Which type of instructive feature forms when magma is injected into fractures the cut across rock layers?

The instructive feature that forms when magma is injected into fractures that cut across rock layers is called a "dike." Dikes are typically vertical or steeply inclined and can vary in thickness, often cooling quickly as they intrude into the surrounding rock. They are formed when magma forces its way into existing cracks, solidifying as it cools and creating a distinct geological feature.