Stratovolcano Stratovolcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava, tephra, pumice and ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and hardens before spreading far due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma. Extensive
Huangling Complex Craton during subduction beneath the North China Craton. As the oceanic Yangtze Craton subducted under the continental North China Craton, magmatic activities result in the formation of hydrated mafic basaltic magma. On the other hand, trondhjemites were formed in Archean, with the source from partial melting of Archean amphibolites and granulites under the continental Yangtze Craton in a high-pressure condition. They are composed of felsic minerals such as plagioclase, quartz, and Na-K-rich feldspar and minor mafic minerals biotite and hornblende. The ultramafic-mafic rocks exhibit a band within the K-feldspar-rich granites.The K-feldspar-rich granites are found in the southwestern of the Huangling