AN AMAZON-SCALE DRAINAGE SYSTEM IN THE EARLY PENNSYLVANIAN OF CENTRALNORTH-AMERICA

This study compares Morrowan conglomeratic sandstones from three basin s in the central North American craton: Central Appalachian Basin (eas tern Kentucky), Eastern Interior Basin (Illinois, Indiana, western Ken tucky, and lateral extensions in Arkansas), and Hugoton Embayment (Kan sas and Colorado) to develop realistic analogues for Morrowan fluvial systems and to compare the relative effects of tectonic subsidence, eu stacy, and paleoclimate on sedimentation. Based on paleogeographic rec onstruction, the paleodrainage for the Central Appalachian Basin is es timated to have ranged from 1,337,100 km(2) to 2,854,300 km(2), and fo r the Eastern Interior Basin from 1,568,600 km(2) to 4,011,500 km(2). These sizes are comparable in scale to the modern Amazon River drainag e area. Paleodrainage for the Hugoton Embayment was considerably small er, estimated at 128,600 km(2) to 282,900 km(2). Comparing the varying effects of tectonic, eustatic, and paleoclimatic controls, the Centra l Appalachian Basin and Hugoton Embayment were particularly affected b y ongoing regional tectonism, whereas the Eastern Interior Basin was a ffected to a much lesser extent. Eustatic changes influenced the devel opment of sandstones, particularly within the Hugoton Embayment and th e Eastern Interior Basin: Effects of climate were much more difficult to estimate, but the low-latitude position of the eastern basins had s ignificant effects on the maturity of the sandstones and on the sizes of the fluvial systems. Degree of seasonality affected styles of fluvi al sedimentation and paleosol development.