Muav Limestone
The Muav Limestone is a Cambrian geologic formation within the 5-member Tonto Group. It is a thin-bedded, gray, medium to fine-grained, mottled dolomite; coarse- to medium-grained, grayish-white, sandy dolomite and grayish-white, mottled, fine-grained limestone. It also contains beds of shale and intraformational conglomerate. The beds of the Muav Limestone are either structureless or exhibit horizontally laminations and cross-stratification. The Muav Limestone forms cliffs or small ledges that weather a dark gray or rusty-orange color. These cliffs or small ledges directly overlie the sloping surfaces of the Bright Angel Shale. The thickness of this formation decreases eastward from 250 feet (76 m) in the western Grand Canyon to 45 feet (14 m) in the eastern Grand Canyon. To the west in southern Nevada, its thickness increases to 830 feet (250 m) in the Frenchman Mountain region.
| Muav Limestone | |
|---|---|
| Stratigraphic range: Middle Cambrian | |
representative sequence of Redwall Limestone, Temple Butte Formation, and Muav Limestone, in Grand Canyon | |
| Type | Geological formation |
| Unit of | Tonto Group |
| Underlies | either the Frenchman Mountain Dolostone (Cambrian) or Redwall Limestone (Mississippian). Locally underlies Temple Butte Formation (Devonian) that fills narrow paleovalleys cut into the Muav Limestone. |
| Overlies | Bright Angel Shale |
| Thickness | 830 feet (250 m), at maximum |
| Lithology | |
| Primary | limestone and dolomite |
| Other | shale and intraformational conglomerate. |
| Location | |
| Region | Northern Arizona (Grand Canyon), central Arizona, southeast California, southern Nevada, and southeast Utah |
| Country | United States of America |
| Type section | |
| Named for | Muav Canyon, north side of Colorado River |
| Named by | Noble (1914) |
Beyond the Grand Canyon area, the Muav Limestone is recognized in southern Utah, southern Nevada and southern California. In parts of California, it is known and mapped as the Muav Marble.