Goat Rocks

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Goat Rocks
The Goat Rocks with Gilbert Peak at the top left

The Goat Rocks with Gilbert Peak at the top left

height 2500  m
location Lewis County / Yakima County , Washington , USA
Mountains Cascade chain
Coordinates 46 ° 29 ′ 19 ″  N , 121 ° 24 ′ 21 ″  W Coordinates: 46 ° 29 ′ 19 ″  N , 121 ° 24 ′ 21 ″  W
Goat Rocks (Washington)
Goat Rocks
Age of the rock 3.2 Ma - ~ 500,000 BP
First ascent Fred G. Plummer, 1899
Normal way Climb

The Goat Rocks are an extinct stratovolcano in the cascade chain between Mount Rainier and Mount Adams in the south of the US state Washington , which was last active in the Pleistocene . As one of the Cascade Volcanoes , it was formed by subduction of the Juan de Fuca Plate under the western edge of the North American Plate . The volcano was about 3.2 million years ago to between one and a half million years before present active . Throughout its complex eruptive phase, the siliceous explosive eruptions changed into voluminous mafic activity.

The volcano and the surrounding Goat Rocks Wilderness (designated in 1964) are named after the numerous mountain goats that live in the area. The variable climate of the wilderness area offers a habitat for various animals, including marmots, whistles, deer and elk. Various peaks of the wilderness area can be climbed by climbing tours . Hiking in the area is allowed. The area is full of minerals and raw materials, including coal, cobalt , copper, and base metals .

Geography and geology

The Old Snowy Mountain in the Goat Rocks Wilderness of the north with the snow-capped glaciers McCall and Packwood flanking the summit
The Goat Ridge with a view of the Mount Adams massif

The Goats Rocks volcano is located in the south of Washington, about 113 km west of Yakima , at about 46.5 ° N and 121.45 ° W. This region of the Cascade Range was originally settled by Indians who hunted and fished in the vicinity of the volcano and used the paths as trade routes. The Goat Rocks are located in a zone of periodic volcanism, which produced many small volcanic vents, including the volcanic fields at Mount Adams and Indian Heaven . Located in the eastern part of the Cascade Range , the Goat Rocks are located in the extreme northwest of the catchment area of ​​the Klickitat River . As one of the cascading volcanoes , the Goat Rocks were formed by subduction of the oceanic Juan de Fuca plate under the western part of the continental North American plate . This fault, called the Cascadia subduction zone , lacks the deep-sea channel that can usually be found at converging plate boundaries, which can possibly be explained by the slow rate of subduction. According to the United States Geological Survey , the Nazca and North American plates are converging at a rate of 3 to 4 centimeters per year, only half of their convergence rate from seven million years ago.

Washington's Cascade Volcanoes are limited to four zones; the Goat Rocks form a segment of the Mount Adams Belt, moving north to south, which also includes the Tumac Mountain, Mount Adams and King Mountain Fracture Zones. Of the four zones, this contains the second most volcanoes, which are dominated by calcareous-alkaline to tholeitic to basaltic andesites . The Goats Rocks and their immediate surroundings are characterized by pre- tertiary Grauwacken and Argillites . These deposits are traversed by various emerging northward expanding faults . These deposits are overlaid by Cenozoic volcanic rocks, which include the thick Eocene Ohanapecosh Formation, which is composed of chemically altered basalts and andesites, as well as andesite banks and Dacite pyroclastic sediments . In contrast, the overlying Ohanapecosh layer consists of quartz- containing siliceous tuff , rhyolite and other pyroclastic rocks. Underneath both layers is the Russell Ranch Formation, some 2,300… 3,000 meters thick, which contains deposits of lapilli and tuff that suggest a caldera , although geologists have not found clear evidence of such a caldera in this zone.

Together with Mount Adams, Mount Rainier and Mount St. Helens , the Goat Rocks form a volcanic triangle, an arrangement that cannot be found anywhere else in the cascades. This could be related to a zone in the central crust of the earth that has abnormally high electrical conductivity . This zone is the Southern Washington Cascades Conductor (SWCC), which is not really understood by geologists. In 1994, scientists from the United States Geodynamics Committee hypothesized that this anomaly was related to a large deposit of sedimentary rocks advancing against a continental margin . Hill et al. rejected this view in 2009 because it has been proven to be inconsistent with the macrotelluric maps of the area. Instead, they suggest that the anomaly is related to volcanism in the region, which is due to partial melting of the earth's crust.

