Sometimes the forces that build mountains are most evident in the foothills, not the mountains themselves.

The cores of many Rocky Mountain uplifts are a mess of metamorphic rock, ancient and beat up beyond recognition. But along the flanks of the Front Range — at well-known geology stops like Red Rocks, or Dinosaur Ridge — the sedimentary rocks are tilted and bent in response to the same processes that formed the tall peaks just a stone’s throw to the west.

Red Mountain Open Space, just 25 miles north of Fort Collins, Colorado, may not have the same name recognition as other geologic must-sees in the area, but it’s a near-perfect example of the geologic structure called an anticline.

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Red Mountain Open Space as seen from up on the Cheyenne Rim Trail.

An “anticline” refers to a bell curve-shaped bend in rock layers. (An anticline looks a bit like its first letter, a capital “A,” with tilted rock layers on either side, as opposed to a syncline, which looks more like a “U.”) Most rock layers are originally laid down on relatively flat surfaces: river floodplains, beaches, deltas, the open ocean. When these layers are buried, they become far less brittle than rocks at the surface — in fact, they can bend.

And I can think of no better example of the slow power of tectonics than an ancient beach lifted thousands of feet into the air and literally bent in half.

Bent Rock Trail is, not surprisingly, the best trail for getting up close and personal with the anticline at Red Mountain. The trail does a quick two-mile loop around the the core of the structure.

The anticline as seen up-close along Bent Rock Trail.

The best overall view of the anticline, however, is from way up on the Cheyenne Rim, where the High Plains of Wyoming drop down to the Colorado Piedmont. From the rim, you can clearly trace the bent layers in the deep maroon of the Lykins Formation. In the midground, tilted rocks on the either side of Ruby Wash form the limbs of the anticline – here the center has eroded away. In the distance, Table Mountain is actually a chunk of mostly-eroded syncline, where the rock layers begin to bend back in the other direction.

After about a thousand-foot climb up onto the Cheyenne Rim, hikers are treated to a completely different sort of landscape: the High Plains.

After about a thousand-foot climb up onto the Cheyenne Rim, hikers find a completely different sort of landscape: the High Plains.

If you’re feeling like a nice long hike, tackle the loop up onto the Cheyenne Rim and back down Ruby Wash (bikes and horses are allowed if you don’t have all day). This route gives fantastic views of not only the anticline but also the crest of the Front Range to the west and the gently rolling Wyoming prairie to the north.

Getting to Red Mountain Open Space:
From Fort Collins
Take State Route 1 (Terry Lake Road) north out of town. Continue straight onto County Road 15, toward Douglas Reservoir, for about ten miles. Then the zigzag: turn left onto County Road 78, drive a mile, turn right onto County Road 17, drive another mile, turn the corner onto County Road 80, and finally turn right onto County Road 19. A little over a mile later, make another left, and continue on County Road 21 for eight miles to the trailhead.

From Laramie
Take US-287 south. About two miles south of Cherokee Park Road, and one mile north of Livermore, CO, turn left onto County Road 80. Travel east about eight miles on this dirt road, and then turn left onto County Road 19. A little over a mile later, make another left, and continue on County Road 21 for eight miles to the trailhead.

From Cheyenne
Head south on Interstate-25. Take exit 288 and head west on County Road 82. In about six miles, make a right at the T-intersection onto County Road 15. In a mile, turn left onto County Road 84, and follow this about two miles to County Road 21. Turn right, and continue for eight miles to the trailhead. Alternatively, turn left onto County Road 15 (south) at the T, and follow the zigzag in the Fort Collins directions.

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