| A | B |
|---|
| volcano | (1) A vent from which melt from inside the Earth spews out onto the planet’s surface; (2) a mountain formed by the accumulation of extrusive volcanic rock. |
| magma | Molten rock beneath the Earth’s surface. |
| lava | Molten rock that has flowed out onto the Earth’s surface. |
| extrusive igneous rock | Rock that forms by the freezing of lava above ground, after it flows or explodes out (extrudes) onto the surface and comes into contact with the atmosphere or ocean |
| partial melt | The melting in a rock of the minerals with the lowest melting temperatures, while other minerals remain solid. |
| viscosity | The resistance of material to flow |
| fractional crystallization | The process by which a magma becomes progressively more silicic as it cools, because early-formed crystals settle out. |
| dike | A tabular (wall-shaped) intrusion of rock that cuts across the layering of country rock |
| sill | A nearly horizontal tabletop-shaped tabular intrusion that occurs between the layers of country rock. |
| plutons | An irregular or blob-shaped intrusion; can range in size from tens of m across to tens of km across. |
| rock cycle | the succession of events that results in the transformationof earth materials from one type to another, then another and so on |
| Silicic | Rich in silica with relitivly little iron and magnesium |
| Shield Volcano | a subarial volcano with a broad, gentle dome, formed either from low viscosity basaltic lava or from large pryoclastic sheets |
| mafic | a term used in reference to magmas or igneauos rocks hat are relatively poor in silica and rich in iron and magnesium |
| intrusive | rock formed by the freezing of magma underground |
| caldera | a large circular depression with steep walls and a fairly flat floor, formed after an eruption as the center of the volcano collapses into the drained magma |
| bowens reaction series | the sequence in which different sillicate minerals crystalize during the progressive cooling of a melt |
| batholith | a vast composite intrusive igneaous rock body up to several hundred km long and 100km wide, formed by the intrusion of numerous plutons in the same region |
| Volcanic rock | is a rock formed from magma erupted from a volcano. |
| magma assimilition | is the process of magmatic differentiation whereby ascending magmas evolve chemically by recruiting easily melted or dissolved components (fusibles) from the walls of their conduits. |
| Lava plateau | is a plateau produced by volcanic activity. There are two main types: lava plateaus and pyroclastic plateaus. |
| Volcanic pipes | are subterranean geological structures formed by the violent, supersonic eruption of deep-origin volcanoes. |