The Goat Rocks are the oldest stratovolcano of the Cascade Range, which was formed after the Columbia River Basalt Group and in terms of volume with about 60 cubic kilometers is roughly comparable to Mount St. Helens or smaller than Mount Baker. Rough estimates give 40% tuff and breccia for the composition of the rocks . The remnants of their lava flows can be found in the valleys of the Tieton , Klickitat and Cispus River , the depth of which resembles a relief reversal of mountain ridges due to erosion . These rivers are completely eroded, but testify to the former size of the volcano.

outbreaks

The Goat Rocks Volcano as seen from Mount Adams

The Goat Rocks are a stratovolcano with a somewhat complicated history of eruptions. They first became active about 3.2 million years ago during the Pliocene . The outbreaks were initially explosive and hurled silizische lava with highly felsic rocks such as rhyolite to the surface. One of these events produced deposits of tuff approximately 650 m high that remained on the eastern flank of the mountain. Three million years ago the Goat Rocks changed into a mafic volcano that ejected olivine and basalt. When the eruptions are continued until the Pleistocene lava flows were increasingly andesitic and contained mainly pyroxene with phenocrysts as well hornblende -Mineralen. These Andesitic lava flows formed the main building of the volcano about 2.5 to 0.5 million years ago, which may have resembled today's Mount Rainier. At that time, the Goat Rocks eruptions were very voluminous; the lava spread far from the volcano, with satellite vents possibly contributing. It is estimated that a million years ago the Goat Rocks created an andesitic lava flow that flowed about 80 km down the Naches and Tieton Rivers valleys and is believed to be the longest andesitic lava flow on earth. Much of this flow has since been interrupted around the volcano by plutonic dykes , which form a radial arrangement around the core of the volcano. When the erosion set in on a large scale, the volcano remained active and produced more andesitic lava flows with hornblende. The eruptive activity continued on Old Snowy Mountain into the middle to late Pleistocene and also produced andesitic lava flows with hornblende, which were ultimately shifted by glaciers into the valley of the Cispus River; Whether the Old Snowy Mountain is a vent of the Goat Rocks or an independent volcano remains unclear. Hornblende andesites can also be found at the highest point of the Goat Rocks Wilderness, Gilbert Peak.

Hogback Mountain, a shield volcano north of the Goat Rocks and south of White Pass , was discovered by Siebert et al. (2010) identified the Goat Rocks as a satellite vent. At a height of 700 meters it hurled more than 200 m thick layers of olivine basalts and basaltic andesites from the end of the Pliocene to the early Pleistocene. The eruptions of the Goat Rocks formed an extensive, approx. 30 km × 15 km large volcanic field , which is characterized by small lava domes in the north.

icing

Although it may once have been a towering stratovolcano, the Goat Rocks have been subject to intense erosion since they cooled down. When the eruptions stopped one day, the glaciers and the hydrothermal metasomatosis of the volcanic interior had pushed away the layers of volcanic ash and lava deposits, exposing the rocky vertical lava monoliths ("lava spines") where the magma in the volcanic channels cooled and so on got hard. Almost all of the remaining volcanic debris was partially covered by younger rock.

The Goat Rocks area is remarkably intensely glaciated despite its moderate altitude and southern exposure (compared to the rest of the cascades). Four major glaciers cover the north and northeast slopes of the peaks: the Conrad Glacier , McCall Glacier , Meade Glacier, and Packwood Glacier ; there are also numerous smaller permanent snow fields.

