Silver Star Mountain (Skamania County, Washington)

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Silver Star Mountain
The summit of Silver Star Mountain with Mount St. Helens in the background

The summit of Silver Star Mountain with Mount St. Helens in the background

height 1330  m (North American Vertical Date of 1988)
location Skamania County , Washington , USA
Mountains Cascade chain
Coordinates 45 ° 44 ′ 51 ″  N , 122 ° 14 ′ 20 ″  W Coordinates: 45 ° 44 ′ 51 ″  N , 122 ° 14 ′ 20 ″  W
Topo map USGS Bobs Mountain
Silver Star Mountain (Skamania County, Washington) (Washington)
Silver Star Mountain (Skamania County, Washington)
Template: Infobox Berg / Maintenance / TOPO-MAP

The Silver Star Mountain is an extinct volcano in the Cascade Range in the State of Washington ; it is part of the Cascade Volcanic Arc . The mountain consists of late Eocene to Oligocene rocks. It lies within the Gifford Pinchot National Forest . After a long period of inactivity, the volcano lies over three lithological units (individual rock layers, each of which has different physical properties), including the Silver Star Granodiorite unit.

The summit can be hiked and is well known by local mountaineers.

geography

Silver Star Mountain is located in Skamania County in the US state of Washington . In terms of the 1988 North American Vertical Date, it reaches an elevation of 4,364 ft (1,330 m), but the Geographic Names Information System database records 4,377 ft (1,334 m) as its altitude, and The Columbian , a newspaper from Vancouver, Washington ) , indicates 4,382 ft (1,336 m) as the height. The volcano lies in the western section of the middle cascade range . It is located approximately 12 mi (19 km) north of the western edge of the Columbia River Gorge and is linked to the state highways of Washington from Portland, Oregon by United States Forest Service roads. The volcano is located in the southwest of the Gifford Pinchot National Forest , which covers an area of ​​1,300,000 acres (5,261 km²) in southwest Washington.

physical geography

The area around the Silver Star Mountain consists of an eroded plateau, which was largely formed from lava; the average relief height is about 2,000 ft (approx. 610 m) and reaches local maxima of 3,000 ft (914 m). Unlike the rest of the western hinterland of the Cascades, this area has a rocky ridge-shaped appearance, the silhouettes similar to those in the northern cascades. The area lacks trees; it contains steep cliffs, scree slopes and flowery meadows.

Drainage is via the Washougal River and the South Fork Lewis River , which flow south and west, respectively. The erosion by these rivers has divided the land and created a relief with elevations between 2,500 ft (approximately 760 m) and 3,000 ft (approximately 910 m). Rainfall peaks during the winters and usually falls as snow that is blown away , particularly in the area's deep canyons. Some of these drifts persist until summer and feed small streams in the area. The surface runoff has increased due to the burning of the forests; so there were devastating forest fires in 1902 and 1929. This surface runoff has created gullies in the slopes and contributed to the erosion of the topsoil. Furthermore, there are rubble heaps with heights of up to 1,200 ft (approx. 370 m), which cover large parts of the granodiorite deposits. Small cirque-like basins, likely created by smaller glaciers , occur in some of the larger canyons and reach depths of up to 75 ft (23 m). Many of these cirques are filled with lakes, some encourage snow drifts.

The ground on and around the mountain was eroded by several forest fires, in particular the Yacolt fire of 1902 and 16 other fires in 1929. The slow recovery of the vegetation motivated the Civilian Conservation Corps to plant more trees in the 1930s and in the 1960s Years to create terraces to allow better vegetation regeneration.

ecology

Wildflowers grow at unusually low altitudes on Silver Star Mountain as a result of forest fires, wind, and rocky subsoil . There are more than 100 wildflower species and flowering shrubs on the volcano, including heather , Mormon tulips , tiger lilies , Grey's lovage , irises of the genus Dierama , bear grass , western meadow knotweed , columbines , avalanche tooth lily , broad-leaved lupine , woolly sunflower , Cardwell's beard thread , Indian brush , phlox , balsam roots and large-flowered dog's tooth . Hiking trails around the volcano also offer views of flower-covered slopes, paths through huckleberry thickets and through noble fir forests.

geology

In the area around Silver Star Mountain, the rocks form three lithological units (characterized by visible physical differences or the general appearance of the rock). The Eagle Creek rock formation is the oldest and likely dates from the Oligocene (or Lower Miocene ). The rock consists mostly of cream-colored vitric tuffs , which were exposed to weathering and thus turned into yellow or white-colored deposits, although there were also multi-colored tuffs that varied from red to green and purple breccias . Often the color depends on iron inclusions. They show little sorting and storage, which suggests that they were enriched at the surface of the earth. Rocks from this formation form outgrowths in the eastern part of Silver Star Mountain and emerge in the central part of the Columbia River Gorge. Further near-surface formations can be seen in the Silver, Bluebird and Bear Creek, where they occur in the canyons along the eastern part of the volcanic massif.

