Here are two examples (on opposite sides of the world) of places where a dark-colored host rock has been intensely fractured (maybe even "shattered") and then felsic magma squirted into and filled those fractures, solidifying into granite. In the first example, differential weathering has etched away the less stable dark-colored minerals of the host rock, exposing the more-stable granite dikes in high relief. I like the high contrast between host rock and intrusion, and the visual similarity between these two far-flung locations experiencing the same geologic process. That's uniformitarianism for you.

Lake Manapouri, near Te Anau town, southern South Island, New Zealand.

Photo by Andrew Birch.

Georgetown Intrusive Suite, exposed on Rock Creek Parkway, Washington, D.C.

Photo by Callan Bentley.

Labels: geology, granite