Late Quaternary environments of the Waco Mammoth site, Texas USA. Issue 3 (November 2015)

• Record Type: Journal Article
• Authors: Nordt, Lee; Bongino, John; Forman, Steven; Esker, Don; Benedict, Anita
• Is Part Of: Quaternary research. Volume 84:Issue 3(2015)
• Page Start: 423
• Page End: 438
• Publication Date: 2015-11
• Subjects: Mammoth, -- Catastrophic, -- Brazos River, -- Pleistocene, -- Alluvium; Geology, Stratigraphic -- Quaternary -- Periodicals; Glacial epoch -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; Époque glaciaire -- Périodiques; Geology, Stratigraphic; Glacial epoch; Quaternary Geologic Period; Electronic journals; Periodicals; 551.79
• DOI: 10.1016/j.yqres.2015.10.003
• Languages: English
• ISSNs: 0033-5894

Abstract

Abstract : The Waco Mammoth Site (WMS) in central Texas contains the remains of the largest mammoth herd ( Mammuthus columbi ) in North America that died in a single catastrophic event. Most mammoths at the site died on a gravel bar of the ancient Bosque River adjacent to a collapsing tributary wall. However, the timing and cause of death of the 26 mammoths documented to date are controversial. The objectives of this research are to: describe and interpret the alluvial stratigraphy and infer the cause of death, employ optically stimulated luminescence (OSL) dating to determine the timing of death, and analyze stable C isotopes of pedogenic carbonate to infer local plant communities, dietary habits, and summer temperatures. Dating of quartz from seven sediment samples by OSL places the death event to a weighted mean of 66.8 ± 5.0 ka. The site is coeval with Marine Oxygen Isotope Stage 4, consistent with our reconstructed mean July temperatures ~ 4°C cooler than today based on a buried soil isotopic transfer function. Our buried soil isotopic interpretation of a dominance of C3 plants is contrary to previous studies of mammoth tooth enamel at the site suggesting a dietary preference for warm season grasses (C4 ).