Volcanic plateau up by foundering of the Earth's crust to form the present ocean basin. The Earth features numerous subaerial and submarine volcanic plateaus such as the Columbia River Plateau (subaerial) and the vast Ontong Java Plateau (submarine). Pyroclastic plateaus are produced by massive pyroclastic flows and they are underlain by pyroclastic rocks: agglomerates, tephra, volcanic ashes cemented into tuffs, mafic or felsic. Examples include Shirasu-Daichi which covers almost all of Southern Kyūshū, Japan and the North Island Volcanic Plateau in New Zealand. Volcanic plateau A volcanic plateau is a plateau produced by volcanic activity. There are two main types: lava plateaus
Archean felsic volcanic rocks rocks in Archean greenstone belts is between dacite to rhyolite (Table 2). In comparison, the modern felsic volcanic rock average composition (after Archean, <2.5 Ga) is similar to rhyolite, indicating a more felsic shift in felsic volcanism. However, the composition may be biased because of weathering right after deposition or metamorphism during later stages of deformation. In addition, Archean felsic volcanic rocks have high zircon abundance. Incompatible elements, like zirconium, are reluctant to substitute into early-forming crystals. So, they tend to remain in the melt. In strongly fractionated felsic magma, zircon is easily saturated. As a result, zircon is common