The “Big Slam” Creates Mystical Sierra Madera
‘Man About Texas’ series
By Russell Graves
Special to sportsandoutdoors.guru
FORT STOCKTON — The sight must have been a spectacular.
While estimates vary, sometime around 100 million years ago, the skies above what would later become the dry desert grasslands between Fort Stockton and Marathon, Texas glowed in a brilliant light. Some scientist say that it was a comet while others say it might have been a meteor — either way, something big slammed into the earth and created a enormous scar on the landscape.
Studies indicate the object was as big as a football field. Considering the size of the blemish on the earth, it is remarkable that an object so small can create a scar so enormous. A scar so big – most don’t even know it’s there.
Somewhere on the edge of the desert south of Fort Stockton on US Highway 385, a mountain peak rises curiously from the desert landscape. Detached from the Glass Mountains further south, the singular peak stands juxtaposed in the surrounding landscape of scrub mesquite and a ring of smaller foothills around the periphery. Between the hills and the peak is a big, flat plain of mesquite and creosote bush. In all, the land feature is enormous — about eight miles across.
The mountain, or using a geological term, “central uplift”, is five miles across and rises nearly 800 feet above the desert floor and is only 600 feet shy of towering a mile above sea level. The structure was formed when the extraterrestrial object slammed into the earth, the colossal collision causing the underlying limestone protrude upwards.
Think of it like this: When you drop a stone into water, a crater is first created and then a central peak rebounds in the middle of the crater. This is how Madera Mountain was created.
Unlike the fluidity of water, the hard rock limestone’s peak froze forever in mid-rebound. Now it lies to the east side of the highway as a Texas curiosity.
The feature is so rare, it is the only impact crater of its kind in the U.S. with a central mountain peak and one of the few that you can still drive across. While the peak lies on private property, it is still readily visible from the road. In fact, highway signs signal when you cross into the crater on one sign and herald your exit on the other.
It is truly a fascinating piece of natural history.