For the geologic fault of west Grand Canyon with the same name, see Toroweap Fault.
The Middle PermianToroweap Formation is a thin, darker geologic unit, between the brighter colored units of the Kaibab Limestone above, and Coconino Sandstone below. It is a prominent unit in Grand Canyon, Arizona, USA, found through sections of the South Rim, Grand Canyon, and the North Rim, of the Kaibab Plateau; also the Kaibab's southeast extension to Cape Royal, the Walhalla Plateau. The Colorado River of the Grand Canyon makes its excursion from due-south to due-west around the Walhalla Plateau, as it enters the east end of the Grand Canyon's interior, Granite Gorge. The formation is also found in southeast Utah.
Grand Canyon, North & South Rims, northeast Arizona, southeast Utah
The Toroweap Formation is a darker unit of gypsum and shale;[1] also sandstone. In photos the cliff-forming Kaibab and Coconino units, show the more erodable Toroweap Formation slope-forming accumulations upon the underlying Coconino Sandstone; likewise below the Coconino, the softer Hermit Formation is shown forming slopes, above the slope forming 'redbeds' of the Supai Group. Close-up views of the Toroweap will show the resistant sandstone sub-units as erosion resistant sections.
Marine transgression, and continental wind-blown sand, laid down the three units of Kaibab, Toroweap, and Coconino. The oceanic sea came from the west, and receded and re-transgressed. The Coconino Sandstone being made of sand dunes, continental, means that near-shore Toroweap deposits, and off-shore Kaibab Limestone, can all have the same actual ages in different regions where they were deposited, (continental, near-shore, open sea). In Arizona, the Toroweap formation is found in two transgressions eastwards,[3] with easternmost 'strand-lines' locating the shoreline, Toroweap west, and Coconino sand dunes or beach deposits, east.
View from the Toroweap Overlook in the Grand Canyon at sunrise.
Halfway through the Grand Canyon (north side of Colorado River), at Toroweap Valley, with Toroweap Lake (a playa lake), an outcrop, or point overlooks the West Grand Canyon section. It is the site of the Toroweap Fault. Nine miles to the west is the roughly parallel Hurricane Fault (of Hurricane Cliffs, of Arizona/Utah), the west fault, of the Uinkaret Mountains (Mount Trumbull Wilderness). An eastern fault section separates here, and goes north into Utah, passing the west side of the Kanab Plateau.
The Toroweap Overlook lies above the erosion resistant Tapeats Sandstone, near its west terminus in Grand Canyon. Southeast, across the river The Esplanade-(a regional section) is created, upon the erosion resistant Esplanade Sandstone, a resistant member of the Supai Group, (a unit above the Tapeats, but occurs on both the downside block, and upside block in the south side of the canyon, Colorado River); (The Esplanade is just upstream, with the Toroweap Fault forming its west flank). The Toroweap Overlook was visited in the 1800s by original photographers of the Grand Canyon.
Geologic sequence
The Permian geologic sequence common in the Grand Canyon:[4]
Toroweap Formation in Walnut Canyon, east of Flagstaff, Arizona Darker middle section is Toroweap: above: (3): Kaibab Limestone; below: (1): Coconino Sandstone (showing fossil dunes)-(note erosion of dunes compared to horizontal bedding of Kaibab Limestone)
^ abLucchitta, 2001. Hiking Arizona's Geology, "Hike 3: Tanner Trail", pp. 78–82, p. 78.
^Arizona Road & Recreation Atlas, Benchmark Maps, pp. 28–29, 62–63.
^Chronic, 1983. Roadside Geology of Arizona, Kaibab-Toroweap-Coconino, 2 wedge-(trangressions) graphic (unnumbered, untitled): In mid-Permian time, a desert of windblown sand swept northern Arizona, creating the Coconino Sandstone (1). Then shallow Kaibab and Toroweap seas advanced from the west, each depositing a wedge of marine limestone bordered with nearshore sandstone, siltstone, and gypsum (2). Desert conditions still prevailed on the shores, so dune sandstone there is of the same age as the marine limestones and nearshore deposits., p. 207.
