What is andesitic volcano?
Andesite is a gray to black volcanic rock with between about 52 and 63 weight percent silica (SiO2). Andesite magma can also generate strong explosive eruptions to form pyroclastic flows and surges and enormous eruption columns. Andesites erupt at temperatures between 900 and 1100 ° C.
What type of volcano has andesitic lava?
Shield volcanoes are formed by basaltic magma, typically above a mantle plume, whereas the stratovolcanoes (sometimes referred to as composite volcanoes) are formed by andesitic/rhyolitic magma.
Where does andesitic eruption occur?
Andesite commonly erupts from stratovolcanoes, where they form small-volume flows that typically advance only short distances down the flanks of a volcano. The two examples shown here are short andesite flows advancing down the slope of the Lascar volcano in Chile, and the Colima volcano in Mexico.
What causes andesitic volcanoes?
Granitic, or rhyolitic, magmas and andesitic magmas are generated at convergent plate boundaries where the oceanic lithosphere (the outer layer of Earth composed of the crust and upper mantle) is subducted so that its edge is positioned below the edge of the continental plate or another oceanic plate.
Is andesitic magma high in silica?
Andesitic magma — SiO2 55-65 wt%, intermediate. in Fe, Mg, Ca, Na, K. Rhyolitic magma — SiO2 65-75%, low in Fe, Mg, Ca, high in K, Na.
What are the characteristics of andesitic magma?
It ranges in temperature from about 1000oC to 1200oC (1832oF to 2192oF). Andesitic magma has moderate amounts of these minerals, with a temperature range from about 800oC to 1000oC (1472oF to 1832oF). Rhyolitic magma is high in potassium and sodium but low in iron, magnesium, and calcium.
What is andesitic magma made from?
Andesitic magma is formed through wet partial melting of the mantle. The mantle under the ocean has contact with water. Basaltic magma with a high water content is the result. If this type of basaltic magma melts with continental crust that has a high density of dioxide silicon, andesitic magma will form.
Which of the following is an example of andesitic rock?
Andesites occur mainly as surface deposits and, to a lesser extent, as dikes and small plugs. Many of the deposits are not normal lava flows but rather flow breccias, mudflows, tuffs, and other fragmental rocks; the peperino near Rome and the trass of the Eifel district in Germany are examples.
Is andesitic lava acidic?
Andesitic magma, which is lower in temperature, has more silica and a lot of dissolved gases and is more likely to explode when it reaches the surface. Acidic lava, which is very viscous (sticky). Steep sides as the lava doesn’t flow very far before it solidifies.
What is the viscosity of andesitic?
800 to 1000oC
Basaltic magma – 1000 to 1200oC. Andesitic magma – 800 to 1000oC….Viscosity of Magmas.
|Summary Table||Magma Type||Andesitic|
|Chemical Composition||55-65 SiO2 %, intermediate in Fe, Mg, Ca, Na, K|
|Temperature||800 – 1000 oC|
What is the magma composition of a composite volcano?
Composite volcano magma is felsic, which means it contains silicate-rich minerals rhyolite, andesite, and dacite. Low-viscosity lava from a shield volcano, such as might be found in Hawaii, flows from fissures and spreads.