GEOG 1350 Lecture Notes - Lecture 3: Volcanic Crater, Lava Dome, Volcanic Rock
Document Summary
Magma - hot fluid or semifluid material below or within the earth"s crust from which lava and other igneous rock is formed by cooling. Lava - hot molten or semifluid rock erupted from a volcano or fissure. Decompression melting - involves the upward movement of the earth"s mantle to an area of lower pressure. The reduction in overlying pressure enables the rock to melt, leading to magma formation. Volatiles - low boiling points that are associated with a planet"s or moon"s crust or atmosphere ie) nitrogen, carbon dioxide, and ammonia. Silica - a hard, unreactive, colorless compound that occurs as the mineral quartz and as a principal constituent of sandstone and other rocks. Tephra - rock fragments and particles ejected by a volcanic eruption. Pyroclastic material - cloud of ash, lava fragments carried through the air, and vapor - very deadly.