^Chronic, 1983. Roadside Geology of Arizona, graphic: Stratigraphic section of Paleozoic formations of the Colorado Plateau, p. 179.
General sources
Arizona DeLorme Atlas & Gazetteer, 5th Edition, c. 2002, 76 pages, pp. 23, 24, 31, 32.
Arizona Road & Recreation Atlas, Benchmark Maps, 2nd Edition, c. 1998, pp. 28–29, 62–63.
Chronic, Halka. Roadside Geology of Arizona, c. 1983, 23rd printing, Mountain Press Publishing Co. 322 pages. pp. 229–232. (US 89A Marble Canyon – Fredonia), pp. 179–180. (softcover, ISBN978-0878421473)
Lucchitta, 2001. Hiking Arizona's Geology, Ivo Lucchitta, c 2001, Mountaineers's Books. (softcover, ISBN0898867304)
External links
Wikimedia Commons has media related to Toroweap Formation, Toroweap Formation slopes, Toroweap Formation bedding, Toroweap Point and Toroweap Overlook.
January 25, 2023
toroweap, formation, geologic, fault, west, grand, canyon, with, same, name, toroweap, fault, middle, permian, thin, darker, geologic, unit, between, brighter, colored, units, kaibab, limestone, above, coconino, sandstone, below, prominent, unit, grand, canyon. For the geologic fault of west Grand Canyon with the same name see Toroweap Fault The Middle Permian Toroweap Formation is a thin darker geologic unit between the brighter colored units of the Kaibab Limestone above and Coconino Sandstone below It is a prominent unit in Grand Canyon Arizona USA found through sections of the South Rim Grand Canyon and the North Rim of the Kaibab Plateau also the Kaibab s southeast extension to Cape Royal the Walhalla Plateau The Colorado River of the Grand Canyon makes its excursion from due south to due west around the Walhalla Plateau as it enters the east end of the Grand Canyon s interior Granite Gorge The formation is also found in southeast Utah Toroweap FormationStratigraphic range Early Permian 272 270 Ma PreꞒ Ꞓ O S D C P T J K Pg N Toroweap formation in Grand Canyon National ParkTypeGeological formationUnderliesKaibab Limestone Permian Grand Canyon North Rim Kaibab Plateau also South Rim and elsewhere in Arizona Utah NevadaOverliesCoconino SandstoneThickness200 feet 61 m approximate maximumLithologyPrimarygypsum amp shale 1 also sandstoneLocationRegion southwest Colorado Plateau Northern Arizona southeast UtahExtentGrand Canyon North amp South Rims northeast Arizona southeast UtahThe Toroweap Formation is a darker unit of gypsum and shale 1 also sandstone In photos the cliff forming Kaibab and Coconino units show the more erodable Toroweap Formation slope forming accumulations upon the underlying Coconino Sandstone likewise below the Coconino the softer Hermit Formation is shown forming slopes above the slope forming redbeds of the Supai Group Close up views of the Toroweap will show the resistant sandstone sub units as erosion resistant sections Cliffs of the Toroweap Formation can be found in Walnut Canyon National Monument about 70 mi 2 southeast of the Grand Canyon and east of Flagstaff Arizona Marine transgression and continental wind blown sand laid down the three units of Kaibab Toroweap and Coconino The oceanic sea came from the west and receded and re transgressed The Coconino Sandstone being made of sand dunes continental means that near shore Toroweap deposits and off shore Kaibab Limestone can all have the same actual ages in different regions where they were deposited continental near shore open sea In Arizona the Toroweap formation is found in two transgressions eastwards 3 with easternmost strand lines locating the shoreline Toroweap west and Coconino sand dunes or beach deposits east Contents 1 Toroweap Overlook 2 