Born in Fire, Dying in the Wind
The peaks of New Mexico’s Rio Puerco Valley are all old volcanic necks. The region was once an extensive volcanic field, where columns of magma thrust up through the sedimentary rocks of the Colorado Plateau. The volcanoes themselves are now long gone, the soft cones of their outer slopes eroded away, leaving only their basalt hearts standing like obelisks.
The valley has dozens such formations, no two quite alike. On the left in this image is graceful Cerro Cuate (Twin Peak); further away, massive Cabezon Peak towers over the landscape. Between lie miles of empty rangeland, Mancos Shale badlands, valley bottoms cloven by deep twisting arroyos with unstable walls of crumbling mud. The country also contains several ghost towns, settled by the Spanish in the mid-18th Century, abandoned in the 1930s. A few folks still live in San Luis near the highway, but the area was substantially more populated a century ago than today.
Even at a distance, Cabezon dominates this country:
Remarkably, geologists say that many of these enormous structures have only a tiny connection to the magma beneath:
The large diameter and vertical height of the volcanic necks above the valley give the impression that they are exposed tips of masses that plunge straight down as massive cylinders of basalt. In reality, there are many lines of evidence that most of the necks are simply large masses of basalt that rapidly narrow downward to feeder dikes measuring less than a few feet wide.
–The Geology of Northern New Mexico’s Parks, Monuments, and Public Lands, pg. 63
This is a cold desert though, and the previous week was the hardest in decades. This little guy apparently froze in his tracks:
A winter storm moves in over Cabezon: