Pleistocene geology and classic type sections along the Missouri River valley in western Iowa

This field guide describes four exposures of glacigenic sediment along the Missouri River bluffs east of Omaha, Nebraska. Field trip stops include Loveland, Iowa, which is the type section of the Loveland Silt and Pisgah Formation (Illinoian and Early Wisconsinan loess) and Crescent Quarry, which exposes the type Nebraskan till. Additionally we will examine core samples of the Kennard Formation, a new stratigraphic unit consisting of multiple pre-Illinoian loesses. We also present recent results on the pre-Illinoian till stratigraphy in the Missouri River valley region. A variety of evidence indicates that the present location of the Missouri River valley originated sometime between deposition of the youngest (pre-Illinoian) till and the (Illinoian) Loveland Silt. The spatial distribution of the youngest pre-Illinoian till further suggests that this reach of the Missouri River (along the Iowa-Nebraska border) was established as an ice-marginal stream along the western terminus of the last pre-Illinoian glaciation.