Named for a long-vanished Gorge settlement near Mosier, the Ortley Thrust is a prominent upward fold in the massive bedrock of Columbia River Flood Basalts that form the walls of the Columbia Gorge. Here, the once-horizonal layers of lava have been pushed upward by enormous tectonic pressures that have created uplifted ridges across this part of the Columbia Basin. The river has been here longer than both the ancient basalt flows and subsequent geologic uplift, keeping pace as it continually carves its channel through the slowly rising land around it.
The Ortley Pinnacles are part of the larger thrust formation, marking a seam between two major flood basalt groups. The flat basalt flows here have been turned on end from the uplift pressure. In much more recent geologic time, a series of massive ice age floods scoured the Gorge walls, stripping away loose rock to reveal the rugged maze of vertical basalt spires and fins we see here today. In early spring, emerging wildflowers paint up the slopes in shades of green while Bigleaf maple blossoms provide the bright yellow highlights.
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Image Description: A series of jagged, rocky basalt fins and pinnacles at center rise against steep slopes covered with the spring green of emerging wildflowers. Bigleaf maples are sprinkled across the slopes, marked by their bright yellow spring blossoms.
Photo © WyEast Images (2026)
WyEast Images 
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