Mima Mound with Rock Ring

Mima Mounds - A Mystery on the Shaniko Plateau

In our scientific age, it’s hard to believe that the origins of any landform could still be unexplained, but this is the case with the extensive soil mounds and their encircling rock rings found northeast of Madras on the Shaniko Plateau. Known as mima (my-muh) mounds, several theories have been advanced about their formation, from differential erosion, to Ice Age freeze-thaw cycles, to soil movement by foraging gophers. But no one theory is widely accepted and these unusual land features remain a puzzle to geologists today. Hundreds of acres of this mima mound topography can be explored on BLM land near Shaniko.
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Panoramic Photo of Tumuli Lava

Tumuli Lava - A Backdoor into the Badlands

What are tumuli (besides the plural of tumulus)? From the Latin tumidus, meaning swollen or bulging in shape, a tumulus is a circular, domed lava structure up to 30’ high and 60’ in diameter, formed by the upward pressure of actively-flowing lava against its cooling crust. Along with its elongated cousin, the pressure ridge, these fascinating lava formations can be explored on a less-traveled trail in the Badlands Wilderness, just 15 miles east of Bend.
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Panoramic View of Sand Canyon

Pinnacles of Wheeler and Sand Canyons

Some of the more geologically and visually interesting canyons in Central Oregon are found on the southeast slopes of the Crater Lake caldera. In these lightly-visited canyons are found hundreds of stark stone pinnacles, which have eroded out of the volcanic ash of remnant Mount Mazama. The pinnacles in Wheeler Canyon are easily accessible by car at a viewpoint in Crater Lake National Park, while the rock towers in lower Sand Canyon require a challenging, cross-country bushwhack of 2.7 miles roundtrip.
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Panoramic View of Ponderosa in Kipuka

Kipukas - Forest Islands in a Sea of Lava

One of the more interesting geologic features of Central Oregon are kipukas (meaning “a variation or change in form” in the Hawaiian language). These are islands where lava has surrounded patches of older terrain, isolating them from the surrounding landscape. It’s hard to imagine a more dramatic contrast between the dry, rocky, barren fields of lava surrounding the relatively moist, shady islands of forest.
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