Survey of Bears Ears National Monument

Editor’s note: ReBecca Hunt-Foster, District Paleontologist for the Canyon Country District of the BLM  in Southeastern Utah, encouraged interns and other scientists working with her in the summer of 2017 to write articles for us. This is one of three articles we received. We thank ReBecca and the authors for their contributions and encourage all scientists and students to consider the FOSSIL Project as an outreach opportunity.

By M. Allison Stegner, Post-doctoral Research Scientist

Allison Stegner assisting with the excavation of Dytrophaeus, San Juan County, Utah. Photo credit: ReBecca Hunt-Foster, 2016

Southeastern Utah has been an internationally important region for paleontology as far back as the 1800’s, and the designation of Bears Ears National Monument (BENM) is an opportunity to reflect on the unparalleled fossil resources in this area, and to devote new efforts to understanding and protecting those resources. I have studied Quaternary vertebrate sites in the area now known as BENM for half a decade. This June, I began work as an intern paleontological resource assistant for the Bureau of Land Management, conducting surveys of regions in BENM that are characterized by outcrops which are known generally to be fossiliferous, but which have received little research attention to date. By and large, these are the most remote corners of BENM where fossil prospecting requires long drives on bad roads, and miles (both horizontal and vertical) of hiking and clambering over boulders, scree slopes, and arroyos.

Sedimentary geology, uplift, and erosion have converged in southeastern Utah to create a landscape in which exposed outcrop is progressively younger as you proceed eastward from the Colorado River toward the Colorado-Utah border. In the Permian Cutler outcrops on the western side of BENM, we have the potential to find burrows, petrified wood, trackways, and vertebrate bone from various fishes, sharks, and amphibians. While the southern corner of BENM is dotted with Triassic Chinle, further north, Chinle is one of the predominant outcrops: the iconic Wingate cliffs along the Indian Creek corridor are aproned by substantial Chinle slopes. In the Chinle of BENM we find amphibians, dinosaurs, phytosaurs, traces from aquatic life, and delicate plant fossils. We find bivalves, as well as dinosaur bones and tracks in Jurassic Navajo, Kayenta and Morrison formations of BENM. The regions we know best are, not surprisingly, closest to highway 191, that extends from Crescent Junction (east of Green River, Utah), down to the Arizona border, and near Highway 95, which connects Blanding and Hite by way of the Comb Ridge. These areas produce new fossils and new localities every year. However, because these regions have been the focus of past and on-going research, my surveys this summer have concentrated on three regions that have not been well-studied: the Permian (Cutler) and Triassic (Moenkopi and Chinle) outcrops south of the Dark Canyon/north of Natural Bridges National Park; the Chinle outcrop near Cathedral Butte, west of the Abajos and east of the Canyonlands NP Needles District; and the Cutler and Chinle outcrops that skirt Beef Basin and the north edge of the Dark Canyon Plateau.

 

Triassic petrified wood in Bears Ears National Monument. Photo credit: Allison Stegner, 2017

 

I have also been scouting for Quaternary sites collected by packrats. The taphonomy of these sites is a little unusual: mammalian and avian carnivores eat small vertebrates, and identifiable bone fragments from those meals are deposited into carnivore scats and pellets. Packrats then gather these scats and pellets in their nests, and over time the nests are buried by wind-blown sand. Certain Paleozoic and Mesozoic outcrops are prime real estate for packrats and for the preservation of their middens. In BENM, the Slickrock member of the Entrada (Jurassic), Navajo Sandstone (Jurassic), and the White Rim and Cedar Mesa members of the Cutler formation (Permian) weather in a way that often creates large alcoves, caves, or overhangs where packrats like to live, where mammalian carnivores and avian predators like to roost, and where eolian deposition is rapid. These are the kinds of sites where middens accumulate lots of bone and where they are protected for thousands of years. So BENM is an eccentric mix of productive Quaternary deposits in addition to the renowned Permian through Jurassic outcrops.

There are three primary reasons that the BLM, on our—the public’s—behalf, is invested in detailed surveys of the fossil resources in BENM: protection and mitigation, public engagement through outreach, and new research. Protection of fossil resources is explicitly mandated by several laws, the Paleontological Resource Protection Act in particular. Needless to say, BLM can more effectively and efficiently protect valuable fossil sites when they are known beforehand. Illegal collection of vertebrate bone and other fossils, like petrified wood, on federal lands is a pervasive issue (n.b., it is always illegal to collect vertebrate bone and fossil eggs from public lands, but invertebrate and plant fossils can be collected for personal use and enjoyment according to certain generous regulations which can be found at https://www.blm.gov/programs/cultural-heritage-and-paleontology/paleontology/rules-for-casual-collection). Casual damage to fossils is also a non-negligible issue; for example, walking, driving, or riding over fossil-bearing outcrop can easily damage exposed specimens and tracks. Yet another aspect of protection and mitigation is that, by knowing where there are fossil localities, the BLM can anticipate and redirect future development—like new roads, campgrounds, and permitting for other uses, from stock ponds to well pads—away from fossils.

Public engagement is a major component of BLM paleontology. In the Canyon Country District, there are 7 public fossil sites, like the Mill Canyon Tracksite, Mill Canyon Bone Trail, Poison Spider Tracksite, etc. Some of these sites have been known for years, while others have only recently been discovered. For example, the Mill Canyon Tracksite was found by in 2009 by a local Moab resident, then excavated and developed into an interpretive site that opened in 2016. Yet another trackway south of Moab is now being used as a site where high school and college students can learn paleontology methods by actually cleaning and photographing tracks themselves.

In southeastern Utah, the BLM also brings paleo on public lands to the community, through visits to schools, programs for kids at the public libraries and extracurricular programs, and events like the Moab Festival of Science and National Fossil Day. In 2016, we organized several science career days for high schools in Grand and San Juan Counties, highlighting geoscience careers in rural communities. New surveys of BENM relate directly to public outreach because surveys may identify new sites that are appropriate as public interpretive sites, or for teaching. In addition, being able to describe to local communities the wealth of fossils, especially newly-discovered fossils, is a way to foster appreciation and interest in public lands that goes beyond politics: people of all ages and backgrounds are excited by fossils.

Finally, surveys reveal new research opportunities. Where localities are known but unexcavated, researchers from museums and universities are partnering with BLM to collect and study specimens (e.g. the Dystrophaeus Quarry: read more at https://www.facebook.com/Dystrophaeus). In my own research on packrat middens in BENM, I use the fossilized bone and plant material to answer questions about biodiversity conservation today. Middens provide a window into the past that allows me to quantify and qualify the ways in which the modern fauna of BENM is similar, and different, from the fauna that persisted here for the last 10,000 years. New localities—whether they were deposited millions of years ago or thousands of years ago—tell us about the history of life and help us to better anticipate our future: anticipating and planning for the future is, of course, central to land management.

To learn more:

Allison wrote a blog for the Society of Vertebrate Paleontology that goes into more detail about Quaternary fossils in BENM:

http://vertpaleo.org/Society-News/Blog/Old-Bones-SVP-s-Blog/July-2017-(1)/Packrat-Paleo-in-Bears-Ears-National-Monument.aspx

Barnosky, A. D., Hadly, E. A., Gonzalez, P., Head, J., Polly, P. D., Lawing, A. M., … & Blois, J. (2017). Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems. Science, 355(6325), eaah4787. http://science.sciencemag.org/content/355/6325/eaah4787