Date of Award
Master of Science
Geological and Environmental Sciences
Dr. Christopher J. Schmidt
Dr. William A. Sauck
Dr. W. Thomas Straw
Masters Thesis-Open Access
Gravity geophysics along with well data were used to delineate and map the locations of buried river valleys in Calhoun County, Michigan. The valleys are filled with thick sequences of glacial fluvial deposits which can serve as important aquifers.
One hundred and sixty-four gravimeter observations were made at approximately one-quarter mile intervals in a 35 square mile area. Four short-interval profiles were also established perpendicular to suspected valleys. A three-dimensional trend surface polynomial was fitted to the total Bouguer anomaly to approximate the regional effect of gravity. By comparing the observed residual gravity to theoretically derived anomalies, models were developed which approximated the shape of the bedrock topography.
Two main valleys were mapped with the use of gravity and well log data. The topographic map of the bedrock surface indicates several tributaries and two possible saddles between the two valleys. Valley flow elevations indicate that locally, preglacial drainage was toward the southwest.
Farnsworth, James W., "Relationship of Gravity Anomalies to a Drift Filled Bedrock Valley System in Calhoun County Michigan" (1980). Master's Theses. 1870.