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In geology, felsic is a modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz. [1] It is contrasted with mafic rocks, which are richer in magnesium and iron. Felsic refers to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium ...
Eruptions can last anywhere from hours to days, with longer eruptions being associated with more felsic volcanoes. Although they are usually associated with felsic magma, Plinian eruptions can occur at basaltic volcanoes, if the magma chamber differentiates with upper portions rich in silicon dioxide, [40] or if magma ascends rapidly. [42]
The word lava comes from Italian and is probably derived from the Latin word labes, which means a fall or slide. [2] [3] An early use of the word in connection with extrusion of magma from below the surface is found in a short account of the 1737 eruption of Vesuvius, written by Francesco Serao, who described "a flow of fiery lava" as an analogy to the flow of water and mud down the flanks of ...
Igneous rock (igneous from Latin igneus 'fiery'), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in either a planet 's mantle or crust.
Chaos Crags is the youngest group of lava domes in Lassen Volcanic National Park, California. They formed as six dacite domes 1,100-1,000 years ago, one dome collapsing during an explosive eruption about 70 years later. The eruptions at the Chaos Crags mark one of just three instances of Holocene activity within the Lassen volcanic center.
Felsic eruption forms felsic volcanic rocks near the volcano and a spectrum of volcano-sedimentary sequence in the sea in Archean. [1] Archean felsic volcanic rocks are felsic volcanic rocks that were formed in the Archean Eon (4 to 2.5 billion years ago). [2] The term "felsic" means that the rocks have silica content of 62–78%. [3]
The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic magma, which is high in magnesium and iron and produces basalt or gabbro, as it fractionally crystallizes to become a felsic magma, which is low in ...
Alkaline basalt, lesser hawaiite and basanite magmas from effusive eruptions create the massive shield volcanoes and small cinder cones throughout the volcanic province, several of which comprise lherzolite magma. [3] Felsic magmas from more viscous eruptions create the massive central volcanoes and largely consist of trachyte, pantellerite and ...