Canyonlands National Park: Difference between revisions
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A warm shallow sea again flooded the region near the end of the Pennsylvanian. [[Fossil]]-rich [[limestone]]s, [[sandstone]]s, and [[shale]]s of the gray-colored Honaker Trail Formation resulted. A period of [[erosion]] then ensued, creating a break in the geologic record called an [[unconformity]]. Early in the [[Permian]] an advancing sea laid down the [[Halgaito Shale]]. Coastal lowlands later returned to the area, forming the [[Elephant Canyon Formation]]. |
A warm shallow sea again flooded the region near the end of the Pennsylvanian. [[Fossil]]-rich [[limestone]]s, [[sandstone]]s, and [[shale]]s of the gray-colored Honaker Trail Formation resulted. A period of [[erosion]] then ensued, creating a break in the geologic record called an [[unconformity]]. Early in the [[Permian]] an advancing sea laid down the [[Halgaito Shale]]. Coastal lowlands later returned to the area, forming the [[Elephant Canyon Formation]]. |
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[[Image:Canyonlands National Park88.jpg|thumb|right|Canyonland]] |
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Large [[alluvial fan]]s filled the basin where it met the [[Uncompahgre Mountains]], creating the [[Cutler Formation|Cutler red beds]] of [[iron]]-rich arkose sandstone. Underwater [[sand bar]]s and [[sand dune]]s on the coast inter-fingered with the red beds and later became the white-colored cliff-forming Cedar Mesa Sandstone. Brightly-colored [[oxidation|oxidized]] muds were then deposited, forming the Organ Rock Shale. Coastal sand dunes and marine sand bars once again became dominate, creating the White Rim Sandstone. |
Large [[alluvial fan]]s filled the basin where it met the [[Uncompahgre Mountains]], creating the [[Cutler Formation|Cutler red beds]] of [[iron]]-rich arkose sandstone. Underwater [[sand bar]]s and [[sand dune]]s on the coast inter-fingered with the red beds and later became the white-colored cliff-forming Cedar Mesa Sandstone. Brightly-colored [[oxidation|oxidized]] muds were then deposited, forming the Organ Rock Shale. Coastal sand dunes and marine sand bars once again became dominate, creating the White Rim Sandstone. |
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Increasingly dry climates dominated the Triassic. Therefore, sand in the form of sand dunes invaded and became the [[Wingate Sandstone]]. For a time climatic conditions became wetter and streams cut channels through the sand dunes, forming the Kayenta Formation. Arid conditions returned to the region with a vengeance; A large [[desert]] spread over much of western [[North America]] and later became the Navajo Sandstone. A fourth unconformity was created by a period of erosion. |
Increasingly dry climates dominated the Triassic. Therefore, sand in the form of sand dunes invaded and became the [[Wingate Sandstone]]. For a time climatic conditions became wetter and streams cut channels through the sand dunes, forming the Kayenta Formation. Arid conditions returned to the region with a vengeance; A large [[desert]] spread over much of western [[North America]] and later became the Navajo Sandstone. A fourth unconformity was created by a period of erosion. |
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[[Image:Canyonlands_Needles.jpg|thumb|right|Rock formations in the Needles district]] |
[[Image:Canyonlands_Needles.jpg|thumb|right|Rock formations in the Needles district]] |
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Revision as of 11:17, 4 October 2006
| Canyonlands National Park | |
|---|---|
| Location | Utah, USA |
| Nearest city | Moab, Utah |
| Area | 337,597.83 acres (337,570.43 federal) 1,366.21 km² |
| Established | September 12, 1964 |
| Visitors | 393,381 (in 2005) |
| Governing body | National Park Service |
Canyonlands National Park, located near Moab, Utah and the Arches National Park, was designated as a National Park on September 12, 1964. The park covers 527.5 mi² (1,366 km²).
Canyons carved into the Colorado Plateau by the Colorado River and Green River partition the area into three major districts:
- Island in the Sky to the north
- The Needles to the south-east
- The Maze to the west
Apart from the three major districts there is also a small detached section to the west, the Horseshoe Canyon.
Geography
The Island in the Sky and Needles districts are accessible via paved roads from U.S. 191 which passes through Moab. The Maze is the most remote of the three districts and is only accessible from the west (Utah 24 or 95) via unpaved roads. There are no road connections between the districts within the park and traveling between them may take two to six hours by car.
Island in the Sky is a broad and level mesa to the north of the park between Colorado and Green river with many spectacular overlooks over the White Rim, a sandstone bench 1200 feet (365 m) below the Island, and the rivers which are another 1000 feet (304 m) below the White Rim.
