Cambrian geologic formation found in Grand Canyon, Arizona
Sixtymile Formation
Stratigraphic range: Cambrian, 527–509 Ma
PreꞒ
Ꞓ
O
S
D
C
P
T
J
K
Pg
N
[1][2]
Sixtymile Formation in Grand Canyon
Type
Geological formation
Unit of
Tonto Group[1][2]
Underlies
Tapeats Sandstone
Overlies
Chuar Group
Thickness
60 m (200 ft), at maximum
Lithology
Primary
siltstone and sandstone
Other
intraformational breccia
Location
Region
Arizona, Northern Arizona)
Country
United States
Extent
the Chuar syncline, Grand Canyon
Type section
Named by
Ford et al. (1972),[3] Ford and Breed (1973),[4] and Elston (1979)[5]
The Sixtymile Formation is a very thin accumulation of sandstone, siltstone, and breccia underlying the Tapeats Sandstone that is exposed in only four places in the Chuar Valley. These exposures occur atop Nankoweap Butte and within Awatubi and Sixtymile Canyons in the eastern Grand Canyon, Arizona. The maximum preserved thickness of the Sixtymile Formation is about 60 m (200 ft). The actual depositional thickness of the Sixtymile Formation is unknown owing to erosion prior to deposition of the Tapeats Sandstone.[6]
Sixtymile Formation and the underlying Chuar Group are preserved only in a broad asymmetric fold comprising both units, called the Chuar syncline. The Chuar Syncline is a doubly plunging fold, which means that along the hingeline within the axis of the syncline, beds in some areas (Nankoweap Canyon) dip toward the south, and in other areas (Lava Chuar Canyon), beds dip toward the north. The Sixtymile Formation, Chuar Group, and Chuar Syncline is bounded on the east by the Butte fault zone and on all other sides by the overlying Tapeats Sandstone. The hingeline of the Chuar Syncline parallels the trace of the Butte fault, suggesting a genetic relationship between the syncline and the fault.[6]
In descending order, the Sixtymile Formation is underlain by the Chuar Group, Nankoweap Formation, and the Unkar Group. The Unkar Group lies unconformably upon deeply eroded granites, gneisses, pegmatites, and schists of the Vishnu Basement Rocks. The Nankoweap and Sixtymile formations together with the Chuar and Unkar groups comprise the Grand Canyon Supergroup.[6]
^ abCite error: The named reference KarlstromOthers2018a was invoked but never defined (see the help page).
^ abCite error: The named reference KarlstromOthers2020a was invoked but never defined (see the help page).
^Ford, TD, WJ Breed, and JW Mitchell (1972) Name and age of the upper Precambrian basalts in the eastern Grand Canyon. Geological Society of America Bulletin. 83(1):223–226.
^Ford, TD, and WJ Breed (1973) Late Precambrian Chuar Group, Grand Canyon, Arizona. Geological Society of America Bulletin. 84(4):1243–1260.
^Elston, DP (1979) Late Precambrian Sixtymile Formation and orogeny at the top of the Grand Canyon Supergroup, northern Arizona. Professional Paper no. 1092, U.S. Geological Survey, Reston, Virginia. 20 pp.
^ abcDehler, CM, SM Porter, and JM Timmons (2012) The Neoproterozoic Earth system revealed from the Chuar Group of Grand Canyon., in JM Timmons and KE Karlstrom, eds., pp. 49–72, Grand Canyon Geology: Two Billion Years of Earth's History. Special Paper no. 489. Geological Society of America, Boulder, Colorado.
and 23 Related for: Sixtymile Formation information
The SixtymileFormation is a very thin accumulation of sandstone, siltstone, and breccia underlying the Tapeats Sandstone that is exposed in only four...
This group comprises the Unkar Group, Nankoweap Formation, Chuar Group and the SixtymileFormation, which overlie Vishnu Basement Rocks. Several notable...
groups consists of the SixtymileFormation, Tapeats Sandstone, Bright Angel Shale (or Formation), Muav Limestone (or Formation), and Frenchman Mountain...
Except where underlain by the SixtymileFormation, the Tapeats Sandstone is the Cambrian geologic formation that is the basal geologic unit of the Tonto...
accumulated within tectonic basins and coastal plains at first as the SixtymileFormation, a tan-colored sandstone with some small layers of shale. Later rising...
dunes. Below the Coconino Sandstone is slope-forming, Permian Hermit Formation, which in turn overlays the Pennsylvanian-Permian Supai Group. Further...
subdivision, the SixtymileFormation, of the Grand Canyon Supergroup. At the base of the Grand Canyon Supergroup, where it truncates the Bass Formation, the period...
Nankoweap Formation, about 113 to 150 m (371 to 492 ft) thick; the Chuar Group, about 1,900 m (6,200 ft) thick; and the SixtymileFormation, about 60 m...
the Grand Canyon Supergroup, overlain by the thin, in comparison, SixtymileFormation, the top member of the multi-membered Grand Canyon Supergroup. The...
Nankoweap Formation, about 113 to 150 m (371 to 492 ft) thick; the Chuar Group, about 1,900 m (6,200 ft) thick; and the SixtymileFormation, about 60 m...
Coconino Sandstone with a small, remnant Kaibab Limestone and Toroweap Formation caprock. The sandstone, which is the third-youngest of the strata in the...
Nankoweap Formation, about 113 to 150 m (371 to 492 ft) thick; the Chuar Group, about 1,900 m (6,200 ft) thick; and the SixtymileFormation, about 60 m...
overlays Permian Hermit Formation (reddish slope), Esplanade Sandstone (red ledges), and Wescogame and Manakacha Formations of the Pennsylvanian-Permian...
Mesoproterozoic formations in the Grand Canyon are overlain by the 850 million year old, Neoproterozoic Chuar Group and SixtymileFormation sedimentary rocks...
dunes. Below the Coconino Sandstone is slope-forming, Permian Hermit Formation, which in turn overlays the Pennsylvanian-Permian Supai Group. Further...
Below the Coconino Sandstone is reddish, slope-forming, Permian Hermit Formation, which in turn overlays the Pennsylvanian-Permian Supai Group. Further...
Global Information
Arizona, Northern Arizona)
United States