Stratigraphy and paleontology of Trapped Rock Draw mastodont site, Zuni, New Mexico
Paul G. Drakos, Spencer G. Lucas, Gary S. Morgan, and Steven L. Reneau


A mastodont mandible was found within a 12.4-m-thick late Quaternary section exposed in an arroyo wall along Trapped Rock Draw, 2 km south of Zuni, NM. The Pleistocene stratigraphic section that contains the mandible suggests deposition in a low energy fluvial environment with small channels. The Pleistocene stratigraphic section is interpreted to represent a shallow, sandy, aggrading stream system. Stratigraphic relationships support the inference that the mastodont is a late Pleistocene-age fossil of Mammut americanum. M. americanum is rare in New Mexico and the southwestern United States, especially when compared to the numerous records of mammoths from this region. The Trapped Rock Draw mandible is the sixth record of M. americanum from New Mexico, and the first record from the Colorado Plateau in the northwestern part of the state. Invertebrate faunal analysis of samples collected from the stratigraphic section containing the mandible suggests that paleoenvironmental conditions at the time of the Trapped Rock Draw mastodont were characterized by complex ecosystems and a somewhat cooler and wetter climate than at present, with localized marshy conditions. Absolute age constraints are not currently available for the mastodont specimen, but charcoal samples collected from strata that overlie and underlie the mandible could provide an excellent temporal framework for the Trapped Rock Draw mastodont and the associated late Quaternary stratigraphic section.


  1. Drakos, Paul G.; Lucas, Spencer G.; Morgan, Gary S.; Reneau, Steven L., 2003, Stratigraphy and paleontology of Trapped Rock Draw mastodont site, Zuni, New Mexico, in: Geology of the Zuni Plateau, Lucas, Spencer G.; Semken, Steven C.; Berglof, William R.; Ulmer-Scholle, Dana S., New Mexico Geological Society, Guidebook, 54th Field Conference, pp. 419-424.

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