Lava Vesuvius between May 14 and June 4, 1737. Serao described "a flow of fiery lava" as an analogy to the flow of water and mud down the flanks of the volcano following heavy rain. The composition of almost all lava of the Earth's crust is dominated by silicate minerals, mostly feldspars, olivine, pyroxenes, amphiboles, micas and quartz. Igneous rocks, which form lava flows when erupted, can be classified into three chemical types: "felsic", "intermediate", and "mafic" (four if one includes the super-heated "ultramafic"). These classes are primarily chemical, however, the chemistry of lava also tends to correlate with the magma
Geology of the Northwest Territories metavolcanic rocks. Quartz arenite in the Rae Craton has been interpreted as possible passive margin or rift deposits. Around the world, greenstone belts are a hallmark of ancient Precambrian rocks. The Ennadai-Rankin greenstone belt is the second largest in Canada and displays felsic volcanic and volcaniclastic rocks, as well as mafic rocks reaching greenschist grade on the sequence of metamorphic facies. Laminations in ironstone and pelite formations suggest that the mafic volcanic rocks deposited on the low energy slope of a volcanic plateau, away from wave action. Because of the enormous time distance from the Archean, exact interpretations are less