Types of volcanic eruptions eruptions are associated with volatile-rich dacitic to rhyolitic lavas, and occur most typically at stratovolcanoes. Eruptions can last anywhere from hours to days, with longer eruptions being associated with more felsic volcanoes. Although they are associated with felsic magma, Plinian eruptions can just as well occur at basaltic volcanoes, given that the magma chamber differentiates and has a structure rich in silicon dioxide. Plinian eruptions are similar to both Vulcanian and Strombolian eruptions, except that rather than creating discrete explosive events, Plinian eruptions form sustained eruptive columns. They are also similar to Hawaiian lava fountains in that both eruptive types
Eoarchean geology highly deformed biotite-hornblende tonalitic to granitic orthogneiss. Subordinate mafic amphibolitic and chloritic elliptical enclaves and inclusions are observed in felsic gneisses.Although the rocks are highly deformed and could not reflect the original field relation between rock units, the chemical composition of the rocks showcases how Eoarchean greenstone-TTG be like. Chemical composition in the mafic inclusion suggests the acasta area was possibly a supra-subduction setting. Dominant felsic rocks are composed of highly deformed tonalitic, granodioritic and granitic gneisses. Inclusion of as early as 4.2 billion years old zircon core are observed in the gneisses. Mafic rocks, i.e. subordinate amphibolite and ultra