Wallowa Mountains | |
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The Wallowas from Mount Howard. Hurwal Divide is in the front and center, and Sacajawea Peak is behind and to the left. Matterhorn is on the far right.
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Highest point | |
Peak | Sacajawea Peak (Eagle Cap Wilderness, Wallowa County) |
Elevation | 9,838 ft (2,999 m) |
Coordinates | 45°14′42″N 117°17′33″W / 45.24500°N 117.29250°W |
Dimensions | |
Length | 40 mi (64 km) NW–SE |
Geography | |
Country | United States |
State | Oregon |
Counties |
Wallowa Union |
Range coordinates | 45°12′00″N 117°19′04″W / 45.20000°N 117.31778°WCoordinates: 45°12′00″N 117°19′04″W / 45.20000°N 117.31778°W |
The Wallowa Mountains are a mountain range located in the Columbia Plateau of northeastern Oregon in the United States. The range runs approximately 40 miles (64 km) northwest to southeast in southwestern Wallowa County and eastern Union County between the Blue Mountains to the west and the Snake River to the east. The range is sometimes considered to be an eastern spur of the Blue Mountains, and it is known as the "Alps of Oregon". Much of the range is designated as the Eagle Cap Wilderness, part of the Wallowa–Whitman National Forest.
The range is drained by the Wallowa River, which flows from the north side of the mountains, and its tributary the Minam River, which flows through the west side of the range. The Imnaha River flows from the east side of the range.
The highest point in the range is Sacajawea Peak, which is 9,838 feet (2,999 m) above sea level. Sacajawea is the sixth highest mountain in Oregon and the state's highest peak outside of the Cascade Range.
Many geologists believe that the Wallowa Mountains in northeastern Oregon are a displaced fragment of the Insular Belt. The core of the Wallowas is composed of the Wallowa Batholith surrounded by Columbia River basalt. In addition there are many older terranes between the batholith and basalt flows.
The Wallowa Batholith is formed of granite from a magma upwelling in Late Jurassic and Early Cretaceous time (between 160 million and 120 million years ago). The placement of this rock caused uplift of the surface, which at the time was tropical sea. This is evident from the slate, quartzite, and marble present in the mountains, which come from metamorphism of the sedimentary deposits of oceans during the Triassic. At the center of the Batholith are granodioritic rocks, while the outer limits of the range are tonalitic. The granite batholith is cut by dikes; however, these are uncommon.