Geomorphic evidence of deformation in the northern part of the New Madrid seismic zone

Abstract

In a geomorphic evaluation of the northern portion of the New Madrid seismic zone between Hickman, Ky., and Osceola, Ark., we have identified several locations where anomalous geomorphic conditions indicate possible surface deformation. For example, the slope, course, sinuosity, and dimensions of the Mississippi River have been affected by the Lake County uplift, and Tertiary-age sediments are exposed in its channel. Also, anomalous channel behavior near Caruthersville, Mo., and Barfield, Ark., suggests that these two reaches of the Mississippi River are structurally controlled. The Black River, northeast of Pocahontas, Ark., follows a peculiar angular course that suggests fracture control, and course changes of the Black, St. Francis, and Little Rivers may be tectonically controlled. The topography of Crowleys Ridge suggests that, between Jonesboro and Castor River, it is composed of at least three structural blocks that are bounded by northeast-trending faults.