The Owyhee Mountains are a mountain range in Owyhee County, Idaho and Malheur County, Oregon .
6-860: Mahogany Mountain and the associated volcanic craters of the Lake Owyhee volcanic field are in the Owyhee Mountains of Oregon just east of the Owyhee Reservoir on the Owyhee River . The southeastern end of the range including the old mining area west of Silver City is referred to as the Silver City Range. About 8.3 kilometres (5.2 mi) west of Silver City is the De Lamar ghost town in Jordan Creek below
12-591: A fishing and camping ground for early Native Americans. The climate of the area tends to be extreme; that is, it is cold in the winter and hot in summer. Sparse vegetation is present, including shrubs and patches of juniper . A part of the Basin and Range Province , the volcano's most recent eruptive activity dates to approximately 15 million years ago (the Miocene ), forming during a period of active volcanism including eruptions of ignimbrite and ash . It formed around
18-531: Is an ancient caldera volcano on the border of Oregon and Idaho , in Malheur County and Owyhee County , respectively. While its early history is largely unknown, its last eruption was probably 15.5 million years ago. This eruption ejected layers of rhyolite and produced tuff , creating formations of rock in the Leslie Gulch . Nearby features include the Owyhee River , historically used as
24-430: The formation, and leftover volcanic rocks sit in it as well. The gulch features an array of rock formations and ash erupted from the volcano approximately 15.5 million years ago. The nearby Owyhee River was utilized by Native Americans as early as 5,000 years before European habitation of the area. It served as a source of food, both for fishing and hunting, and the natives often camped along its banks. The area by
30-545: The mine workings on De Lamar Mountain to the south. The area was active in the late 1880s. In the 1970s mining began again with the development of open pit silver – gold mines on De Lamar Mountain. This Owyhee County , Idaho state location article is a stub . You can help Misplaced Pages by expanding it . This Malheur County , Oregon state location article is a stub . You can help Misplaced Pages by expanding it . Mahogany Mountain Mahogany Mountain
36-434: The same time as Three Fingers , Castle Peak , and three other volcanoes. Today the volcano appears gnarled due to erosion and is topped by pine forests. The caldera is narrow and shaped like a ridge, with precipitous slopes and an escarpment on the northwest flank. It consists of rhyolite tuff and sedimentary layers. Leslie Gulch lies within the depression of the volcano. Layers of ash and tuff are evident in
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