Panorama from Goat Ridge with Old Snowy Mountain (left under clouds)

Main peaks around Goat Rocks

The Goat Rocks volcano and its surroundings range from 914 to 2500 meters at its highest point, Gilbert Peak . Because of the intense glaciation and erosion, most of the peaks around the Goat Rocks are rather moderately high.

f1Georeferencing Map with all coordinates of the main peaks section around Goat Rocks : OSM

summit height Coordinates source
Gilbert Peak (Mount Curtis Gilbert) 2,494 m 46 ° 29 ′  N , 121 ° 25 ′  W. Gilbert Peak, Washington . Retrieved June 21, 2018.
Big horn 2,438 m 46 ° 30 ′  N , 121 ° 25 ′  W. Big Horn, Washington . Retrieved June 21, 2018.
Old Snowy Mountain 2,402 m 46 ° 31 '  N , 121 ° 27'  W. Old Snowy Mountain, Washington . Retrieved June 21, 2018.
Goat Ridge 2,068 m 46 ° 31 '  N , 121 ° 30'  W Goat Ridge, Washington . Retrieved June 21, 2018.
Hawkeye Point 2,265 m 46 ° 31 '  N , 121 ° 30'  W Hawkeye Point, Washington . Retrieved June 21, 2018.
Ives Peak 2,414 m 46 ° 30 ′  N , 121 ° 27 ′  W. Ives Peak, Washington . Retrieved June 21, 2018.
Tieton Peak 2,369 m 46 ° 31 '  N , 121 ° 24'  W. Tieton Peak, Washington . Retrieved June 21, 2018.
Devils Horn 2,146 m 46 ° 31 '  N , 121 ° 22'  W. Devils Horn, Washington . Retrieved June 21, 2018.
Johnson Peak 2,282 m 46 ° 32 ′  N , 121 ° 30 ′  W. Johnson Peak, Washington . Retrieved June 21, 2018.
Bear Creek Mountain 2,236 m 46 ° 32 '  N , 121 ° 21'  W. Bear Creek Mountain, Washington . Retrieved June 21, 2018.
Chimney skirt 2,033 m 46 ° 34 ′  N , 121 ° 29 ′  W. Chimney Rock ( English ) In: Geographic Names Information System . United States Geological Survey . Retrieved June 21, 2018.
Hogback Mountain 2,071 m 46 ° 36 '  N , 121 ° 24'  W. Hogback Mountain, Washington . Retrieved June 21, 2018.

Wilderness area

A herd of mountain goats as seen from the Pacific Crest Trail

The land surrounding the Goat Rocks was first protected by the United States Department of Agriculture in February 1931 when an estimated 18,000 hectares were placed under provisional protection. This area was expanded to 29,315 hectares in 1935 and again to 33,459 hectares in 1940. In 1964, Congress created the Goats Rock Wilderness as part of the National Wilderness Preservation System and handed management over to the United States Forest Service . Since 1984 some areas were added, it now covers 43,745 hectares between Mount Rainier and Mount Adams and extends over the Gifford Pinchot National Forest and the Okanogan - Wenatchee National Forest . It is bounded in the southeast by the Yakama Indian Reservation.

The wilderness area varies in height between 914 and 2,500 meters. It offers alpine tundras (mats) with glaciers, small lakes and ponds as well as 15 different hiking routes with a total length of 193 kilometers. One of these trails forms the highest section of Washington's famous Pacific Crest Trail , which runs 50 km from north to south through the center of the wilderness area. Because this route is at such altitude, hikers can be exposed to violent storms that can be dangerous for unprepared groups. Much of the wilderness area lies above the tree line and offers views of the alpine landscape.

Climate, flora and fauna

The weather in the wilderness area varies greatly as the mountains act as a barrier to clouds and heat. The cascade chain forms a barrier to moisture-transporting storms and forces the air masses to rise and thus cool down. This cooled air cannot absorb as much moisture as the warmer air, so that heavy rainfall (up to 3,810 mm annually) occurs on the western flanks of the mountains, which led to dense forest cover. The snowfalls typically amount to more than 8 m annually, so that the snow masses are still partially present in July or August. In the warmer months, the meltwater flows into lakes and keeps them always full. Because the mountains are so high, the storm clouds can get stuck even if the storm continues itself, which can lead to blizzards and frosts year-round. Under extreme conditions, these storm cells put hikers at risk from high wind speeds, fog, snow, and rain, which can potentially make hiking impossible. On the east side of the mountains, the air warms up again on the descent and creates down winds , comparatively little rainfall and, as a result, less forested landscapes. Due to these conditions, the temperatures on the west side of the mountains are stable, whereas the temperatures on the east side vary greatly.

