GEOLOGY

Detailed explanation-1: -generation. Granitic, or rhyolitic, magmas and andesitic magmas are generated at convergent plate boundaries where the oceanic lithosphere (the outer layer of Earth composed of the crust and upper mantle) is subducted so that its edge is positioned below the edge of the continental plate or…

Detailed explanation-2: -Occurrence. Rhyolite is common along convergent plate boundaries, where a slab of oceanic lithosphere is being subducted into the Earth’s mantle beneath overriding oceanic or continental lithosphere. It can sometimes be the predominant igneous rock type in these settings.

Detailed explanation-3: -Shield volcanoes are formed by basaltic magma, typically above a mantle plume, whereas the stratovolcanoes (sometimes referred to as composite volcanoes) are formed by andesitic/rhyolitic magma.

Detailed explanation-4: -Where hotspots occur in continental regions, basaltic magma rises through the continental crust, which melts to form rhyolites. These rhyolites can form violent eruptions.

Detailed explanation-5: -Rhyolitic magma can also be produced by changing the chemical composition of basaltic magma as discussed later. Transfer of heat by this mechanism may be responsible for generating some magmas in continental rift valleys, hot spots, and subduction related environments.