Rocky Mountain Foreland Areas
Typically, the old Precambrian basement is described as "granite" in sample descriptions of wells that have penetrated the basement. Actually, the basement is a variety of igneous and metamorphic rocks. Intrusive relations can be seen in areas, and dikes can be readily mapped on aerial photograph- Landsat images. Schists, gneisses, amphibolites, and other such rocks make up the general basement "complex."