Rhyolitic magma - SiO2 65-75%, low in Fe, Mg, Ca, high in K, Na.Viscosity modifiers are a component of most modern engine oils. Andesitic magma - SiO2 55-65 wt%, intermediate. Three general types are recognized: Basaltic magma - SiO2 45-55 wt%, high in Fe, Mg, Ca, low in K, Na.
Helens and Mount Rainier round out the top three slots. In the wake of its recent fiery rampage, it’s perhaps no surprise that Kīlauea in Hawaii tops the list as the most dangerous volcano in the U.S., according to newly released rankings from the U.S. Cinder cones are the simplest type of volcano. Geologists generally group volcanoes into four main kinds-cinder cones, composite volcanoes, shield volcanoes, and lava domes. Higher SiO2 (silica) content magmas have higher viscosity than lower SiO2 content magmas (viscosity increases with increasing SiO2 concentration in the magma). Viscosity depends on primarily on the composition of the magma, and temperature. Viscosity of Magmas Viscosity is the resistance to flow (opposite of fluidity). The amount of dissolved gases in the magma can also affect it’s viscosity, but in a more ambiguous way than temperature and silica content. Magmas that have a high silica content will therefore exhibit greater degrees of polymerization, and have higher viscosities, than those with low-silica contents. Eruptions are explosive due to the thick, highly viscous lava that is produced by composite cone volcanoes. Composite volcanoes, sometimes known as strato volcanoes, are steep sided cones formed from layers of ash and flows. There are three main types of volcano – composite or strato, shield and dome. Higher temperatures will correspond to higher average kinetic energies and faster moving molecules. The other factors that affect viscosity are temperature and the shape of the molecule. For liquids, typically the larger the intermolecular forces (IMF) the higher the viscosity. An example of high viscosity lava is felsic lava, like rhyolite or dacite. This flows out for great distances creating shield volcanoes or flood basalt fields. This flows quickly out of a volcano at a temperature of about 950 degrees Celsius. A fluidwith large viscosity resists motion because its molecular makeup gives it a lot of internal friction.Īn example of a low viscosity (fast flowing) lava is basaltic lava. It describes the internal friction of a moving fluid. Viscosity is a measure of a fluid’s resistance to flow. If I fill the same cup with water, for example, the cup will drain much more quickly.
Shield volcanoes are almost exclusively basalt, a type of lava that is very fluid when erupted. The Hawaiian shield volcanoes are the most famous examples. Shield volcanoes are the largest volcanoes on Earth that actually look like volcanoes (i.e. One of the main reasons for the high viscosity in rhyolitic magma is that it contains a What type of volcanoes are the highest? Which type of volcano has the highest viscosity magma?Īnswer and Explanation: The magma that has the highest viscosity is rhyolitic magma. 10 What are the three main types of magma?.3 What is the viscosity of basaltic lava?.1 which type of volcano has the highest viscosity magma?.
0 kommentar(er)
