10-3) Intrusive Igneous Activity

Question 1

what are intrusive features?

Answer 1

when magma forces its way through cracks in the upper crust but fails to reach the surface.

Question 2

what are plutons?

Answer 2

structures the underground magma forms when it cools

Question 3

where do plutons form?

Answer 3

in crust where magma cools the intrusive igneous rocks

Question 4

what are sills and laccoliths?

Answer 4

plutons that form when magma intrudes between rock layers close to the surface then harden.

Question 5

how do sills form?

Answer 5

when magma squeezes between horizontal layers of sedimentary rock. Form in shallow depths, less pressure. Allows magma to lift underlying rock so magma can squeeze in

Question 6

how do laccoliths form?

Answer 6

lens-shaped pluton has pushed the overlying rock layers upward.
Magma has a higher viscosity compared to sills, collects in a mass that bulges upward

Question 7

what are dikes?

Answer 7

plutons that forms when magma from magma chamber moves into fractures that cut upward through rock layers. doesn’t reach surface.

Question 8

what are batholiths?

Answer 8

mass of rock formed when a large body of magma cools inside Earth’s crust. surface exposure, rather thick

Question 9

what are dome mountains?

Answer 9

formed by smaller bodies of hardened magma, pushed up and layers above rock bend into a dome shape