Deep Erosion by Continental Ice Sheets: A Northern Missouri River Drainage Basin Perspective: North America

Abstract

While accepting some erosion by continental ice sheets most geologists reject a previously proposed deep erosion by continental ice sheets hypothesis, yet common sense logic suggests continental ice sheets should have eroded much more than they are usually given credit for. Such situations arise in scientific communities when an accepted paradigm cannot adequately explain significant observable evidence. A new and fundamentally different paradigm, constructed from detailed topographic map evidence, illustrates how deep erosion (and crustal warping) by at least one continental ice sheet explains previously unexplained northern Missouri River drainage basin erosional landform origins. The new paradigm requires at least one North American continental ice sheet to have created (by deep erosion and by ice sheet related crustal warping) a deep “hole” in which the ice sheet was located. Late during that ice sheet’s melt history north- and northeast-oriented valleys eroded headward from that deep “hole’s” southern end to capture immense southeast-oriented ice-marginal melt-water floods and to create what are today north- and northeast-oriented Missouri River headwaters and tributary drainage routes. While successfully explaining numerous previously unexplained erosional landforms the new paradigm challenges a number of commonly accepted middle and late Cenozoic geologic and glacial history interpretations.