Surprise canyon formation
The Surprise Canyon Formation is a geological formation of conglomerates , sandstones , limestones and dark purple siltstone , which often occurs as "channel fill".
Emergence
The rocks are believed to have originated in the Mississippian and early Pennsylvania ages . They were deposited on a predominantly horizontally deposited, heavily eroded Redwall Limestone , originally formed as a marine deposit and reaching a thickness of 120 to 200 m (400-700 ft); When the Surprise Canyon Formation was formed, the Redwall Limestone was exposed to karstification in a "warm and humid" climate. The karstification created sinkholes , caves and underground channels as well as deep gorges and river valleys that arose from collapsing caves. Some valleys were apparently filled with clayey reddish-orange material, as it is known today from the tropics. Deposits of the Surprise Canyon Formation formed under the surface of the Redwall layers in the karst systems, and layers of the Redwall Limestone can now be found over the younger layers of the Surprise Canyon.
Occurrence
The Surprise Canyon Formation is found primarily in the areas around Grand Canyon Village , South Rim , and northwest, north, and northeast of it in Arizona . The formation is not continuous, but is found in separate geological sequences under the South Rim and its various landforms, and specifically on the landforms and cliffs of the Inner Gorge and the layers of the Redwall Limestone on the surface. Outstanding examples near Grand Canyon Village are Pattie Butte- ( Newton Butte ), Tower of Set, (west of Isis Temple ) and Brahma Temple's southern Redwall Limestone areas, and Johnson and Sturdevant Points, east of Isis Temple.
In the layers of the formation there are fossils of plant material, marine shells, and numerous fossils that come from the Redwall Limestone as "derived fossils". In addition, there are fossil terrain structures such as valleys and canyons that show the erosion of prehistoric times.
In addition to the easy-to-find structures on the Redwall Limestone surfaces, the layers of the Surprise Canyon Formation are also found in vertical layers, where the lowest layers of the Supai Group , the Watahomigi Formation (major sub-unit 1 of 4), pass into the layers of the Surprise Canyon, or rest on the Redwall Limestone. As stated earlier, the Surprise Canyon strata are discontinuous in the Grand Canyon Village region, but are found in all areas. This arrangement is explained by the fact that they were deposited when the surface of the Redwall Limestone was deeply furrowed by erosion, creating numerous channels in which the eroded material was deposited. A later hypothesis states that an estuarine region was formed in a coastal area in the west of the Proto-North American continent , in which the deposits of continental erosion accumulated. The uniformly thick layers of the Surprise Canyon Formation emerged in the canals, which are in stark contrast to the highly variable layer thicknesses that formed under conditions at sea level, and the thin, discontinuous accumulations, or thin lenses, which can be very pronounced regionally, which arose in the area of the estuaries (tidal zones).
The layers of Redwall Limestone, on the other hand, are massive and very evenly layered. They form the basic geological unit for most of the Grand Canyon and also form the walls of Marble Canyon to the northeast, where the Colorado River enters, about 30 mi (45 km) northeast of the Grand Canyon Village region, South Rim.
Surprise Canyon and Temple Butte Formation
In the center of the Grand Canyon , the Surprise Canyon and Temple Butte formations reach roughly the same thickness of 23–46 m (75–150 ft). The main difference between the two formations is that the Devonian Age Temple Butte Formation was deposited in the western Grand Canyon region, as well as regions of Nevada , on the edge of the proto-North American continent; the continental shelf sank, creating sedimentary basins , and the Temple Butte Formation reached a thickness of 122 m (400 ft) in places, for example in the west of the Grand Canyon at the Grand Wash Cliffs , and even thicknesses up to 610 m ( 2000 ft) in the Frenchman Mountain region of Nevada.
Both the Temple Butte and Surprise Canyon Formations were deposited in erosion-formed discordances in karst areas on layers of the Muav and Redwall limestone.