The second, younger unit is the Skamania andesites, which are found above the Eagle Creek deposits in thick andesite layers with smaller inclusions of breccias and pyroclastic material. They are less exposed than the Eagle Creek deposits and are often unevenly stored over the Eagle Creek rocks at depths of 5 ft (2 m) due to complete erosion. In other places, e.g. B. on the eastern boundary of the Silver Star area, they occur between the layers of Eagle Creek tuff, possibly due to overlapping deposition periods or a combination of tuff deposition and andesite extrusion . Of the three lithological formations, the Skamania andesites are the most widespread in the area, they formed thin layers that indicate that the lava was particularly fluid. Andesites deposited in higher elevations on the Silver Star Mountain Massif were subject to less erosion than those in lower elevations. The age of the Skamania andesites is unknown, although Felts (1939) hypothesized that they could have formed during the early Middle Miocene. They have a gray to green-gray color and are porphyritic with small inclusions of breccia and tuff and phenocrysts of plagioclase , Augiten and magnetite . The prisoners are between one and six millimeters in size, the average diameter is three millimeters. Every now and then they contain chlorite or similar minerals. Rocks from the upper third of the Skamania andesites have a similar composition, but are more vesicular in texture .

The third unit is called the Silver Star Granodiorite, which consists of Augites, Diorites and Quartz Diorites. Dykes with quartz, tourmaline, and sericites occur within the mass, which contain light-colored white to pink plagioclases with orthoclases , clear quartz, and black to green biotite and hornblende crystals. The unit is about 10 mi (16 km) long and between 1.5 mi (2 km) and 2.5 mi (4 km) wide and spreads along an axis shifted 20 degrees to the east. It has steep walls that have not yet been hollowed out by local canyons that have dug into the nearby rocks. Felts (1939) suggested that the material entered at an angle of 20 degrees east to north. The material intersects the Eagle Creek Formation and the lower two thirds of the Skamania andesites to form a metamorphic material and small dykes of granodiorite and aplite embedded in tuff and andesite deposits. The absence of dykes and intercalations in the upper third of the Skamania andesite suggests a time gap between the lower and upper segment deposits during which the granodiorite intrusion occurred. The granodiorite became scree, and there are few eruptions that can only be observed at the bottom of streams and rarely on cliffs that have not yet been covered by scree. Lava flows, possibly produced during the Pleistocene , poured into Lewis River Canyon (4 mi (6 km) west of Silver Star Mountain) and the Wind River Canyon to the east.

The Silver Star Mountain consists of rocks from the late Eocene and the Oligocene, partly made up of calcareous-alkaline volcanoclastic sediments. These rock formations were introduced on the east side of the mountain by the Silver Star Intrusion , a massive granodiorite and quartz diorite deposit that also created small copper deposits in the area. Calc-alkaline volcanoclastic sediments, known to have originated from the Skamania volcanoes, were deposited nearby and overlap with the Troutdale formation. During the Miocene, these deposits formed mounds north of the main Columbia River valley high enough to prevent flooding.

Silver Star Mountain is the center of a Plutonic magma that entered the area about 20 million years ago and cooled below the surface to form solid rock, forming smaller deposits of gold , zinc , copper, zeolites , quartz and calcite . Small abandoned gold mines can be found within the creek bottoms throughout the area. EA Dole, an early settler, struck silver on the mountain in 1874. He named his mine Silver Star Quartz Ledge. The ore recovered was valued at 41.17 silver and 63.72 lead per ton. Granite is documented near the base of the mountain on the Columbia River, approximately 15 mi (24 km) northeast of the city of Washougal . The volcano ejected a granodiorite dyke that was deposited nearby. Much of the local soils arose from granodiorite deposits and volcanic ash.

history

A number of trenches can be visited near Silver Star Mountain on one of the trails that have come to be known as the Indian Pits; the trail therefore takes its name and is referred to as Indian Pits Trail # 180E. Such trenches are found in other parts of the Columbia River Gorge area. Archaeologists discuss the purpose of these trenches, and three prominent hypotheses have been derived from them. One states that they were created by Indians in search of spiritual visions, while another interprets them as residences that helped hunters to ambush mountain sheep or goats, pumas and wolves who fled downhill from the scree slopes. The third hypothesis assigns them a storage function for food supplies.

