Cross Sections Depicting Unconsolidated Sediment Stratigraphy of Northern Indiana Map and cross sections

Abstract

Northern Indiana hosts the largest diversity of glacial sediments in the state. Five cross sections are presented here to illustrate the stratigraphic relationships between them. The sections were drawn to include sediments derived from the advance of the three lobes of the Laurentide Ice Sheet that can be recognized in Indiana: the Lake Michigan Lobe, the Huron-Erie Lobe, and the Saginaw Lobe (Plate 1). These cross sections form the basis for understanding the glacial geology and stratigraphy of the region, and for identifying and characterizing the aquifer geometry and lithology needed to properly manage the valuable groundwater resources of this portion of the state.

Unconsolidated sediments have been classified according to stratigraphic parameters, either as part of formal stratigraphic units (for example, Wayne, 1963), or informally as suggested in recent publications (for example, Loope and Antinao, 2025) and modified as needed. When limited data are available, roughly defined units based on grain-size sorting are presented. Areas in the cross sections without data coverage are highlighted to guide future studies.

The bedrock topographic profiles depicted on the cross sections were defined using additional data, including published data sets (Naylor and others, 2016), water, oil and gas well information, and newer geophysical data. The topographic surface profile was extracted from a downsampled LIDAR data set for the entire state. Gamma-ray geophysical logs are displayed for select boreholes in the cross sections.