Date of Award


Degree Name

Master of Science


Geological and Environmental Sciences



First Advisor

Dr. William A. Smith

Second Advisor

Dr. Estella Atekwana

Third Advisor

Dr. William B. Harrison III

Access Setting

Masters Thesis-Open Access


A detailed gravity study consisting of 945 measurements was carried out in Branch County, Michigan. The objectives of this study are to determine if: (a) structural trends interpreted from regional gravity data in southwestern Michigan are also observed in a more detailed survey in Branch County and (b) any relationship exists between observed geophysical anomalies, geological structures and overlying basin sediments.

The resulting gravity map indicates that NW-SE, NE-SW, and N-S trends are more clearly identified comprising several elliptical highs and lows. Variations in the isopachs of some of the overlying Phanerozoic formations area are also coincident with gravity anomalies. The implication of this is that basement fault reactivation had occurred, evidently ceasing during the Middle Ordovician. Two-dimensional modeling along profiles in Branch County and southwest Michigan, correlated with drill-hole data, suggest that the anomaly pattern is probably due to lateral changes in basement petrology influenced by local mafic intrusions within the basement

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Geology Commons