GEOLOGY OF THE INTERMOUNTAIN WEST an open-access journal of the Utah Geological Association ISSN 2380-7601 Volume 7 2020 PALEONTOLOGY OF BEARS EARS NATIONAL MONUMENT (UTAH, USA)— HISTORY OF EXPLORATION, STUDY, AND DESIGNATION Robert J. Gay, Adam K. Huttenlocker, Randall B. Irmis, M. Allison Stegner, and Jessica Uglesich © 2020 Utah Geological Association. All rights reserved. For permission to copy and distribute, see the following page or visit the UGA website at www.utahgeology.org for information. Email inquiries to [email protected]. GEOLOGY OF THE INTERMOUNTAIN WEST an open-access journal of the Utah Geological Association ISSN 2380-7601 Volume 7 2020 Editors UGA Board Douglas A. Sprinkel Thomas C. 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If you would like to participate please contact the current are not noted as copyrighted, provided the original president or committee member corresponding with the area in which you would author and source are credited. like to volunteer. Utah Geological Association formed in 1970 from a merger of the Utah Geological Society, founded in 1946, and the Intermountain Association of Geologists, founded in 1949. Affiliated with the American Association of Petroleum Geologists. i GEOLOGY OF THE INTERMOUNTAIN WEST an open-access journal of the Utah Geological Association Volume 7 2020 Paleontology of Bears Ears National Monument (Utah, USA)—History of Exploration, Study, and Designation Robert J. Gay1, Adam K. Huttenlocker2, Randall B. Irmis3, M. Allison Stegner4, and Jessica Uglesich5 1Colorado Canyons Association, 543 Main St. #4, Grand Junction, CO 81501; [email protected]; [email protected] 2Department of Integrative Anatomical Sciences, University of Southern California, Los Angeles, CA 90007; [email protected] 3Natural History Museum of Utah and Department of Geology & Geophysics, University of Utah, Salt Lake City, UT 84108-1214; irmis@ umnh.utah.edu 4Department of Biology and Jasper Ridge Biological Preserve, Stanford University, Stanford, CA 94305-5020; [email protected] 5Friends of Cedar Mesa+, Bluff, UT 84512 and University of Texas at San Antonio, Department of Geosciences+, San Antonio, TX 78249; [email protected]; +Former affiliation ABSTRACT Bears Ears National Monument (BENM) is a new landscape-scale national monument in southeastern Utah, jointly administered by the Bureau of Land Management and the U.S. Forest Service as part of the National Conservation Lands system. As initially designated in 2016, BENM encompassed 1.3 million acres of land with exceptionally fossiliferous rock units. Subsequently, in December 2017, presidential action reduced BENM to two smaller management units (Indian Creek and Shash Jáá). Although the pa- leontological resources of BENM are extensive and abundant, they have historically been under-studied. Herein we summarize prior paleontological work within the original BENM boundaries to provide a more comprehensive picture of the known paleontological resources, which are used to support paleontological resource protection. The fossil-bearing units in BENM comprise a nearly continuous depositional record from aproximately the Middle Pennsylvanian Period (about 310 Ma) through the middle of the Cretaceous Period (about 115 Ma). Pleistocene and Holocene deposits are known from unconsolidated fluvial terraces and cave deposits. The fossil record from BENM provides unique insights into several important pale- ontological intervals of time including the Carboniferous-Permian icehouse-greenhouse transition and evolution of fully terrestrial tetrapods, the rise of the dinosaurs following the end-Triassic mass extinction, and the response of ecosystems in dry climates to sudden temperature increases at the end of the last glacial maximum. INTRODUCTION by the 1859 Macomb Expedition (Newberry, 1876), but interest and exploration among local native communi- Southeastern Utah has a diverse and significant ties predates the late 19th century and extends to An- paleontological record of the late Paleozoic through cestral Puebloan communities (Mayor 2005; Smith and mid-Mesozoic eras. The first published paleontological others, 2016; W. Greyeyes, Navajo Nation, verbal com- work in the region dates to the 1870s, based on fieldwork munication, 2017). In a remarkable union of archaeol- Citation for this article. Gay, R.J., Huttenlocker, A.K., Irmis, R.B., Stegner, M.A., and Uglesich, J., 2020, Paleontology of Bears Ears National Monument (Utah, USA)—history of exploration, study, and designation: Geology of the Intermountain West, v. 7, p. 205–241, https://doi.org/10.31711/giw.v7.pp205-241. © 2020 Utah Geological Association. All rights reserved. For permission to use, copy, or distribute see the preceeding page or the UGA website, www.utahgeology.org, for information. Email inquiries to [email protected]. 205 Paleontology of Bears Ears National Monument (Utah, USA)—History of Exploration, Study, and Designation Gay, R.J., Huttenlocker, A.K., Irmis, R.B., Stegner, M.A., and Uglesich, J. ogy and paleontology, there is evidence in Bears Ears INSTITUTIONAL ABBREVIATIONS National Monument that Ancestral Puebloans inten- tionally utilizing fossils in pueblo construction (Smith BENM, Bears Ears National Monument; BLM, and others, 2016). Today, paleontological research in Bureau of Land Management; GSENM, Grand Stair- the region is advancing our understanding of critical case-Escalante National Monument; SGDDS, St. George evolutionary events, major extinctions, biogeography Dinosaur Discovery Site at Johnson Farm; UCMP, Uni- and ecology of extinct and extant organisms, and the versity of California Museum of Paleontology; UMNH, morphologic and taxonomic diversity of life on Earth Natural History Museum of Utah; USGS, United States through time. Specific high-priority research objec- Geological Survey; USC, University of Southern Cali- tives in BENM include deepening our understanding of fornia. the evolution of fully terrestrial ecosystems during the icehouse-hothouse transition preserved in the Upper HISTORY OF MONUMENT DESIGNATION Pennsylvanian-Lower Permian Cutler Group, generat- The idea of federal protection for the region now ing a comprehensive unified stratigraphy and invento- known as BENM was conceived as early as 1936. At that ry across the Triassic Chinle Formation, and invento- time, a proposed “Escalante National Monument” in- ry and study of the Quaternary fossil resources of the cluded what is now Grand Staircase-Escalante Nation- monument to elucidate post-glacial diversity change. al Monument, Glen Canyon National Recreation Area, Illegal excavations and collections in this region Natural Bridges National Monument, and the majori- have been problematic for at least the past several