The Needles district is named after the red and white banded rock pinnacles which dominate it but various other forms of naturally sculptured rock like canyons, grabens, potholes, and a number of arches similar to the ones of the nearby Arches National Park can be found as well. Unlike Arches National Park, however, where many arches are accessible by short to moderate hikes or even by car, most of the arches in the Needles district lie in backcountry canyons and take long hikes or four-wheel-drive trips to reach.
This area was once home of the Ancestral Puebloan Indians of which many traces can be found. Although the items and tools they used have been largely taken away by looters, many of their stone and mud dwellings are well-preserved. The Ancestral Puebloans also left traces in the form of petroglyphs, most notably on the so-called Newspaper Rock near the Visitor Center at the entrance of this district.
The Maze district west of the Colorado and Green rivers is the most remote and inaccessible section.
The small detached section to the west, the Horseshoe Canyon unit, contains large panels of rock art made by hunter-gatherers who predated the Ancestral Puebloans. The most notable panel in the canyon is named the Great Gallery.
Geology
- Main article: Geology of the Canyonlands area
A subsiding basin and nearby uplifting mountain range (the Uncompahgre) existed in the area in Pennsylvanian time. Seawater trapped in the subsiding basin created thick evaporite deposits by Mid Pennsylvanian. This, along with eroded material from the nearby mountain range, become the Paradox Formation, itself a part of the Hermosa Group. Paradox salt beds started to flow later in the Pennsylvanian and probably continued to move until the end of the Jurassic. Some scientists believe Upheaval Dome was created from Paradox salt bed movement, creating a salt dome, but more modern studies show that the meteorite theory is more likely to be correct.
A warm shallow sea again flooded the region near the end of the Pennsylvanian. Fossil-rich limestones, sandstones, and shales of the gray-colored Honaker Trail Formation resulted. A period of erosion then ensued, creating a break in the geologic record called an unconformity. Early in the Permian an advancing sea laid down the Halgaito Shale. Coastal lowlands later returned to the area, forming the Elephant Canyon Formation.
Large alluvial fans filled the basin where it met the Uncompahgre Mountains, creating the Cutler red beds of iron-rich arkose sandstone. Underwater sand bars and sand dunes on the coast inter-fingered with the red beds and later became the white-colored cliff-forming Cedar Mesa Sandstone. Brightly-colored oxidized muds were then deposited, forming the Organ Rock Shale. Coastal sand dunes and marine sand bars once again became dominate, creating the White Rim Sandstone.
A second unconformity was created after the Permian sea retreated. Flood plains on an expansive lowland covered the eroded surface and mud built up in tidal flats, creating the Moenkopi Formation. Erosion returned, forming a third unconformity. The Chinle Formation was then laid down on top of this eroded surface.
Increasingly dry climates dominated the Triassic. Therefore, sand in the form of sand dunes invaded and became the Wingate Sandstone. For a time climatic conditions became wetter and streams cut channels through the sand dunes, forming the Kayenta Formation. Arid conditions returned to the region with a vengeance; A large desert spread over much of western North America and later became the Navajo Sandstone. A fourth unconformity was created by a period of erosion.
Mud flats returned, forming the Carmel Formation and the Entrada Sandstone was laid down next. A long period of erosion stripped away most of the San Rafael Group in the area along with any formations that may have been laid down in the Cretaceous period.
The Laramide orogeny started to uplift the Rocky Mountains 70 million years ago and with it the Canyonlands region. Erosion intensified and when the Colorado River Canyon reached the salt beds of the Paradox Formation the overlying strata extended toward the river canyon, forming features such as The Grabens. Increased precipitation during the ice ages of the Pleistocene quickened the rate of canyon excavation along with other erosion. Similar types of erosion are ongoing, but occur at a slower rate.
References
- Canyonlands National Park Service website
- Geology of National Parks: Fifth Edition, Ann G. Harris, Esther Tuttle, Sherwood D., Tuttle (Iowa, Kendall/Hunt Publishing; 1997) ISBN 0-7872-5353-7
- The National Parks: Index 2001–2003. Washington: U.S. Department of the Interior.
External links
- National Park Service: Canyonlands National Park
- Canyonlands Field Institute nonprofit support group
- Moab Travel Council Local travel and park services
- Canyonlands Natural History Association a not-for-profit organization established to assist the scientific and educational efforts of the National Park Service
- Canyonlands Half Marathon Annual May Race Festival
- Description and Photos of Horseshoe Canyon: Wilderness Utah
- Description and Photos of the Needles District: Wilderness Utah
