The Great Desert


Friday, our first stop was at a roadside 'waste repository' beside US 550. From there we had great views of the Sandia Mountains, the the Valles Caldera and the San Filipe volcanic field. Dr. Ferran Garcia-Pichel took that opportunity to talk about life in desert environments, particularly cyanobacteria-rich crusts in desert soils


From the Desert Soil site, looking north into the Jemez mountains. Across the freeway, the badlands landscape is cut into sands and muds of the Santa Fe group (Tertiary-age sediments that fill the Rio Grande rift trough). The Santa Fe sediments are folded slightly into an anticline (concave downward). This deformation happened as the Rio Grande Rift continues to open. The whitish band at the top of the badlands hillslope is caliche soil - dirt enriched in calcium carbonate. Credit.
Dr. Ferran Garcia-Pichel describes the desert crusts at this site. This place was chosen for the view and not the soils, so it seems reasonable that the cyanobacterial crusts there are typical of desert soils throughout the southwest. Credit.
Ant Hill

We dug this small hole in the sandy desert soil, and it is clear that the topmost few centimeters of the soil sticks together, while the underslying sand just falls down into loose slopes. On Saturday, we looked at this soil through the microscope, and saw the many bacterial filaments that hold it together. Other vegetation in the area was mostly bunch grass (as in this scene), rabbitbrush (wormwood), and mesquite. Credit.
Another biological effect, but not likely on Mars. Larry Crumpler (NM Museum of Natural History) annoys big red ants at their hilll. A young cholla cactus looms behind him. Credit.
Ant Hill

More biology. A small hornless "horny toad". Credit.
The Zia Pueblo. Credit.

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Copyright Allan Treiman, LPI.
Updated 11/21/03.
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