| Tapeats Sandstone | |
|---|---|
| Stratigraphic range: Middle Cambrian [1][2] | |
 Muav Limestone-(greenish, slope-forming) and Bright Angel Shale, resting on Tapeats and the Tonto Platform, inner canyon, Granite Gorge (the two units are easily seen below the red-stained Redwall Limestone) (220 m (720 ft) thick) | |
| Type | Geological formation |
| Unit of | Tonto Group |
| Underlies | Bright Angel Shale |
| Overlies | Vishnu Basement Rocks, Unkar Group, Nankoweap Formation, Chuar Group, and Sixtymile Formation |
| Thickness | 70 m (230 ft) |
| Lithology | |
| Primary | sandstone and conglomerate |
| Other | conglomeratic sandstone |
| Location | |
| Region | northern Arizona (Grand Canyon), central Arizona, southeast California, southern Nevada, and southeast Utah |
| Country | United States of America |
| Type section | |
| Named for | Tapeats Creek[3] |
| Named by | Noble (1914)[3] |
Except where underlain by the Sixtymile Formation, the Tapeats Sandstone is the Cambrian geologic formation that is the basal geologic unit of the Tonto Group. Typically, it is also the basal geologic formation of the Phanerozoic strata exposed in the Grand Canyon, Arizona, and parts of northern Arizona, central Arizona, southeast California, southern Nevada, and southeast Utah. The Tapeats Sandstone is about 70 m (230 ft) thick, at its maximum. The lower and middle sandstone beds of the Tapeats Sandstone are well-cemented, resistant to erosion, and form brownish, vertical cliffs that rise above the underlying Precambrian strata outcropping within Granite Gorge (Inner Gorge). They form the edge of the Tonto Platform. The upper beds of the Tapeats Sandstone form the surface of the Tonto Platform. The overlying soft shales and siltstones of the Bright Angel Shale underlie drab-greenish slopes that rise from the Tonto Platform to cliffs formed by limestones of the Muav Limestone and dolomites of the Frenchman Mountain Dolostone.[2][4][5]
- ^ Cite error: The named reference
KarlstromOther2018awas invoked but never defined (see the help page). - ^ a b Karlstrom, K.E., Mohr, M.T., Schmitz, M.D., Sundberg, F.A., Rowland, S.M., Blakey, R., Foster, J.R., Crossey, L.J., Dehler, C.M. and Hagadorn, J.W., 2020. Redefining the Tonto Group of Grand Canyon and recalibrating the Cambrian time scale. Geology, 48(5), pp. 425–430.
- ^ a b Noble, LF (1914) The Shinumo quadrangle, Grand Canyon district, Arizona. Bulletin no. 549, US Geological Survey, Reston, Virginia. 42 pp.
- ^ Connors, T.B., Tweet, J.S., and Santucci, V.L., 2020. Stratigraphy of Grand Canyon National Park. In: Santucci, V.L., Tweet, J.S., ed., pp. 54–74, Grand Canyon National Park: Centennial Paleontological Resource Inventory (Non-sensitive Version) . Natural Resource Report NPS/GRCA/NRR—2020/2103. National Park Service, Fort Collins, Colorado, 603 pp.
- ^ Cite error: The named reference
BeusOthers1989awas invoked but never defined (see the help page).