ENVR 1104 Chapter Notes -Pyroxene, Oceanic Crust, Magma Chamber
13 Feb 2014
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Document Summary
Chapter 6: volcanoes; tectonic environments and eruptions: magma = melted rock- less dense than other rocks; making it often rise to the surface, lava = magma that has escaped to the earth"s surface, rock melts by: Increasing temperature of rock near its melting point. Decreasing pressure on plastic asthenosphere, near its melting point. Addition of water (steam) to rock, decreases its melting temperature: magma chamber: Rising magma accumulates within the earth"s crust. Some of the magma may form volcanic eruptions to form volcanic cones, or lava flows. Volatiles= dissolved gas content of a magma: quantity of dissolved gases affects eruptive style (quiet vs. violent, chemistry of gases released during eruption affects health and climate impacts. Viscosity is the lowest of the three magma types. The gas bubbles can move freely, find neighboring bubbles, and grow larger. Larger bubbles can lift larger chunks of magma out of the top of the volcano.
