intro_to_geo_10

intro_to_geo_10 - Volcanic rocks cont Stratovolcanoes Also...

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Volcanic rocks cont. Stratovolcanoes Also known as composite volcanoes, are large, conic volcanoes The walls of stratovolcanoes are comprised of alternating layers of tephra and lava rock Stratovolcanoes are the result of multiple eruptions, which have in turn produced both effusive lava and explosive pyroclastics whereas the smaller cinder cones represent single volcanic events The high viscosity of andesitic lava yields the steep slope of stratovolcanoes Explosivity Explosive eruptions are the result of sudden release of accumulated gas pressure within the volcano Lavas with high proportions of volatiles, such as water vapor, produce explosive eruptions in which the lava is blasted upward by explosively expanding gas, forming pyroclastic debris out of the lava that would otherwise have flowed down the slope of the volcano Hot spot eruption At the base of the mantle (core-mantle boundary) a body of mantle material may become so heated that it will rise up relative to cooler, denser surroundings
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intro_to_geo_10 - Volcanic rocks cont Stratovolcanoes Also...

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