EOSC 114 Lecture 3: Module 3 - The Explosive Earth Volcanoes
Document Summary
Module 3: the explosive earth - volcanoes: explain what magma density and magma viscosity are. Magma: formed by melting pre-existing rock in earth"s interior, called lava when it reaches surface. Magma viscosity: ability of magma to flow, lower viscosity higher ability to flow, higher viscosity more explosive. Affected by chemical composition and temperature: chemical composition: the higher sio2 the higher viscosity (strong bond so higher resist of flown). Viscosity is proportional to weight % of sio2 in magma: temperature: when cooled more si-o bonds form increasing viscosity. Viscosity is proportional to 1/t where t = temperature: list the different categories of volcanic rocks and explain the differences between the magmas they came from. Intrusive rock: magma that cools slowly underground (in crustal magma chambers). Crystallized minerals that are large enough to see with naked eye. Extrusive rock: magma that cools on earth surface (more quickly than underground), from lava creates small size crystals too small to see with eye.