In September 1902, the Yacolt fire started as a clearing fire near the town of Stevenson . Spreading by a strong easterly wind, it burned the forest for over 30 mi (48 km), reached the village of Yacolt, claiming 38 lives . The fire affected nearly 239,000 acres (967 km²) of land across southwest Washington, including portions of Clark , Cowlitz and Skamania Counties . Sixteen smaller fires occurred in the following decades, which prompted the authorities to erect a fire watch tower on the Silver Star, which was built in 1952 on the higher northern summit ("Star Lo"), but was removed in 1969. The Yacolt Burn State Forest was named after the 1902 fire.

tourism

The area at Silver Star Mountain is little used by hikers. The Silver Star Trail runs 5 mi (8 km) to an old road west of Silver Star Mountain, while the Silver Star Summit Trail # 180D, 0.25 mi (0.4 km) long, runs to the summit of Silver Star Mountain reached. The Indian Pits Trail # 180E and the Pyramid Rock Trail # 180F branch off the Silver Star Trail south of Silver Star Mountain. From Ed's Trail # 180A, named after Edward Robinson, one of the pioneers of the Chinook Trail Association, hikers can enjoy views of nearby volcanoes such as Mount Saint Helens , Mount Rainier , Mount Adams , Mount Hood, and Mount on clear days Enjoy Jefferson . This hike is described by local residents as one of the best in Washington, with only about 1,200 ft (366 m) of elevation gain between Silver Star and Ed's Trail. Trail # 172 Bluff Mountain offers views of the metropolitan areas of Vancouver and Portland.

The walking area is administered by the United States Forest Service. The Mount Adams Ranger District serves as an information center. A number of trails have been established and are maintained by the Chinook Trails Association.

Individual evidence

  1. ↑ a b c Silver Star Mountain LO . National Geodetic Survey. Retrieved July 9, 2018.
  2. ↑ a b Silver Star Mountain ( English ) In: Geographic Names Information System . United States Geological Survey . Retrieved July 20, 2018.
  3. ^ A b c d e f A. Thomas: Silver Star Mountain, Loowit Falls trails among forest highlights . In: The Columbian , Columbian Publishing Co., February 23, 2013. Retrieved August 14, 2018. 
  4. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab W. M. Felts: A Granodiorite Stock in the Cascade Mountains of South-western Washington . In: The Ohio Journal of Science . 39, No. 6, 1939, pp. 297-316.
  5. ↑ a b c Fire created the open hillsides of Silver Star . United States Forest Service . Retrieved August 14, 2018.
  6. ↑ a b c Trail # 172 Bluff Mountain . United States Forest Service . August 6, 2018. Retrieved August 14, 2018.
  7. ↑ a b Earth, Wind & Fire have brought wildflowers to Silver Star . United States Forest Service . Retrieved August 14, 2018.
  8. ↑ a b Trails # 180 & # 180D Silver Star & Summit . United States Forest Service . August 2, 2018. Retrieved August 14, 2018.
  9. ↑ KW Wegmann, PT Pringle: Geologic Field Trip to the Aldercrest - Banyon Landslide and Mount St. Helens, Washington, Part I - Stevenson to Castle Rock . Washington State Department of Natural Resources, Division of Geology and Earth Resources, 2004.
  10. ↑ P. Jolotta: Naming Clark County . Fort Vancouver Historical Society, Vancouver 1993.
  11. ^ An Outline of the Geology of Washington  (Washington Public Documents), Volume 3. Washington Geological Survey, 1902.
  12. ^ A b Soil Survey of Skamania County Area, Washington  (= Soil Conservation Service). United States Department of Agriculture , 1990.
  13. ↑ Trail # 180E Indian pits . United States Forest Service . August 6, 2018. Retrieved August 14, 2018.
  14. ↑ a b c Yacolt Burn State Forest . Washington State Department of Natural Resources. 2018. Retrieved August 14, 2018.
  15. ↑ a b Trailhead: Silver Star . United States Forest Service . July 28, 2018. Retrieved August 9, 2018.
  16. ↑ a b c Trail # 180A Ed's . United States Forest Service . August 6, 2018. Retrieved August 14, 2018.
  17. ^ C. Romano: Day Hiking Columbia River Gorge: National Scenic Area / Silver Star Scenic Area / Portland - Vancouver to The Dalles . The Mountaineers Books, 2011.
  18. ^ K. Russell: Explore the PNW: Silver Star Mountain . USA Today . June 26, 2015. Accessed August 14, 2018.
  19. ^ A. Thomas: Big views, lots of wildflowers at Silver Star Mountain . In: The Daily News , August 9, 2012. Retrieved August 15, 2018. 
  20. ^ Trail # 180B Chinook . United States Forest Service . August 6, 2018. Retrieved August 14, 2018.

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