Muav Limestone | |
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Stratigraphic range: Middle Cambrian [1] | |
![]() representative sequence of Redwall Limestone, Temple Butte Formation, and Muav Limestone, in Grand Canyon | |
Type | Geological formation |
Unit of | Tonto Group[2] |
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 | 250 m (820 ft), 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[3] |
Named by | Noble (1914)[3] |
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 76 m (249 ft) in the western Grand Canyon to 14 m (46 ft) in the eastern Grand Canyon. To the west in southern Nevada, its thickness increases to 250 m (820 ft) in the Frenchman Mountain region.[2][4]
Beyond the Grand Canyon area, the Muav Limestone is recognized in southern Utah, southern Nevada and southern California.[5] In parts of California, it is known and mapped as the Muav Marble.[6]