Twin Sisters Mountain
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| Twin Sisters Mountain | |
|---|---|
 As seen from southern flank of Mount Baker |
|
| Elevation | 7,020 feet (2,140 m)[1] |
| Location | Washington, USA |
| Range | Cascade Range |
| Prominence | 3,520 ft (1,070 m)[1] |
| Coordinates | Coordinates: [2] |
| Topo map | USGS Twin Sisters Mountain 48121-F8 |
Twin Sisters Mountain is a mountain in the U.S. state of Washington. Part of the Cascade Range, it lies just southwest of Mount Baker. Of its two main peaks, South Twin is higher, at 6,940 feet (2,115 m) (its elevation is given by Peakbagger.com as "between 7000 and 7040 feet (40-foot closed contour)").[1] North Twin is 6,660 feet (2,030 m) high (its elevation is given by Peakbagger.com as "between 6640 and 6680 feet (40-foot closed contour)").[3] There are several glaciers on the northeast slopes of Twin Sisters Mountain.
Contents |
[edit] Summits
Both of the summits are located within Mount Baker Wilderness. Twin Sisters Mountain as a whole is located southwest of Mount Baker, separated from the volcano by the Middle Fork of the Nooksack River. The South Fork Nooksack River flows around the southern end of Twin Sisters Mountain. Other streams that drain Twin Sisters Mountain include Skookum Creek, Sister Creek, Green Creek, and Howard Creek. All the streams eventually end up in the Nooksack River.[4]
[edit] Geology
Twin Sisters Mountain is composed of Twin Sisters dunite[5], an ultramafic rock that is mostly olivine. This dunite is part of the so-called Bell Pass Mélange: the rock originated deep in the mantle, and then was smashed up against the North American plate in a complex process when island arcs and ocean floor were accreted because of a subduction zone.[6]
[edit] References
- ^ a b c South Twin, Peakbagger.com
- ^ USGS GNIS: Twin Sisters Mountain
- ^ North Twin, Peakbagger.com
- ^ (2000) Washington Road & Recreation Atlas. Benchmark Maps.
- ^ Generalized Geological Map of the Mount Baker 1:100,000 Quadrangle. North Cascades geological map. USGS. Retrieved on 2007-07-16.
- ^ Rocks of the Western Domain. USGS Geology in the Parks. USGS. Retrieved on 2007-07-16.
