Date of Award

6-2011

Degree Name

Master of Science

Department

Geosciences

First Advisor

Dr. William A. Sauck

Second Advisor

Dr. Alan E. Kehew

Third Advisor

Dr. Duane R. Hampton

Access Setting

Masters Thesis-Campus Only

Abstract

The objective of this research was to delineate and map the network of gravel and sand-filled channels beneath the glacial drift of Texas Township in SW Kalamazoo County, MI. These channels are excellent local aquifers that are prized by water agencies. The delineation was done by mapping the depth to the interface between the glacial drift and the much older Mississippian Coldwater Shale, which has higher density. Tunnel valleys produce gravity anomalies on the order of -0.2 to -0.4mGal. The gravity method was used to create a Bouguer gravity anomaly map of the township. A total of 360 stations were surveyed, mostly along roads, but did include off-road profiles. Station elevations were obtained using differential GPS techniques, and the data were reduced using a standard crustal density of 2.67g/cm3. Aregional trends map from a much larger area was subtracted from the Bouguer anomaly map to produce a residual Bouguer gravity map. The residual anomaly contour map revealed a low gravity anomaly trending NE-SW and another set of anomalies trending in the N-S direction. In general, the low gravity anomalies showed a complex network of tunnel channels but for the most part, corresponded strongly with the occurrence of a linear alignment of small lakes and wetlands. A seismic survey was conducted in the axis of the valley based on access and proximity to water wells for depth-to-bedrock control.

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