The Nambé Badlands and the Sombrillo Area of Critical Environmental Concern

The Nambé Badlands are located north of the Village of Nambé, northwest of the Nambé Pueblo, and south of Chimayó, New Mexico.  They consist of a labyrinth of arroyos and canyons in a piñon-juniper landscape.  Many first see these badlands when they travel on “The High Road to Taos” (SR 503) south of Chimayó.

These federal public lands are managed by the Bureau of Land Management Taos Field Office.  The land on the west side of NM 503 contains an 18,008-acre special area, the Sombrillo Area of Critical Environmental Concern (ACEC).  In 1988 this portion of the greater Nambé Badlands was designated an Area of Critical Environmental Concern to protect significant paleontology resources (vertebrate fossils from the Miocene Epoch 23.0 Ma – 5 Ma), and to protect archeological resources in the area.

Wildlife use the Nambé Badlands as an important corridor between their higher and lower elevation habitats.  High cliffs of sedimentary deposits (Tertiary Lower Santa Fe Group[1]https://geoinfo.nmt.edu/publications/maps/geologic/state/home.cfml)  provide vital nesting areas for many species of raptors.

The area was inhabited long ago by early Native Americans, as evidenced by cultural archeology in the badlands.

The sedimentary unit that fills the Nambé Badlands is known as the “Tesuque Formation.” It preserves the fossils of many vertebrates that lived in the area during the Miocene Epoch (~ 14.5 million years ago).  The Tesuque Formation[2]https://geoinfo.nmt.edu/publications/maps/geologic/ofgm/downloads/54/OFGM-54_EspanolaReport.pdf is comprised of conglomerate, sandstone, mudrock, and limestone of non-marine origin, with numerous interbedded ashfall-tuff layers.  The Nambe Badlands is rich in fossils and was explored extensively by paleontologists from the American Museum of Natural History from 1924 – 1964.

Aerial photograph of the Nambé Badlands looking northeast (2017).  NM 503, “The High Road to Taos”, is the two-lane highway seen in this photo.  The Sangre de Cristo mountains are seen in the distance.  The Nambé Badlands are shaped from alluvial deposits and runoff from the Sangre de Cristo.

Overview map of the Nambe Badlands Showing Trails that Existed Before 2011

This map shows the property ownership in and around the Nambé Badlands.  Trails as of 2011 used by hikers, equestrians, and mountain bikers are shown in green; blue trails indicate trails primarily used by hikers.  Details on these trails can be found here.

One of the key features of this landscape is fragile cryptobiotic soil crusts over the soft and sandy soils. These cryptobiotic (crypto = hidden, biota = living) crusts protect the arid desert landscape from massive erosion due to wind and water runoff.

The land in the Nambe Badlands is highly erosive compared with most semi-arid landscapes.  Underneath the fragile cryptobiotic crusts that are widespread in the Nambe Badlands are poorly consolidated sands and fine-textured silty soils with a flour-like consistency.  These soils cannot support the weight of a human or bicycle without being compressed and displaced.  Every footstep breaks up the cryptobiotic crusts and leaves a permanent scar, with the fine powder soil then exposed to the erosive elements of water, wind, and freeze-thaw processes.  Trails also concentrate water flows, thereby greatly amplifying soil erosion.

Thus travel in the Nambe Badlands has the potential to greatly damage these extensive cryptobiotic crusts and underlying fine-textured soils.  In many other semi-desert environments, the percentage of ground covered by fragile cryptobiotic crusts and easily eroded soils is lower than in the Nambe Badlands, such as in the Moab area where extensive exposures of hard sandstone bedrock allow for travel with less harmful impacts.  Unfortunately, that is not the case in the Nambé Badlands.

Cryptobiotic soil crust in the Nambe Badlands, New Mexico

Cryptobiotic soil crust in the Nambé Badlands. These crusts are alive with cyanobacteria, as well as lichen, moss, fungi, and other bacteria.   They hold the soil together and prevent massive erosion from wind and water runoff.

Cryptobiotic soil crusts are not the only fragile resource in the Nambé Badlands.  The geology of Nambé Badlands is a critical resource to paleontologists due to significant finds of vertebrate fossils from the Miocene Epoch (23 – 5.3 million years ago)  in the Tesuque Formation (conglomerate, mudstone, sandstone, and other sedimentary layers).  Famous paleontologists, like Edward Drinker Cope, have discovered new (extinct) species of mammals from fossil finds in the Nambé Badlands.  The area was first explored by paleontologists like Cope in 1874 when he discovered 32 new species.

Because the Nambé Badlands is so rich in Miocene fossils[3]Vertebrate Paleontology in New Mexico, New Mexico Museum of Natural History & Science, 2015, Bulletin 68, page 163, it was designated as the Sombrillo Area of Critical Environmental Concern (ACEC) in 1988.  The BLM Sombrillo ACEC covers the BLM land on the west side of NM 503.

Read more about the fossil records in the Nambé Badlands here.

Mural by Rudolph F. Zallinger, “The Age of Animals” showing reconstructions of Miocene mammals.  Fossils of many of these mammals have been found by paleontologists in the Nambé Badlands, Sombrillo Area of Critical Environmental Concern.   Yale Peabody Museum of Natural History.

Fossil of Sthenictis

Fossils of the extinct species Sthenictis a large member of the mustelid (weasel) family have been found in the Nambé Badlands[4]Phil Gensler, Gary Morgan, Scott Aby, and Garrett R. Williamson, “New Additions to the Miocene Vertebrate Fauna of the Tesuque Formation, Española Basin, New Mexico, in Paleontology on Public … Continue reading.   Photo credit, Ryan Somma, Creative Commons license.

The Sombrillo Area of Critical Environmental Concern (ACEC) was designated in 1988 to protect important fossils that have been vital in researching mammals during the Miocene epoch (23.o – 5.3 million years ago).  [5]DOI-BLM-NM-F020-2019-0007-EA, BLM Travel Management Area, Draft Environmental Assessment, May 2020, Appendix E.  Figure 3.11.1.

References

References
1 https://geoinfo.nmt.edu/publications/maps/geologic/state/home.cfml
2 https://geoinfo.nmt.edu/publications/maps/geologic/ofgm/downloads/54/OFGM-54_EspanolaReport.pdf
3 Vertebrate Paleontology in New Mexico, New Mexico Museum of Natural History & Science, 2015, Bulletin 68, page 163
4 Phil Gensler, Gary Morgan, Scott Aby, and Garrett R. Williamson, “New Additions to the Miocene Vertebrate Fauna of the Tesuque Formation, Española Basin, New Mexico, in Paleontology on Public Lands, 25th Annual Tate Conference, and 11th Conference on Fossil Resources, May 30-June 2, 2019, Casper Wyoming
5 DOI-BLM-NM-F020-2019-0007-EA, BLM Travel Management Area, Draft Environmental Assessment, May 2020, Appendix E.  Figure 3.11.1.
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