CONSTRUCTION OF A GEOLOGIC MAP OF THE MIAMI UNIVERSITY NATURAL AREAS BACHELOR PRESERVE NEAR OXFORD, OHIO

This study presents the results of a geologic mapping program conducted in the Bachelor Preserve of the Miami University Natural Areas near Oxford, Ohio. The motivation for the project was to develop the primary data to generate a geologic guide for general public for the University Natural Areas recreational trail system. The study area is situated in the valley and surrounding upland areas along Harker’s Run east of the Miami University campus. The geology of the area consists of Ordovician bedrock that is overlain by Quaternary surficial deposits including Pleistocene glacial till, Pleistocene/Holocene fluvial terraces, and modern alluvium. Several geologic field methods were employed to construct the geologic map of Bachelor Preserve. Bedrock exposures in both dissected drainages and in upland exposures were identified by detailed field mapping. Mapping of the Quaternary was conducted using QGIS software that utilized a high-resolution, LiDAR-derived, digital elevation model of the study area as a topographic base. A combination of a 1 ft contour interval and variable hillshade illuminations aided in the identification of dissected terraces. A local relative elevation model calibrated to Harker’s Run was created to correlate terraces across topography. The existence and extent of surficial geomorphological components identified in the GIS mapping were verified in the field. In addition, a portable XRF was used to establish relative ages for the mapped terraces.

Mapping results included the identification and delineation of Ordovician outcrops, multiple fluvial terraces, active alluvial fans, and the modern Harker’s Run floodplain and channels. Collectively, project results provide a detailed map that will serve as the basis for a trail guide that will highlight the geological history of the Bachelor Preserve.