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Previous studies documented dentognathic fossils that are morphologically intermediate betweenÌýAustralopithecus anamensisÌýandAustralopithecus afarensisÌýand some that are attributed toÌýAustralopithecus afarensis. Additional dentognathic remains from the study area were assigned to the newly identified speciesÌýAustralopithecus deyiremeda. These fossil hominin taxa were recovered from volcanic and sedimentary strata containing tuffs ranging in age from more than 3.77 million years ago (Ma) to less than 3.469ÌýMa. One of the tuffs was correlated based on geochemistry, feldspar mineralogy, and age to the Lokochot Tuff of the Omo-Turkana Basin of southern Ethiopia and Kenya. Variations in major and minor element abundances in volcanic glass demarcate ten geochemically distinct tuffs and tuff sequences, including three that are geochemically similar to widespread regional tuffs, specifically the Lomogol, Lokochot, and β− Tulu Bor/Sidi Hakoma tuffs. A newÌý⁴⁰Ar/³⁹Ar age for the Waki Tuff, which is geochemically similar to the Lomogol Tuff, is 3.664Ìý±Ìý0.016ÌýMa. Other tuffs in the Waki-Mille area are geochemically dissimilar to regional tuffs documented to date. Identification of tuffs based on character, stratigraphic position, and geochemistry refines local stratigraphic correlations and delineates the geographic distributions of precisely dated fossiliferous levels within the Waki-Mille area.

Tephrostratigraphy of the Waki-Mille area of the Woranso-Mille paleoanthropological research project, Afar, Ethiopia

Beverly Z. Saylor, Joshua Angelini, Alan Deino, Mulugeta Alene,ÌýJohn H. Fournelle, Yohannes Haile-Selassie

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