Wupatki National Monument paleontological resources inventory

Henderek, Robyn; Santucci, Vincent; Rizner, Benjamin; Tweet, Justin; Wood, John

This report documents the results of a paleontological resource inventory of Wupatki National Monument (WUPA), including previously recorded paleontological resources as well as newly discovered fossil sites. This report should be read in conjunction with the geologic map produced by the National Park Service Geologic Resources Division and its partners. Wupatki National Monument, located 38 km (24 mi) north of Flagstaff, Arizona, lies on the southwestern edge of the Colorado Plateau (Figure 1). The monument was originally dedicated to protect the Citadel and Wupatki Pueblos of the Northern Sinagua culture that inhabited the area largely between 1100–1250 CE (Common Era). WUPA has since grown to preserve 14,334.83 ha (35,422.13 ac) of Lower Sonoran Desert grassland, which include over 2,400 archaeological sites. Upper Paleozoic and lower Mesozoic rock formations dominate the landscape at WUPA. Approximately 92 m (300 ft) of early Permian-age (299–272 million years ago) Kaibab Formation (map units Pkh and Pkf in Table 1) and Toroweap Formation (Pt) form the extensive Antelope Prairie in the western region of the monument (Billingsley et al. 2007). These Paleozoic units form cliffs and ledges of calcareous sandstones and cherty limestones containing abundant invertebrate fossils from the Kaibab Formation. The eastern portion of the monument is dominated by the Early–Middle Triassic-age Moenkopi Formation (251–237 million years ago) (Figure 3). From 46 to 62 m (150 to 202 ft) in thickness, the Moenkopi Formation’s alternating sandstone and siltstone units form prominent mesas and buttes to the east of the Doney Mountain Fault. The Moenkopi Formation (map units TRmhm, TRmss, and TRmw) lies unconformably on top of the Kaibab Formation and below the Chinle Formation (Billingsley et al. 2007). The Moenkopi Formation has long been known for its vertebrate ichnofossil assemblages (Peabody 1948; Klein and Lucas 2010a), and WUPA’s outcrops of the Moenkopi Formation have been extremely productive, yielding abundant trace fossil assemblages of the ichnogenera Chirotherium, Synaptichnium, and Rotodactylus, a newly discovered dicynodont track (Dicynodontipus), and tetrapod swim tracks. The Moenkopi Formation outcrops within WUPA have not produced any vertebrate body fossils to date. A significant amount of Cenozoic alluvium covers the monument. WUPA has produced a considerable number of Quaternary packrat middens, which have been used to tell the story of climate change throughout the Quaternary in the WUPA area. Packrat middens are collections of plant material and food waste from packrats (Neotoma spp.), which are cemented with the rodent’s urine. This allows for exceptional preservation of plant material, which is often suitable for radiocarbon dating, enabling precise age ranges of the material. Forty-three middens have been collected from WUPA with ages ranging from 14,330 years to less than 1,000 calibrated years before present (BP).

Wupatki National Monument paleontological resources inventory

Series