| Abstract: | Abstract This study of longitudinal stream profiles of rivers of the Midcontinent (rivers tributary to the Mississippi) and Atlantic and East Gulf Slopes has revealed five types of longitudinal profiles: (1) Overall concave-upward profiles with or without long constant slope segments; (2) convex upward, for example, the Missouri River has a profile that has a constant slope for its lower 560 miles and then is convex upward with constant slope segments to a point beyond the Yellowstone River junction; (3) concave-upward irregular, ungraded, low-gradient profiles (Ohio and Tennessee Rivers); (4) irregular unsegmented and steep profiles, such as shown by the Delaware and Savannah-Tugaloo Rivers; and (5) irregular ungraded, steep-gradient profiles that are concave-upward in the upstream reaches and downstream convex-upward, for example, on most of the Atlantic Slope and East Gulf Slope Rivers above the Fall Line. Constant slope profiles occur where the last type of rivers flow across relatively weak Coastal Plain sediments and also inland on the Coosa and Oostanaula-Conasauga Rivers. The profile characteristics of the Atlantic and East Gulf streams lend support to the hypothesis of multiple erosion cycles in the Appalachians. |
