Tag archives for Ozark Plateau

Gasconade River drainage basin area landform origins, Missouri, USA, Overview Essay

A geomorphic history based on topographic map evidence

The Gasconade River is a northeast and north-northeast oriented Missouri River tributary and flows from near Seymour, Missouri to join the east-oriented Missouri River, near Gasconade, Missouri. Major Gasconade River tributaries include north-oriented the Osage Fork, Roubidoux Creek, and the Big Piney River. This Gasconade River knol collection provides a summary of knols describing landform origins for all drainage divides surrounding the Gasconade River drainage basin. Knols being summarized are based entirely on illustrated topographic map evidence and interpret landform origins from a previously unexplored perspective of a deep glacial erosion and a thick ice sheet that melted fast paradigm. Topographic map evidence shown and discussed in these knols documents how the deep Gasconade River valley and its north-oriented tributary valleys were eroded by systematic reversals of an immense south-oriented flood, which was derived from a rapidly melting North American ice sheet. Prior to headward erosion of the deep Missouri River valley flood waters flowed south across what is now the Gasconade River drainage basin to what was then the newly eroded southeast-oriented White River valley and what were then actively eroding south-oriented White River tributary valleys. Headward erosion of the deep east-oriented Missouri River valley beheaded the south-oriented flood flow routes in sequence from east to west. Flood waters on north ends of beheaded flood flow routes reversed flow direction to erode deep north-oriented valleys. The actively eroding north-oriented valleys captured significant south-oriented flood flow from west of the actively eroding Missouri River valley head. The captured flood water moved in southeast, east, and northeast directions and caused the north-oriented valleys, such as the Gasconade River valley, to erode headward toward the southwest and to also behead south-oriented flood flow routes in sequence from east to west. The Gasconade River valley was able to erode headward for a significant distance faster than the actively eroding Missouri River valley and its Osage River tributary valley were able to behead south-oriented flood flow routes supplying flood waters to the actively eroding Gasconade River valley. Headward erosion of the deep Osage River valley from the actively eroding Missouri River valley finally beheaded and captured all flood flow routes to the what had been the actively eroding Gasconade River valley. Knols in this collection illustrate and discuss how topographic map evidence including positions and orientations of present day valleys, the nature of Gasconade River valley and tributary valley meanders, and through valleys crossing present day drainage divides, all provide evidence supporting this flood origin interpretation.