Nemaha Ridge

Structures of Kansas showing the Nemaha Uplift/Ridge

The Nemaha Ridge (also called the Nemaha Uplift) is located in the Central United States. It is a buried structural zone associated with a granite high in the Pre-Cambrian basement that extends from approximately Omaha, Nebraska to Oklahoma City, Oklahoma. The ridge is associated with the seismically active Humboldt Fault zone. It is also associated with the Proterozoic Midcontinent Rift System, which extends into northern Kansas about fifty miles west of the Nemaha.^[1]

Along the Nemaha Ridge is a series of faults referred to as the "Nemaha Fault Zone".^[1] The long term uplift along the ridge has been attributed to isostatic uplift due to the anomalously thick crust adjacent to the Midcontinent Rift.^[2]

References

1. Kansas Geological Survey, Current Research in Earth Sciences, Bulletin 250, part 1 "Review of the Nemaha Ridge: A New Look at an Old Structure"
2. Gao, Stephen S., et al., Old Rifts Never Die: Crustal Thickening Across the Midcontinent Rift and Its Possible Role in Post-Rifting Tectonics, Structure and Tectonics of the Midcontinent, North America, GSA 2002 Denver Annual Meeting