viscosity
The internal resistance to flow
Pluton
An intrusive igneous rock boundary formed when minerals formed from cooling magma combine over a really really long time. Can be exposed at earth’s surface due to erosion and uplift. Classified according to size, shape, and relationship with surrounding rocks
Batholith
The largest plutons. Common in major mountain chains.
Stock
An irregularly shaped pluton smaller than a batholith but similar to it
Laccolith
A mushroom shaped pluton with round top and flat bottom. Up to sixteen km wide.