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Rhyolite (/ ˈraɪ.əlaɪt / RY-ə-lyte) [1][2][3][4] is the most silica -rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase.
Rhyolitic lava dome of Chaitén Volcano during its 2008–2010 eruption One of the Inyo Craters, an example of a rhyolite dome Nea Kameni seen from Thera, Santorini. In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano.
Magma (from Ancient Greek μάγμα (mágma) 'thick unguent') [1] is the molten or semi-molten natural material from which all igneous rocks are formed. [2] Magma (sometimes colloquially but incorrectly referred to as lava) is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial ...
If the magma does not contain much gas, rhyolite tends to just form a lava dome, and such eruptions are more common. However, when mixed with gas or steam, rhyolitic eruptions can be extremely violent. The magma froths to form pumice and ash, which is thrown out with great force. Such eruptions tend to be earlier in any given eruption cycle.
Magma exists in three main forms that vary in composition. [3] When magma crystallizes within the crust, it forms an extrusive igneous rock. Dependent on the composition of the magma, it may form either rhyolite, andesite, or basalt. [3] Volatiles, particularly water and carbon dioxide, significantly impact the behavior of each form of magma ...
The Rockland complex formed between 825,000 and 609,000 years ago. It was the source of lava domes and lava flows of dacitic composition. Around 610,000 years ago over 130 km 3 [19] of rhyolite magma violently
Magma rich in silica and poor in dissolved water is most easily cooled rapidly enough to form volcanic glass. As a result, rhyolite magmas, which are high in silica, can produce tephra composed entirely of volcanic glass and may also form glassy lava flows. [2] Ash-flow tuffs typically consist of countless microscopic shards of volcanic glass. [3]
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. [1] 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 ...