Age and Correlation of Fossiliferous Late Paleocene–Early Eocene Strata of the

The Asian continent preserves a rich and diverse record of Paleogene mammal faunas and their evolution through time. The sequence of faunal succession is of key importance to our understanding of the origin and diversification of modern mammal groups, as phylogenetic data suggest that many major modern clades may be rooted in Asia. By calibrating the Asian fauna sequence within a chronostratigraphic framework, we can begin to compare patterns of succession on a global scale and constrain models for the origination and dispersal of modern mammal groups in the early Paleogene. The Erlian Basin of Inner Mongolia preserves Early Paleogene strata and mammal fossils assignable to the Gashatan, Bumbanian, and Irdin Manhan Asian Land Mammal Ages (AL-MAs). We measured stratigraphic sections and analyzed the stable isotope composition of paleosol carbonates and paleomagnetic directions of rocks at three localities in the Erlian Basin. The data document patterns in lithology, carbon isotope composition, and magnetic polarity that are consistent at all three localities and allow us to present two constrained hypotheses for the correlation of the local stratigraphic sections. Within the resulting composit