A large intrusion of magma that forms over a long period of time deep under the Earth has 128 square kilometers exposed to the surface by erosion. Analysis proves that the rock contains large crystals of gabbro. This formation is called
A) a stock.
B) a batholith.
C) a dike.
D) a sill.

Question

Quizplus · Accepted Answer

A large intrusion of magma that forms over a long period of time deep under the Earth and covers an area of more than 100 square kilometers is called a batholith. The presence of large crystals of gabbro indicates that the intrusion cooled slowly, allowing the crystals to grow to a large size. Dikes and sills are smaller intrusions and typically do not have such large crystals. A stock is a small, circular intrusion.

A Large Intrusion of Magma That Forms Over a Long