The Goat Rocks got their name from a mountain goat population that can be seen around the mountain. Further elements of the fauna of the high areas are marmots and whistles . Deer and elk can be seen below the tree line, including mule deer (the black- tailed deer subspecies is common), Roosevelt elk ( Cervus canadensis roosevelti ), and Rocky Mountain elk ( Cervus canadensis nelsoni ), the latter from Yellowstone National Park in 1913 were introduced .

Climbing and recreation

Old Snowy Mountain and Gilbert Peak, two of the peaks in the Goat Rocks Wilderness, are frequented by hikers and climbers . Both are considered remote peaks, although Old Snowy Mountain is the more accessible of the two. This, together with the easier ascent, makes it a more popular climbing destination. There are several routes to the summit that take 5–6 hours and overcome 1,097 meters of altitude. The Old Snowy can be climbed on a 23 km long circular route or hiked over glaciers, even if a trail exists. From the summit, bidders can see Mount St. Helens and Mount Rainier in the distance. Because the area is covered extensively with loose mountain debris and rocks, there is a risk of avalanches.

The first ascent of Gilbert Peak took place in 1899 by Fred G. Plummer. The ascent also comprises 1,097 vertical meters and requires 6–8 hours for the ascent itself and the time for the 26 km long circular route. Because the routes are longer and technically more demanding because of the loose scree, the ascent of Gilbert is more difficult than that of Old Snowy Mountain. Most climbers tend to climb Gilbert Peak early in the climbing season when the snow cover is thin.

Recreational activities allowed by the Forest Service include day hikes, horseback riding, and long distance hiking . Because the Goat Rocks are part of the National Wilderness Preservation System , motor vehicles and transportation are prohibited. This includes motorcycles, cars, motor boats and helicopters. A free permit is required to enter the wilderness area.

raw materials

In terms of mineral resources, the Goat Rocks area can be divided into three segments, each of which contains different minerals. The first two are called Packwood Glacier - McCall Basin (Eng. "Packwood Glacier - McCall Basin") and Glacier Basin (Eng. "Glacier Basin") and are located near the former volcanic vents. These areas show abnormal levels of cobalt , copper , lead , molybdenum , nickel and zinc , finely divided pyrite and localized concentrations of silver . The third area is related to the Clear Fork Cowlitz River and lies along the contact zone between the Goat Rocks volcano and the older volcanoes to the east. It is separate from the other two areas and shows abnormal levels of barium , cobalt, copper and manganese , as well as lower levels of lead, molybdenum, nickel and zinc. Other minerals found in the third area are barite , boron , cinnabar , elemental mercury , pyrite and tin , which come from the river sediment. The water contains high concentrations of chlorine , copper, fluorine and molybdenum. The rocks modified by metasomatosis contain arsenic , lead, manganese, molybdenum and zinc in extremely high concentrations. The area around the Goat Rocks appears to contain large deposits of base metals . Outside the investigated area, coal was found on the glacier fields of Packwood and Cowlitz; Building materials such as stones and gravel are broken in the north and west of the volcano . The potential oil and gas reserves of the Goat Rocks area remain undiscovered. Because no volcanic activity was observed during the Holocene (within the last 11,700 years), the Goat Rocks have very little potential for the use of geothermal energy .

Claims for three- gang mines and a single coal mine exist in the Goat Rocks Wilderness, but the United States Bureau of Mines (comparable to the German mining offices ) has no reports of funding on the claims. Historically, two claims have been staked in the area: 1934 the Mosquito Dike near Walupt Lake and 1939 the Glacier Dike near the Packwood Glacier. Neither shows any signs of development and both deposits are now abandoned. Miners may be drawn to news of gold , silver and copper discoveries along the breccia and shear zone to the north of the wilderness area.

