Geological Points of Interest in the Stehekin Valley
Lake Chelan National Recreation Area
North Cascades National Park Service Complex
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Sculptured Rocks and Slickensides Location: Sculptured Rocks - 3 miles upvalley from High Bridge; Slickensides - Last large roadcut before Shady Camp 3.4 miles upvalley from High Bridge |
 Slickenside |
These two sites illustrate different aspects of the formation of the Stehekin Valley. Slickensides are polished and striated rock surfaces that result from friction along a fault trace. This illuminates the reason that the Stehekin River has formed a valley here: the rocks along this fault have been weakened by the grinding action of the fault zone and are more easily eroded than other rocks. The river flows and erodes its valley along the easiest path. Sculptured rocks, illustrated below, are produced by the erosive action of the river itself. The passage of millions of gallons of water and the grinding of sand and gravel carried by the river polishes and sculpts the under lying bedrock. The fact that these rocks are well above the highest flood stage of the present river demonstrates the continuous downcutting of this powerful river.
Slickensides
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