| A | B |
|---|
| geology | the study of the origin, history, and structure of the earth |
| continental drift | according to Wegeners hypothesis, the continents move slowly across the earth's surface |
| magma chamber | a pocket where magma collects |
| sill | created when the crack is parallel to existing rock layers when magma hardens |
| volcanic neck | when magma hardens in a volcano's pipe |
| lithosphere | is a layer of relatively cool, rigid rock that includes the uppermost part of the mantle as well as the earth's crust |
| subduction | as sea-floor spreading occurs, old oceanic plates sink into the mantle |
| composite volcano | a volcano that forms from explosive erruptions that produce a combination of lava and ash |
| clastic rock | sedimentary rocks that form from the broken fragments |
| mineral | a naturally occuring inorganic solid with a crystal structure and a characteristic chemical composition |
| transform boundary | where plates slide past each other, moving in opposite directions |
| cinder cone | a small, steep-sided volcano resulting from an erruption entirely of ash and cinders |
| crater | a bowl-shaped pit at the top of the central vent in most volcanos |
| hardness | the resistance of a mineral to scratching |
| batholiths | the largest type of intrusive igneous rock mass |
