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Because dacite is the main type of lava erupted from Mount Garibaldi, lava flows are a low to moderate hazard. [3] Dacite is felsic [ d ] in composition, containing 62–69% silica content. [ 71 ] [ 72 ] This high percentage in silica content increases the viscosity of dacitic melts relative to that of andesite or basalt , generally resulting ...
As a result of this fluidity, the peralkaline felsic lava flows were able to form small-scale folds and 1-to-2-metre-diameter (3.3-to-6.6-foot) lava tubes. The liquidus temperatures of these flows were in excess of 1,200 degrees Celsius (2,190 degrees Fahrenheit) with viscosities as low as 100,000 poise .
The Greenstone Flow is one of the world's largest known lava flows, estimated at a volume ~1650 to ~6000 cubic kilometers of mafic lava. [2] [3] In places, the lava pooled to depth of 487 meters. [4] The flow was generated by a flood basalt eruption during the Midcontinental Rift, which occurred 1.1 billion years ago. [5]
[37] [38] It has been estimated that the Ginkgo flow advanced 500 km in six days (a rate of advance of about 3.5 km per hour). [37] The lateral extent of a flood basalt flow is roughly proportional to the cube of the thickness of the flow near its source. Thus, a flow that is double in thickness at its source can travel roughly eight times as ...
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 ...
Dacite and rhyolite lavas are normally too viscous to flow away from a volcanic vent, resulting in the formation of lava domes. [25] An exception is the 15-kilometre-long (9.3-mile) Ring Creek dacite lava flow from Opal Cone on the southeastern flank of Mount Garibaldi, a length that is normally attained by basaltic lava flows. [19]
Rootless cones are formed by steam explosions as flowing hot lava crosses over a wet surface, such as a swamp, a lake, or a pond. The explosive gases break through the lava surface in a manner similar to a phreatic eruption , and the tephra builds up crater-like forms which can appear very similar to real volcanic craters.
Mount Ararat, Turkey Homa Mountain, Kenya in 1994 An eruption of Pacaya, Guatemala in 1976 Mount Banahaw, Luzon, the Philippines in 1989 Kelimutu, Flores, Indonesia. A complex volcano, also called a compound volcano or a volcanic complex, is a mixed landform consisting of related volcanic centers and their associated lava flows and pyroclastic rock. [1]