Geologic sequence 3 See also 4 References 4 1 Citations 4 2 General sources 5 External linksToroweap Overlook EditMain article Toroweap Overlook View from the Toroweap Overlook in the Grand Canyon at sunrise Halfway through the Grand Canyon north side of Colorado River at Toroweap Valley with Toroweap Lake a playa lake an outcrop or point overlooks the West Grand Canyon section It is the site of the Toroweap Fault Nine miles to the west is the roughly parallel Hurricane Fault of Hurricane Cliffs of Arizona Utah the west fault of the Uinkaret Mountains Mount Trumbull Wilderness An eastern fault section separates here and goes north into Utah passing the west side of the Kanab Plateau The Toroweap Overlook lies above the erosion resistant Tapeats Sandstone near its west terminus in Grand Canyon Southeast across the river The Esplanade a regional section is created upon the erosion resistant Esplanade Sandstone a resistant member of the Supai Group a unit above the Tapeats but occurs on both the downside block and upside block in the south side of the canyon Colorado River The Esplanade is just upstream with the Toroweap Fault forming its west flank The Toroweap Overlook was visited in the 1800s by original photographers of the Grand Canyon Geologic sequence EditThe Permian geologic sequence common in the Grand Canyon 4 4 Kaibab Limestone 3 Toroweap Formation 2 Coconino Sandstone 1B Hermit Formation 1A Esplanade Sandstone also considered upper unit of Supai Group Pennsylvanian Permian boundary North Rim Grand Canyon 4 Permian formations 4 Kaibab Limestone 3 Toroweap Formation 2 Coconino Sandstone 1 Hermit Formation X upon Supai Group redbeds Toroweap Formation in Walnut Canyon east of Flagstaff Arizona Darker middle section is Toroweap above 3 Kaibab Limestone below 1 Coconino Sandstone showing fossil dunes note erosion of dunes compared to horizontal bedding of Kaibab Limestone See also EditGeology of the Grand Canyon area Stratigraphy Marine transgressionReferences EditCitations Edit a b Lucchitta 2001 Hiking Arizona s Geology Hike 3 Tanner Trail pp 78 82 p 78 Arizona Road amp Recreation Atlas Benchmark Maps pp 28 29 62 63 Chronic 1983 Roadside Geology of Arizona Kaibab Toroweap Coconino 2 wedge trangressions graphic unnumbered untitled In mid Permian time a desert of windblown sand swept northern Arizona creating the Coconino Sandstone 1 Then shallow Kaibab and Toroweap seas advanced from the west each depositing a wedge of marine limestone bordered with nearshore sandstone siltstone and gypsum 2 Desert conditions still prevailed on the shores so dune sandstone there is of the same age as the marine limestones and nearshore deposits p 207 Chronic 1983 Roadside Geology of Arizona graphic Stratigraphic section of Paleozoic formations of the Colorado Plateau p 179 General sources Edit Arizona DeLorme Atlas amp Gazetteer 5th Edition c 2002 76 pages pp 23 24 31 32 Arizona Road amp Recreation Atlas Benchmark Maps 2nd Edition c 1998 pp 28 29 62 63 Chronic Halka Roadside Geology of Arizona c 1983 23rd printing Mountain Press Publishing Co 322 pages pp 229 232 US 89A Marble Canyon Fredonia pp 179 180 softcover ISBN 978 0878421473 Lucchitta 2001 Hiking Arizona s Geology Ivo Lucchitta c 2001 Mountaineers s Books softcover ISBN 0898867304 External links Edit Wikimedia Commons has media related to wbr Toroweap Formation wbr Toroweap Formation slopes wbr Toroweap Formation bedding wbr Toroweap Point and wbr Toroweap Overlook Retrieved from https en wikipedia org w index php title Toroweap Formation amp oldid 1064876556, wikipedia, wiki, book, books, library,
