Trials or Trails?

This week’s quest to find a suitable area for a day hike led us to a familiar area of BLM land known as the San Ysidro Trials. I once thought it was a misspelling and was supposed to be San Ysidro Trails. But it’s “Trials” because a large section of it is used for recreational motorcyclists (aka ‘dirt bikes’) who want to test their expertise riding in and around the rocky arroyos in the area. Fortunately, during the times we have hiked there we haven’t encountered any of the roaring, noisy machines, although it’s obvious from their tracks that it is well used.

When we go there we like to walk past the trials area and get to a section of eroded sandstone that, even on a cloudy day, has colorful and interesting rock formations. As wet as the desert still is, we knew we probably would have to navigate through some muddy spots before we got to the rocks. But the parking area is right off a paved highway so we didn’t have to drive any muddy roads. In the spots where the trail got muddy we were able to pick our way through spots of grass along the trail.

This landmark lets us know we are crossing the arroyo in the right place. Look closely to see the “monkey face” rock.

Another reason we like hiking in this area is to check out the many tinajas. “Tinaja : a bedrock depression that fills with water during the summer monsoonal rains and when snowfall accumulates in the winter.” We’ve had a winter with snow accumulations and the tinajas didn’t disappoint. Here are a few of the interesting ones.

Quebradas Sediments

A few weeks ago when we did a hike in the Manzano Mountains I got carried away taking pictures of rocks along the trail. The wavy, layered metamorphic rocks that are abundant in the Manzanos look to me like beautiful pieces of artwork. I couldn’t resist posting some of my photos here.

Yesterday we were hiking in another area that compels me to take pictures of rocks. We were in the Quebradas, this time not an area of metamorphic rocks, but, instead, mostly sedimentary rocks. But sedimentary rocks form in layers, also, and with the fractures, folds and faults that occur on the earth’s surface many sedimentary rocks end up with fascinating shapes and patterns.

In addition to folding and faulting that reshapes the sediments, sometimes there are certain chemical processes that change the colors of the rocks in interesting ways. I don’t know all of the details, but in the laboratory of the geology class I recently completed, I remember the instructor explaining the round white dots in some reddish sandstones as places where a chemical impurity in the sandstone as it was being oxidized (changing it to the reddish color) would prevent the oxidation, leaving a white space around the impurity. There were many rocks in the Quebradas that had that feature and I photographed several samples.

Quebradas is a Spanish word meaning “breaks,” a rugged or rocky area. The BLM owns most of the land along the Quebradas Back Country Byway, a 24-mile dirt road east of Socorro that parallels I-25. There are 10 numbered stops, places along the way to park and observe various geologic features. Official hiking trails are nonexistent–you just wander anywhere in the vast emptiness that happens to capture your interest.

We parked at Stop 4, which is in the upper reaches of the Arroyo del Tajo. A nice hike that we have done before is to walk about 2-1/2 miles down the arroyo, observing the rocks (in Lee’s case observing the wildflowers, which are few and far between this time of year) and then rounding a corner to find yourself in this amazing slot canyon.

Walking out the other side leads to a nice ledge to stop and have lunch, which is what we did, before turning around and retracing our steps back to the car. Altogether an enjoyable winter hike.