What's the Difference Between a Sill and a Laccolith?

If it runs parallel to rock layers, it is called a sill. A sill is concordant with existing layering, and a dike is discordant. ... If an intrusion makes rocks above rise to form a dome, it is called a laccolith. A laccolith is a sill-like body which has expanded upward by deforming the overlying rock.

How can you tell a dike from a sill?

1. Dykes (or dikes) are igneous rocks that intrude vertically (or across), while sills are the same type of rocks that cut horizontally (or along) in another land or rock form. 2. Dykes are discordant intrusions, while sills are concordant intrusions.

Is a sill a pluton?

Pluton, body of intrusive igneous rock the size, composition, shape, or exact type of which is in doubt; when such characteristics are known, more limiting terms can be used. Thus, plutons include dikes, laccoliths, batholiths, sills, and other forms of intrusions.