Question

Which statement best describes an igneous intrusion? A. Magma is exported to an open area and forms iron. B. Igneous intrusions form when ice crystals splash into lava. C. Magma explodes to the surface and forms a smooth outer layer of rock. D. Magma is injected into surrounding rock forming an igneous intrusion.

Answer 1

Igneous intrusions occur when magma is slowly forced to the surface through gaps in the surrounding layers of rock, and ends up cooling off before it reaches the surface, so D. This typically is exhibited by the rocks in question being conical and eroding to show the igneous layers beneath.