Abstract

A correct paleogeographic interpretation of the North American Early Mississippian depends on a proper understanding of the transition from an expansive carbonate-dominated depositional system that surrounded the Transcontinental arch into a system composed largely of clastics that was derived from the continental margins. Biostratigraphic works at this transition during the past 20 years support its interpretation as a carbonate shelf-edge. Waulsortian-type mud mounds developed along this shelf-edge which was smothered in Late Mississippian time by a cratonward prograding clastic wedge. The shelf-edge interpretation is in opposition to other suggested models including (1) carbonate-to-clastic facies transition, and (2) tectonic uplift and erosion of the carbonates followed by deposition of the clastics. It is now possible to relate seemingly disparate occurrences of the Early Mississippian Waulsortian-type mounds in North America.