A mountain with a steep canyon through it is a geological puzzle – why would a river take the hard way to get to the other side of a mountain? Why not just go around? The key is knowing the time sequence.
We just spent a few days near the fancifully named Gates of Lodore at the downstream end of an 18-mile long canyon through the appropriately named Split Mountain on the Green River near Dinosaur National Monument in northeast Utah, just south of the Unitas Mountains. John Wesley Powell and his crew explored this area and named the feature in their typical 19th century romantic style, after a poem by Robert Southey.
All these deep canyons through an arid wilderness are an irresistible lure for whitewater rafters, and a whole industry has sprung up around the logistics of getting groups of rafters outfitted, dropped off at the upstream end, and sheltered and fed during their three or four day trip down the river. It loops over into northwestern Colorado, where the actual Gates of Lodore are, and on down to where the Green River joins the Colorado. The kayaking part is through these mountains.
But back to the geological mystery – why didn’t the river just avoid the area entirely on its quest for an easy drainage? The answer is uplift. The Colorado Plateau has been on the move for millennia – upward. And the river was here first. As the land rises, the river carves downward into it, maintaining its gradient. Since erosion is faster than uplift, Split Mountain grew up smack in the path of the Green River, which cut a slot through the middle of it as neatly as a table saw cuts wood.
The Grand Canyon is the best-known example of a river carving into an uplifting plateau, but there are plenty more – Goosenecks State Park near the Four Corners area is another, where the San Juan River cut a thousand feet into the plateau in order to continue its march to the sea. As soon as the river cuts down to the depth it needs to maintain its gradient, erosion stops. Take an altimeter on a trip down the river, and you will see a smooth decline in altitude from top to bottom, regardless of the ups and downs of the terrain you’re traversing. It may be uneventful down at the river level, but the opportunity to see all the exposed strata sure makes for a good kayaking trip.
There’s BLM camping throughout Dinosaur National Monument, $8-12 a day and half price with a senior pass. No hookups, but water and fire rings, maybe a picnic table too. Some of the campsites are overrun with kayakers so choose carefully. As in all riparian environments, you’ll see a concentration of wildlife exploiting the riverside food and shelter provided by the cottonwoods and other plant growth. Vernal, Utah is the nearest decent sized town to stock up on supplies, but there’s always fuel and limited food available all over the area.
Comments are closed.