Author:
Moore Christopher R.,Brooks Mark J.,Dunbar James S.,Hemmings C. Andrew,Langworthy Kurt A.,West Allen,LeCompte Malcolm A.,Adedeji Victor,Kennett James P.,Feathers James K.
Abstract
AbstractAnomalous peak abundances of platinum and Fe-rich microspherules with high-temperature minerals have previously been demonstrated to be a chronostratigraphic marker for the lower Younger Dryas Boundary (YDB) dating to 12.8 ka. This study used Bayesian analyses to test this hypothesis in multiple sequences (units) of sandy, weakly stratified sediments at Wakulla Springs, Florida. Our investigations included platinum geochemistry, granulometry, optically stimulated luminescence (OSL) dating, and culturally dated lithics. In addition, sediments were analyzed using scanning electron microscopy and energy dispersive x-ray spectroscopy to investigate dendritic, iron-rich microspherules previously identified elsewhere in peak abundances at the onset of the Younger Dryas (YD) cool climatic episode. Our work has revealed this abundance peak in platinum and dendritic spherules in five sediment sequences at Wakulla Springs. A YDB age of ~ 12.8 ka for the platinum and spherule chronostratigraphic datum in these Wakulla Springs sequences is consistent with the archaeological data and OSL dating. This study confirms the utility of this YDB datum layer for intersequence correlation and for assessing relative ages of Paleoamerican artifacts, including those of likely Clovis, pre-Clovis, and post-Clovis age and their possible responses to environmental changes known to have occurred during the Younger Dryas cool climatic episode.
Funder
Aucilla Research Institute, Inc
Publisher
Springer Science and Business Media LLC
Reference54 articles.
1. Jones, C. B. Wakulla Springs Lodge West (formerly WA418, now part of WA329). Florida Bureau of Archaeological Research Site File Document 5152 (1971).
2. Jones, C. B. and Tesar, L. D. Wakulla Springs Lodge site (8Wa329) in Edward Ball Wakulla Springs State Park Wakulla County, Florida. Florida Master Site File Report 6602. Florida Bureau of Archaeological Research, Tallahassee, FL (2004).
3. Rasmussen, S. O. et al. A stratigraphic framework for abrupt climatic changes during the Last Glacial period based on three synchronized Greenland ice-core records: refining and extending the INTIMATE event stratigraphy. Quatern. Sci. Rev. 106, 14–28 (2014).
4. Petaev, M. et al. Large Pt anomaly in the Greenland ice core points to a cataclysm at the onset of Younger Dryas. Proc. Natl. Acad. Sci. USA 110, 12917–12920 (2013).
5. Moore, C. R. et al. Widespread platinum anomaly documented at the Younger Dryas onset in North American sedimentary sequences. Scientific Reports 7(44031), 1. https://doi.org/10.1038/srep44031 (2017).