the modern volcanic environment. Viscous felsic eruption
Lake Temagami a strong fault zone of sheared felsic to intermediate metavolcanic rocks that is approximately wide. This fault zone, known as the Northeast Arm Deformation Zone, and the associated metavolcanic rocks are associated with the Temagami Greenstone Belt, an Archean greenstone belt characterized by felsic-mafic volcanic rocks. Lake Temagami and its surrounding lakes provide endless opportunities for canoe camping. There are over 2,000 km of interconnecting canoe routes. The region contains some of the largest remaining stands of old growth red and white pine forests in Ontario. In 1834, the Hudson's Bay Company opened a fur trading post on the lake,