Tectonic Modifications Shape Surface Environment and Landscape

Major tectonic features within the North American midcontinent. The red and purple stars mark the locations of the Illinois-Kentucky Fluorspar District, with igneous intrusions at around 270 million years ago (Ma), and the Lake Ellen (Michigan) kimberlites with an age of 186-206 Ma. The inset diagram shows the geometry and Carboniferous faulting along the Ste. Genevieve Fault Zone. IB, MB, and WB mark the Illinois, Michigan, and Williston basins, respectively. MCR, RR, and LSDB indicate Midcontinent Rift, Reelfoot Rift, and La Salle Deformation Belt. WD, OD, and ND indicate the Wisconsin Dome, Ozark Dome, and Nashville Dome, respectively. Credit: Yang et al. [2026], Figure 2a