English: Grand Canyon, Bright Angel Canyon at Granite Gorge.

(view north)--The southwest section of Br. Angel Can, south of Phantom Creek is a sub-fault section, upside-to-the-west normal fault (but a small 3-sub fault block). The lowest 4 members of the (6-member) Unkar Group, upon Vishnu Schist, occur in this uplifted "en:horst-type" section. The Unkar Group is geologically paleo-deposited at an angular unconformity, dipped about 15 degrees. The top of the layers, were eroded to flatness, by an erosion unconformity, but the erosion resistant Shinumo Quartzite, was an "island", with Tapeats Sandstone, laid only around the island perimeter. (shown in other parts of the photo, up the Bright Angel Canyon, for instance); the erosion unconformity is named, the en:Great Unconformity, also found at other selected locales in Arizona; also south Nevada. (The 6-unit Unkar Group for example, is a "conformity", with no erosional sequences, interspersed.)