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| This view along the Bright Angel Trail shows the falls, plunge pools, and erosion-polished granite along a small tributary of Pipe Creek. The Precambrian-age Vishnu Basement Rocks contains several large bodies of granitic rocks (including granite, granodiorite, pegmatite, and aplite). Zoroaster Granite is a historic name given to granitic rocks in the Granite Gorge (on Wesley Powell's original name for the Inner Gorge) and elsewhere in the region. However, these plutonic rocks (rocks that form from the cooling of igneous plutons) have a complex history and occur in various forms (small dike to great intrusive bodies) that were also subjected to mid-crustal tectonics forces and metamorphism over a long period of time (Ilg and others, 1996). |
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