GSA Connects 2022 meeting in Denver, Colorado

Paper No. 165-11
Presentation Time: 9:00 AM-1:00 PM

HUMAN IMPACTS ON EROSION RATES IN STARVED ROCK STATE PARK, ILLINOIS


THIELBAR, Savannah, Department of Geography, Geology and the Environment, Illinois State University, Campus Box 4400, Normal, IL 61790-4400 and TRANEL, Lisa M., Department of Geography-Geology, Illinois State University, 100 N. University Street, Normal, IL 61790

State and national parks are some of the most visited wildlife areas within the United States, allowing the local geology to become more susceptible to human-induced change. As more people visit these parks throughout the year, we see major impacts on the interactions between biological and geological processes. This study will determine if human activity and rock carvings influence erosion rates within Starved Rock State Park and will provide new perspective on our compounding anthropogenic influence on Earth. Through natural stream and artificial human erosion, the base of the bedrock slope is potentially changing at a much faster rate than the upper portion of the outcrop. By monitoring the fragile sandstone cliffs that preserve these human-created carvings, we collect specific erosion data on four different canyons within the park. Canyon wall data are collected and monitored using an Empire contour gage, a rebound Schmidt hammer, and an iPhone 13 LiDAR camera and app program to determine seasonal variations in erosion throughout the park as well as the influence of surficial case hardening on the outcrops. We hypothesize that carving can enhance short-term bedrock erosion rates within these areas. The contour and Schmidt hammer data collected suggest that the bedrock of the area is affected on a small, millimeter scale within a short period of time. We compared data collected from the carvings to bedrock that is naturally eroding without human influence to understand localized changes to bedrock surfaces and consider connections to long-term cosmogenic nuclide data. Preliminary analysis of previously collected thin sections indicate that some locations have stronger rock surfaces driven by differences in cement concentrations from the surface to the interior of the rock outcrops. Future research identifying the magnitude of this impact over a longer period, as well as the impact on other lithologies, can prove to be valuable in increase education and awareness at other state or national parks.