Extension of the Mid-Continent Rift System into the Southern Mid-Continent Region: Possible Implications for Exploration and Natural Hazards

Abstract

The Mid-Continent rift system is a prominent, 1.1 Ga age feature that extends to both the SE and SW from the Great Lakes region. The southwestern arm is often thought of as extending only to Kansas. However, there are gravity, magnetic, seismic and drilling results that suggest this feature may extend across Oklahoma and even into West Texas. In Oklahoma and southern Kansas, simple residual gravity maps reveal a clear NNE trend of gravity highs that generally correlate with the Nemaha uplift. These anomalies are too large to be due to just the modest basement relief across this structure. Thus, deeper linear features that are dense are required to explain these anomalies. One simple explanation is that the Mid-Continent rift system extends across central Oklahoma and is cut by the younger Arbuckle-Wichita uplift. The magnetic anomalies across the region are very complex, but there are linear trends in places that correlate with the linear gravity anomalies. There is also a general correlation the geophysical anomalies with earthquake activity in central Oklahoma. Thus, we suggest that the Mid-Continent rift system extends across Oklahoma and widens much like the East African rift extends through Kenya and widens in Tanzania. These features could have been reactivated in the Pennsylvanian to produce the Nemaha uplift, and some may be reactivated today.

AAPG Datapages/Search and Discovery Article #90221 © 2015 Mid-Continent Section, Tulsa, Oklahoma, October 4-6, 2015