Bimodal volcanism of back-arc basin formation and in the products of both continental and oceanic hotspots (e.g. Yellowstone and the Canary Islands). Bimodal volcanism is normally explained as a result of partial melting of the crust, creating granitic magmas, during the emplacement of large volumes of relatively hot basaltic magma from a mantle source. The two magma types then form separate magma chambers giving rise to periodic eruption of both types of lava. Bimodal volcanism Bimodal volcanism is the eruption of both mafic and felsic lavas from a single volcanic centre with little or no lavas of intermediate composition. This type of
Archean felsic volcanic rocks violent pyroclastic flows. Coarse breccia would be formed as a result. Submarine sediments would subsequently be deposited along the steep flank of the volcano. Submarine landslides would occur to form turbidites. Archean felsic volcanic rocks is important to deduce absolute age of the rock units in greenstone belts. Felsic eruptions are episodic so that the felsic volcanic layers are distinctive stratigraphic units. Also, felsic volcanic rocks are distributed vastly across long distances because of its extensive deposition. However, the rock sequences of greenstone belts are commonly disputed by later deformation, such as regional folding or intrusion of granitoids. By identifying