Stratigraphy and Pollen Analysis of Yarmouthian Interglacial Deposits in Southeastern Indiana

Abstract

Additional stratigraphic study and pollen analysis of organic units of pre-Illinoian drift in the Handley and Townsend Farms Pleistocene sections in southeastern Indiana have provided new data that change previous interpretations and add details to the history recorded in these sections. Of particular importance is the discovery in the Handley Farm section of pollen of deciduous trees in lake clays beneath Yarmouthian colluvium, indicating that the lake clay unit is also Yarmouthian. The pollen diagram spans a substantial part of Yarmouthian interglacial time, with evidence of early temperate and late temperate vegetational phases. It is the only modern pollen record in North America for this interglacial age. The pollen sequence is characterized by extraordinarily high percentages of Ostrya-Carpinus pollen, along with Quercus, Pinus, and Corylus at the beginning of the record; this is followed by higher proportions of Fagus, Carya, and Ulmus pollen. The sequence, while distinctive from other North American pollen records, bears recognizable similarities to Sangamonian interglacial and postglacial pollen diagrams in the southern Great Lakes region.