Lithologic Controls on Bedrock Channel Morphology in the Buffalo River Basin

The longevity of high relief terrains in passive margin systems remains an explained phenomenon in geomorphology. Current landscape evolution models assume an equilibrium state between rock uplift rates and erosion rates. However, analysis of chi gradients of bedrock channels across several lithologies in the Buffalo River Basin reveals disequilibrium in the basin controlled by the presence of a thick interval of Pennsylvanian sandstone that caps many of the plateaus in the basin. Headwater channels beneath the caprock tend to have higher chi gradient values in all lithologies than headwater channels in basins where the sandstone caprock is absent. High chi gradients in the Boone Formation, a Mississipian age limestone, typically correspond to knickpoints arrested at the upper contact. Field and laboratory analysis suggest that limestone dissolution may be an important mechanism for knickpoint initiation in the Boone Formation