Lakes

The morning of the day the Las Conchas fire started, the air was so hot, the soil so dry I went looking to see if any prickly pear were blooming anywhere this season.

One place I walked was an open field just beyond the near arroyo. Nothing. Not a flower, hardly a healthy plant in a place they bloom year after year.

The Pacheco fire was still burning towards Tesuque and was sometimes visible from the road in the area. I looked that way from somewhere in the center of the field and, besides smoke, saw something I’d never noticed before. The field looked like a great bay that water had washed over from a break in the badlands.

Saturday, when I was in the near arroyo, I wondered how it connected to that open space which it had to border somehow. The bed narrows between five or six foot walls a little beyond the point where water begins channeling itself for the culverts. As I went up stream from there, it turned to the left and suddenly opened into a great, wide expanse with almost no banks.

I remembered something similar in the far arroyo. Yesterday I walked back to refresh my memory. Again, the tall walls make a turn, this time to the right, and a great expanse opens.

I came home to pour over Daniel Koning’s map of the Española quadrangle and I noticed something I’d missed before, that some of the places I’d read as Qay1 were really Qayi.

Qay1 is his code for alliuvial soils laid down in the first phase of the post-glacier Holocene period. The river bottom is Qay2, a younger layer.

Qayi turns out to be some intermediate phase of sand and gravel bands, the very strata I’d noticed along some of the taller walls in the far arroyo. The same pattern appeared in the shallow walls of the great expanses of both arroyos. This is precisely where he’d marked Qayi on the map.

Some passing reference in Ted Galusha and John Blick’s article on Española sedimentation that I’ve slowly been reading sent me to look up the Otowi lava flows they said had dammed the Rio Grande in recent times.

I discovered Steven Reneau and David Dethier’s work on area lakes created when landslides dammed the Rio Grande around the Otowi bridge. One occurred around 43 thousand years ago and created a lake some 15.5 miles long that lasted anywhere from a hundred to a thousand years.

Another landslide created a pool 13 miles long about 17.5 thousand years ago which broke suddenly. The most recent, formed about 12.4 thousand years ago, was also about 15.5 miles long and filled completely with layers of sediment.

During much of this time, the very end of the Pleistocene, there was greater rainfall than now, so the river levels would have been higher. The most recent lake was 100' deep.

This area is well within 10 miles of the Otowi bridge, probably much closer if you’re a crow or a drop of water.

One small mystery has been solved, the origin of those gravel bands. What still is unknown is why the channels that are being opened now in the arroyos and washes were there to be filled by Qay1 and Qayi in the first place.

The River Runs

Wednesday it rained, day and night.

Thursday noon when I went to the post office the river was running higher and faster, the color of caffè latte.

I thought, ah yes, of course, the river’s running. It rained. I didn’t think, I’m seeing the great shaping force of this part of the country roused from a long seasonal slumber.

I didn’t connect even though I’d spent the morning looking at Daniel Koning’s “Preliminary Geologic Map of the Española 7.5-minute Quadrangle” which shows a lopped triangle with the Rio Grande and Route 285 on the sides, the Rio Pojoaque to the south and the Santa Cruz river on the north just above where I was driving over the Griego bridge.

He shows the road near my house skirts what he labels a “geological contact.” The soils to the river side have recent alluvial origins. The ones to the east date back to an earlier Tertiary period. Since the time before the great glaciers when the river began to connect the discrete basins of the rift valley, water has been digging and padding its channel.

It’s removed or redeposited the existing tertiary sediments, or perhaps both at the same or different times, and left a boundary area that needs no geologist to recognize.

I went back to today to the Griego Bridge to see the river at the point the Santa Cruz enters. The current was slower, but the water was still carrying dirt. Gravel and sand have been deposited where the dammed and controlled water flow of the one meets the less tamed Rio Grande.

Then I drove home and looked again at that “geological contact” out the car window. You could imagine the grass as some great sea lapping against dunes. And like ladies of a certain age who once were rivals and now nod when they meet, you can only guess their pasts from the differences in their outerwear, their vegetation.

White Sand

There are things you always say you’re going to do, and something always intervenes.

Every time I drive north towards Taos from Velarde I tell myself I really must pull over on the way back and look. Fallen lava boulders litter the right shoulder as you rise. By necessity, the turn offs are all on the other side. The road has too many blind spots to simply cross over.

But then, when you’re coming home, you’re, well, coming home. It’s a different mental state. There’s never time to pull over.

Well, I finally did it. When I was coming back from the Dixon area a few weeks ago, I pulled over in some of the places between Embudo and Velarde where the rift is narrow, the Rio Grande close to the road.

The look up towards Taos isn’t quite as dramatic as it was when I was driving north - but then it’s like the drive down La Bajada Hill - there are no turn offs when the rocks are the most menacing. The turn offs are only where there’s room, which, by definition, is not where it’s most exciting. Perspective is different from fifty feet across the road.

The river turns out to look like a river there, like any river anywhere in the country where water actually flows and doesn’t simply ripple around sand islands as it does in Española. Nice, unusual actually for New Mexico, but conventional still the same.

Then there’s the unexpected, the thing you didn’t know was there because you never stopped.

In this case, there was a patch of white sand near the river with Russian thistles and purple asters. You think, wait a minute, white sand? New Mexico?

The White Sands in the Tularosa Valley are gypsum dunes. This glittered in the sun. It had to be ground quartz, which of course is as much silica as sand. In fact ground pure quartz provided the material for Venetian glass makers.

Quartz has the greatest weather resistence of any of the rocks in the area. It’s often the last remaining eroded rock from the Sangre de Cristo. This “dune” looks suspiciously like how that sedimentary grey rock I saw earlier in the day beyond Dixon would look if everything soft disappeared and left only the quartz and shining mica. And it photographs the same way, too brown and out of focus, or all glare.