Mojave National Preserve: Paleontological resource inventory (sensitive version)
Authors: Johnson Emily , Andeskie Sofia , Tweet Justin , Santucci Vincent 
Published: June 2023

Mojave National Preserve (MOJA) in the Mojave Desert of southern California hosts an extensive geologic record, with units ranging in age from the Paleoproterozoic (2.5 to 1.7 billion years ago) to the Quaternary (present day). MOJA topography is dominated by numerous mountain ranges hosting extensive geological exposures divided by expansive valleys, dunes, and a low elevation dry salt lake. Some geological units are fossil-bearing, both within the preserve and in adjacent lands outside the boundaries of the preserve. The fossils preserved within MOJA span from the Proterozoic Eon (uncertain maximum age of fossiliferous rocks, but at least approximately 550 million years ago) to the Holocene Epoch (beginning 11,700 years ago). Abundant and diverse marine fossils are preserved in units dated from the late Proterozoic through most of the Cambrian, as well as from the Devonian through the early Permian. More recent volcanic tuff and unconsolidated sedimentary deposits in valleys preserve Cenozoic flora and fauna. Geologic surveys documented paleontological resources within the modern (2023) boundaries of MOJA as early as 1914, but fossils were rarely the focus of detailed study, and no comprehensive inventory was compiled. John Hazzard was the first geologist to devote significant attention to the study of paleontology within MOJA. Throughout the 1930s and 1940s, Hazzard and collaborators identified Paleozoic assemblages within the Kelso and Providence Mountains. Between the 1950s to 1980s, several dissertations and theses described the geology of various areas within MOJA, in which the authors provided limited paleontological descriptions and fossil locality information. Jack Mount conducted extensive paleontological research in the Cambrian sections of the Providence Mountains in the 1970s and 1980s, focusing on olenellid trilobites in the Latham Shale. As early as the 1960s, rockhounds collecting opalite and petrified wood at Hackberry Wash discovered fossilized plant material and vertebrate bones and notified paleontologists at San Bernardino County Museum (SBCM). This resulted in one of the only paleontological excavations in what is now MOJA, with collections of Miocene vertebrate fauna including camelid and early rhino material. More recently, James Hagadorn reported the late-surviving Ediacaran organism Swartpuntia in an assemblage from the Wood Canyon Formation of the Kelso Mountains in 2000. From October 2021 to January 2022, a field inventory was conducted to determine the scope and distribution (both temporal and geospatial) of paleontological resources at MOJA. An additional week of field work was conducted in December 2022. A total of thirteen localities were documented and field-checked throughout the preserve. These localities resulted from field checks of previously reported fossil sites, as well as new discoveries based on literature searches and information provided by MOJA staff. The findings of this report constitute a baseline of paleontology resource data for MOJA, and reflect the current understanding of the scope, significance, and distribution of MOJA’s fossil record. This report provides a foundation for the management and protection of paleontological resources within MOJA and supports future education, interpretation, and research.