Arizona, Grand Canyon, Isis Temple region, southwest Bright Angel Canyon, at north side, Granite Gorge, and along Colorado River and tributary canyons
Country
United States
Type section
Named for
Shinumo Canyon
Named by
Noble
Year defined
1914[1]
The Shinumo Quartzite also known as the Shinumo Sandstone, is a Mesoproterozoic rock formation, which outcrops in the eastern Grand Canyon, Coconino County, Arizona, (Northern Arizona). It is the 3rd member of the 5-unit Unkar Group. The Shinumo Quartzite consists of a series of massive, cliff-forming sandstones and sedimentary quartzites. Its cliffs contrast sharply with the stair-stepped topography of typically brightly-colored (orange, red, yellow, etc) strata of the underlying slope-forming Hakatai Shale. Overlying the Shinumo, dark green to black, fissile, slope-forming shales of the Dox Formation create a well-defined notch. It and other formations of the Unkar Group occur as isolated fault-bound remnants along the main stem of the Colorado River and its tributaries in Grand Canyon.
Typically, the Shinumo Quartzite and associated strata of the Unkar Group dip northeast (10°–30°) toward normal faults that dip 60+° toward the southwest. This can be seen at the Palisades fault in the eastern part of the main Unkar Group outcrop area (below East Rim).[2]
The Shinumo Quartzite is a middle member of the Unkar Group. The Unkar Group is about 1,600 to 2,200 m (5,200 to 7,200 ft) thick and composed of, in ascending order, the Bass Formation, Hakatai Shale, Shinumo Quartzite, Dox Formation, and Cardenas Basalt.
The Unkar Group consists of a sequence of sedimentary rocks that accumulated in a variety of environments ranging from fluvial to shallow-marine. Overall, the strata within it are conformable with the exception of a significant disconformity between the Hakatai Shale and Shinumo Quartzite. The Unkar Group is overlain in ascending order by 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 Sixtymile Formation, about 60 m (200 ft) thick. The Unkar Group, as the base section of the Grand Canyon Supergroup, overlies deeply eroded granites, gneisses, pegmatites, and schists that comprise Vishnu Basement Rocks.[2][3][4]
^Noble, LF (1914) The Shinumo Quadrangle, Grand Canyon District, Arizona. Bulletin. no. 549. US Geological Survey, Reston, Virginia. 100 pp.
^ abHendricks, JD, and GM Stevenson (2003) Grand Canyon Supergroup: Unkar Group. In SS Beus and M Morales, eds., pp. 39–52, Grand Canyon Geology, 2nd ed. Oxford University Press, New York.
^Elton, DP, and EH McKee (1982) Age and correlation of the late Proterozoic Grand Canyon disturbance, northern Arizona. Geological Society of America Bulletin. 93(8): 681–699.
^Karlstrom, KE, BR Ilg, Bradley, D Hawkins, ML Williams, G Dumond, KK. Mahan, and SA Bowring, Samuel (2012) Vishnu Basement Rocks of the Upper Granite Gorge: Continent formation 1.84 to 1.66 billion years ago. In JM Timmons and KE Karlstrom, eds., pp. 7–24, Grand Canyon geology: Two billion years of earth's history. Special Paper no 294, Geological Society of America, Boulder, Colorado.
The ShinumoQuartzite also known as the Shinumo Sandstone, is a Mesoproterozoic rock formation, which outcrops in the eastern Grand Canyon, Coconino County...
These slopes are deposited upon the cliff-forming unit of ShinumoQuartzite. The ShinumoQuartzite forms the cliff-base of Isis Temple, with highly erodable...
slopes of the Cambrian Tonto Group, and below that red shale and ShinumoQuartzite of the Proterozoic Unkar Group. Precipitation runoff from Cheops Pyramid...
Hakatai Shale also contrasts greatly with the steep cliffs formed by ShinumoQuartzite as seen at the base of Isis Temple. In the central Grand Canyon north...
members, a virtual quartzite 'mountain island' in the Tapeats Sea. (Tapeats Sandstone was deposited only around ShinumoQuartzite monadnocks.) The formation...
composed, in ascending order, of the Bass Formation, Hakatai Shale, ShinumoQuartzite, Dox Formation, and Cardenas Basalt. Units 4 & 5 are found mostly...
orange-red and gives the Red Canyon its name. ShinumoQuartzite is a resistant marine sedimentary quartzite that was eroded to form monadnocks that later...
composed of, in ascending order, the Bass Formation, Hakatai Shale, ShinumoQuartzite, Dox Formation, and Cardenas Basalt. The Unkar Group is overlain in...
composed of, in ascending order, the Bass Formation, Hakatai Shale, ShinumoQuartzite, Dox Formation, and Cardenas Basalt. The Unkar Group is overlain in...
Excalibur, and two miles east-southeast of Holy Grail Temple, within the Shinumo Amphitheater. Topographic relief is significant as it rises over 5,100...
Point, and two miles west-northwest of King Arthur Castle, within the Shinumo Amphitheater. Topographic relief is significant as it rises over 4,500...
composed, in ascending order, of the Bass Formation, Hakatai Shale, ShinumoQuartzite, Dox Formation, and Cardenas Basalt. In ascending order, the Cardenas...
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