Lithospheric drip likely explains how the Green River cut through the Uinta Mountains
Feb 23rd 2026
Seismic imaging and modelling show a dense block of lower crust sank beneath the Uintas 2 to 5 million years ago, lowering the land and letting the Green River carve its canyon and join the Colorado River.
- Researchers identified a cold, round anomaly about 200 km deep and 50 to 100 km across that they interpret as a broken-off lithospheric drip.
- The team estimates the drip detached between 2 and 5 million years ago, matching the period when the Green River cut through the range.
- River network modelling reveals a bullseye pattern of uplift and about 400 metre surface elevation change consistent with rebound after the drip.
- The Green River carved a roughly 700 metre deep canyon through the 4 km high, 50 million year old Uinta Mountains and later linked with the Colorado River.
- The evidence contradicts earlier ideas that the river predated the mountains, overtopped them from sediment, or was captured by southern erosion.
- The study was led by Dr Adam Smith at the University of Glasgow with coauthors from UCL, University of Utah, and the Utah Geological Survey, and is published in Journal of Geophysical Research: Earth Surface.