See also

Commons : Goat Rocks Wilderness  - album with pictures
Commons : Cascade Volcanoes  - Album with Pictures

Individual evidence

  1. a b c d e f g Wilderness: Goat Rocks - Gifford Pinchot . United States Forest Service . 2015. Retrieved May 18, 2015.
  2. a b c d e f Smith, James G .: Geological Map of Upper Eocene to Holocene Volcanic and Related Rocks in the Cascade Range, Washington . United States Geological Survey . 1993.
  3. a b c d e f g h Wood, Charles A. and Jürgen Kienle (eds.): Volcanoes of North America: United States and Canada . Cambridge University Press, Cambridge, England 1992, ISBN 978-0-521-43811-7 .
  4. a b c d e f Barstad, Fred: Hiking Washington's Goat Rocks Country: A Guide to the Goat Rocks and Lewis and Cispus River Regions of Washington's Southern Cascades . Globe Pequot Press, 2004.
  5. ^ Topinka, Lyn: Description: Volcanic Fields and Centers near Mount Adams, Washington . United States Geological Survey . February 27, 2002. Retrieved April 24, 2010.
  6. The Volcanoes of Lewis and Clark, April 15, 1806 . United States Geological Survey . July 2004. Retrieved May 19, 2015.
  7. Geologic Provinces of the United States: Pacific - Cascades volcanic province . United States Geological Survey . October 2, 2014. Archived from the original on September 6, 2015. Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved May 30, 2015. @1@ 2Template: Webachiv / IABot / geomaps.wr.usgs.gov
  8. ^ A b Michael A. Korosec, William M. Phillips, J. Eric Schuster, ZF Danes, JH Biggane, PE Hammond, GA Clayton: The 1980–1982 Geothermal Resource Assessment Program in Washington: Open File Report 83-7 . Washington State Department of Natural Resources, August 1983.
  9. ^ A b c S. E. Church, TJ Close: Goat Rocks Wilderness and Adjacent Roadless Areas, Washington . United States Geological Survey , 1984.
  10. a b c d e f g p E. Church, DA Swanson, DL Williams, GA Clayton, TJ Close, TJ Peters: Mineral Resource Potential of Goat Rocks Wilderness and Adjacent Roadless Areas, Lewis and Yakima Counties, Washington . United States Geological Survey , 1983.
  11. Commission on Geosciences, Environment and Resources; US Geodynamics Committee; National Research Council, Division on Earth and Life Studies (Ed.): Mount Rainier: Active Cascade Volcano . National Academies Press, 1994, p. 39.
  12. ^ Graham J. Hill, T. Grant Caldwell, Wiebke Heise, Darren G. Chertkoff, Hugh M. Bibby, Matt K. Burgess, James P. Cull, Ray AF Cas: Distribution of melt beneath Mount St Helens and Mount Adams inferred from magnetotelluric data . In: Nature Publishing Group (Ed.): Nature Geoscience . 2, October 25, 2009, pp. 785-789. doi : 10.1038 / ngeo661 .
  13. a b c Stephen L. Harris: Fire Mountains of the West: The Cascade and Mono Lake Volcanoes (3rd ed.) . Mountain Press Publishing Company, 2005, ISBN 0-87842-511-X .
  14. Lee Siebert, Tom Simkin, Paul Kimberly: Volcanoes of the World . University of California Press , 2010, p. 408.
  15. a b c d e f Fred Beckey : Columbia River to Stevens Pass . The Mountaineers Books, 2000, ISBN 978-0-89886-577-6 .
  16. a b c d Gifford Pinchot National Forest: Goat Rocks Wilderness . United States Forest Service . 2015. Retrieved May 20, 2015.
  17. a b Goat Rocks Wilderness: General . In: Wilderness.net . United States Forest Service and the University of Montana . Retrieved May 20, 2015.
  18. a b c d Jeff Smoot: Climbing Washington's Mountains: Summit Hikes, Scrambles and Climbs in Washington's Cascade and Olympic Mountain Range . Globe Pequot Press, 2002.
  19. Gifford-Pinchot National Forest Wilderness Regulations . United States Forest Service . 2015. Retrieved May 20, 2015.
  20. ^ Goat Rocks Wilderness: Area Management . In: Wilderness.net . United States Forest Service and the University of Montana . Retrieved February 20, 2015.