Dirk OdenDirk Oden



About SP
Science Humor





Dikes of the Spanish Peaks Still Stand the Test of Time

      For anyone who has coasted into Walsenburg from the top of La Veta Pass, the Spanish Peaks are a familiar sight  A double-dose of rugged beauty, the twin peaks dominate the surrounding landscape. I hope, as long as I live in this area, that I never take the unparalleled views for granted. Surely the Spanish Peaks offer one of the most spectacular vistas anywhere.

      I suppose each time I drive by the peaks, I should be inspired to ask deep questions about the meaning of life and contemplate my existence in the universe. As poetic as those snow-capped ridges may be, though, I find my attention is always diverted to a few odd formations at the base of the peaks. The only question that comes to mind is, "What are those darned things?"  

Mysterious walls

      I'm referring to those long, thin, vertical rock walls that rise up out of the ground. Like spokes on giant wheel, they radiate outward in straight lines from the base of the Spanish Peaks. Are they great walls erected by an ancient civilization? Do they point to some secret alien refueling station inside the peaks? (Hey, it's only 270 miles from Roswell!) Or are they natural? And, if so, why are they so tall and thin? Why do they stick up out of the ground? How did they form?

      As it turns out, the walls are quite fascinating, but not much of a mystery. They are natural, of course, and provide one of the best known examples of interesting geological structures known as "dikes." In fact, the Spanish Peaks dikes are often featured in geology textbooks because they so prominently illustrate the concept. 

Looking back

      To understand how the dikes of the Spanish Peaks were formed, we must go back in time. Ninety million years ago, the eastern two-thirds of what is now Colorado was covered with a shallow sea. The western third, where land was slightly higher than the sea, consisted of coal swamps and floodplains. Over time, the seas receded as land rose during the birth of the Colorado Rockies. 

Twins are born

      The Spanish Peaks formed when twin pools of magma (hot, liquid rock) began pushing their way up towards the surface. The older, overlying rock bent and slowly rose over each pool as the magma pushed upward forming two large, dome-shaped humps. The magma never quite forced its way through the overlying rock to spew onto the ground forming a volcano. Still, the pressure on the older rock was so intense, huge cracks formed beneath the surface that radiated outward from the domes. (Much like a rock chip in a windshield may send cracks out in all directions without completely penetrating the windshield.) Molten rock squeezed into the cracks and then began to cool and harden.  

A vanishing world

      Over time, the slow but powerful force of erosion began carving away on first the older, overlying rock and eventually the newly exposed hardened magma. But the hardened magma was (and still is) stronger than the softer surrounding rock. It has eroded at a slower rate and now stands above the rock which once hid it. More than just geologic oddities, the dikes are a reminder of another world--one separated from us by the distance of time.  

Worth the drive

      A number of dikes can be easily seen in the distance from Highway 160 on the way in to Walsenburg. But for a close-up look at several of the dikes, and for a scenic and interesting drive in general (a sharp eye will likely be rewarded with the sight of wild turkeys), take Highway 12 out of La Veta to Trinidad. At the town of Stonewall you will drive right through a thin, vertical rock wall. This particular wall, though, is not a dike. It is made of older sandstone tilted up on its side from the awesome forces of mountain building millions of years ago. As you near Trinidad, you will begin to notice seams of coal in the exposed roadcuts, evidence of the swamps existing in the area before the mountains formed. Some of the numerous old coal mines in the area are still active.

A lesson from the dikes

      Whether or not you someday drive scenic Highway 12, the next time you find yourself coasting down La Veta Pass towards Walsenburg, take a good look at the dikes in the distance. While their natural history is interesting, their significance lies in what you don't see when you look towards the Spanish Peaks. The dikes are visible only because a past world has been washed away. As Gus McCray said in Lonesome Dove, "Yesterday's gone and you can't get it back." If the sight of the dikes inspires you to ask a question, I hope it is, "What will I do, while it is still today?"


This site was last updated 09/05/06