A. Pegmatite intruding gneiss, Death Valley, CA.
B. Granite intruding gneiss, Rocky Mountain National Park, Colorado.
* May show small-scale intrusions (apophyses) into country rock. Photo A, above. Click here for another example.
* May show inclusions of country rock.
* Intruding rock may display chilled margins.
* Country rock may display hornfels texture or have otherwise "baked" appearance.
* Zone may show high degree of hydrothermal alteration.
To see a variety of intrusive contacts, click here.
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