The following table juxtaposes the Surprise Canyon Formation, Redwall Limestone, Temple Butte Formation, and other related geological units of the Colorado Plateau :
| Grand Canyon and central northeast Arizona | East and Southeast Utah | Uncompahgre plateau | NE Utah NW Colorado (proto) - Uintah Basin |
time |
|---|---|---|---|---|
|
Ancestral Rocky Mountains (eroded at sea level) |
approx. 165 million years | |||
| Supai Group | Hermosa Group | Ancestral Rocky Mtns | Hermosa Group | about 340- (330) -285 Ma |
|
Watahomigi Formation Unit 1 of 4 of the Supai Group, Upper Pennsylvania -Lower Permian |
(Hermosa) | Ancestral Rocky Mtns | Hermosa members? | approx. 1-316 Ma |
| Surprise Canyon Formation- ( Grand Canyon only ) |
Ancestral Rocky Mtns | 325-316 Ma | ||
| Discordance | Ancestral Rocky Mtns | 5 Ma | ||
|
Mississippinum Redwall Limestone |
Leadville Limestone | Ancestral Rocky Mtns | Leadville Limestone | 365-330 Ma |
|
Devon Temple-Butte-Formation 120 m thick in the west of the Grand Canyon , (Greater thickness in Nevada) ( Verde Valley , AZ, ~ 100-mi southeast of the Grand Canyon: Martin Formation ) |
Elbert formation ? | Ancestral Rocky Mtns | 410-365 Ma | |
| Erosion discordance ( Ordovician -65 Ma, Silurian 25 Ma, no deposits) |
Ancestral Rocky Mtns | 50 Ma | ||
| 3 Muav Limestone 2 Bright Angel Shale (~ 520 Ma) -1- Tapeats Sandstone |
3? - Lynch Dolomite 2- Bright Angel Shale 1? - Sawatch Sandstone |
Ancestral Rocky Mtns | 505 Ma 515 Ma 525 (544) Ma |
Individual evidence
- ↑ Geologic Map of the Grand Canyon in the Vicinity of the South Rim Visitor Center, based on: Geologic map of the eastern part of the Grand Canyon National Park, Arizona, PW Huntoon and others, (c. 1995, Grand Canyon Association), (from Geologic Highway Map of Arizona , from Reynolds, c. 1988).
- ^ South Rim (geologic) Visitor Center Map , Stratigraphy Chart.
- ^ South Rim (geologic) Visitor Center Map , Stratigraphy Chart.
- ^ "Warm, and humid" Chronic 1983. Roadside Geology of Arizona, c. 1983, Grand Canyon National Park : 279-287, 283.
- ↑ sinks, caves, and underground channels, and created deep ravines and stream valleys developed as caverns collapsed. Chronic, 1983: 283.
- ↑ 'clayey red-orange soil' similar to that known in the tropics today. Chronic, 1983: 283.
- ^ Arizona Road & Recreation Atlas, Benchmark Maps, 2nd Edition, c. 1998: 62-63.
- ^ Blakey, Ranney: Ancient Landscapes of the Colorado Plateau. 2008. Graphic: Columnar cross-sections of Paleozoic rocks showing the stratigraphic nomenclature and correlations used in this book. S. XVIII.
- ^ Blakey, Ranney, 2008. Ancient Landscapes of the Colorado Plateau , 165 Ma map: (upper) - Carmel-Formation , with Sundance Sea , pp. 76, 78.
- ^ Blakey, Ranney, 2008. Ancient Landscapes of the Colorado Plateau , Graphic: Columnar cross-sections of Paleozoic rocks showing the stratigraphic nomenclature and correlations used in this book, pg. XVIII.
literature
- Arizona Road & Recreation Atlas, Benchmark Maps, 2nd Ed., C. 1998: 28-29, 62-63.
- Ron Blakey, Wayne Ranney: Ancient Landscapes of the Colorado Plateau. Grand Canyon Association (54 (23 pairs), 46 maps specific to the Colorado Plateau ) 2008. ISBN 978-1-934656-03-7 .
- Chronic: Roadside Geology of Arizona, c. 1983, 23rd Ed., Mountain Press Publishing Co. Grand Canyon National Park 1983: 279-287 [283]. ISBN 978-0-87842-147-3 .
- Arizona DeLorme Atlas & Gazetteer, 5th Edition, c. 2002: 23, 24, 31, 32.
- Arizona Road & Recreation Atlas, Benchmark Maps c. 1998: 28-29, 62-63.
- Halka Chronic: Roadside Geology of Arizona, c. 1983 Mountain Press Publishing Co .: 229-232 ( US 89A Marble Canyon-Fredonia ): 179-180. ISBN 978-0-87842-147-3 .
- Ivo Lucchitta: Hiking Arizona's Geology. Mountaineers's Books 2001. ISBN 0-89886-730-4 .
