Colorado National Monument
Red Wingate canyons and monoliths — Independence Monument, the Coke Ovens — cut into the Uncompahgre Plateau above Grand Junction, floored by 1.7-billion-year-old basement.
Colorado National Monument is a landscape of sheer-walled red canyons and free-standing monoliths carved into the edge of the Uncompahgre Plateau above Grand Junction. Cliffs of Wingate Sandstone (capped by the Kayenta Formation) rise straight off a floor of dark Proterozoic gneiss and schist, so the monument's walls telescope from 1.7-billion-year-old basement to Mesozoic desert sandstone in a single view. Monoliths like Independence Monument and the Coke Ovens stand where the canyon walls have been eaten back around them.
Geology
Formation: Cliffs and monoliths eroded from cliff-forming Wingate Sandstone (capped by the resistant Kayenta) above a nonconformity on Early Proterozoic gneiss and schist; canyon cutting was driven by uplift of the Uncompahgre Plateau and incision of the Colorado River.
One of the clearest places to see the Great Unconformity-style contact between ~1.7-billion-year-old crystalline basement and overlying Mesozoic sedimentary rocks, exposed in accessible canyon walls.
Primary formation: Wingate Sandstone
Age: Jurassic (200 Mya)
Independence Monument is a free-standing Wingate spire; the basement here belongs to the same Uncompahgre uplift exposed in Westwater and Ruby-Horsethief canyons.
History
Established as a national monument in 1911, largely through the advocacy of John Otto.