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The resulting Grand Canyon Supergroup of sedimentary units is composed of nine varied geologic formations that were laid down from 1.2 billion and 740 million years ago in this sea. [11] Good exposures of the supergroup can be seen in eastern Grand Canyon in the Inner Gorge and from Desert View, Lipan Point and Moran point. [12] [note 1]
Figure 1. A geologic cross section of the Grand Canyon. [5]The Tonto Group is a name for an assemblage of related sedimentary strata, collectively known by geologists as a Group, that comprises the basal sequence Paleozoic strata exposed in the sides of the Grand Canyon.
Bass Formation(finely-layered, dark slopes), sitting on top of (base units). Vishnu Basement Rocks (black stratum) within the Granite Gorge and side canyons. The Grand Canyon Supergroup is a Mesoproterozoic to a Neoproterozoic sequence of sedimentary strata, partially exposed in the eastern Grand Canyon of Arizona.
This is a list of Supai Group prominences in the Grand Canyon. Landforms with up to 4 units of Supai Group, as prominences. The rock unit sequences are as follows: Coconino Sandstone, (prominence, Permian unit) Hermit Shale, Permian; Supai Group, (4 units, Pennsylvanian-Permian) 4 – Esplanade Sandstone, (Permian)
The Great Unconformity of Powell in the Grand Canyon is a regional unconformity that separates the Tonto Group from the underlying, faulted and tilted sedimentary rocks of the Grand Canyon Supergroup and vertically foliated metamorphic and igneous rocks of the Vishnu Basement Rocks.
All of the known outcrops are discontinuous lenses up to several tens of meter thick and from a few tens of meters to nearly a kilometer wide. Nowhere does this formation occur as a single, continuous sheet, as do all of the other sedimentary rock units of Paleozoic age in the Grand Canyon. The Surprise Canyon Formation exposures are commonly ...
The Vishnu Basement Rocks is the name recommended for all Early Proterozoic crystalline rocks (metamorphic and igneous) exposed in the Grand Canyon region. They form the crystalline basement rocks that underlie the Bass Limestone of the Unkar Group of the Grand Canyon Supergroup and the Tapeats Sandstone of the Tonto Group .
The Middle Permian Toroweap Formation is a thin, darker geologic unit, between the brighter colored units of the Kaibab Limestone above, and Coconino Sandstone below. It is a prominent unit in Grand Canyon, Arizona, Southwestern United States, found through sections of the South Rim, Grand Canyon, and the North Rim, of the Kaibab Plateau; also the Kaibab's southeast extension to Cape Royal ...