Leading The James: The Morphological Changes Of The Missouri River And The Subservient James River

Abstract

The James River flows into the Missouri River east of Yankton, SD. The degree to which the morphological changes of the Missouri River had an impact on the course of the James River is debatable. After mapping the Mission Hill and Menominee quadrangles, surficial maps have been made showing the preserved allounits of the area. Hand augers were used to ground-truth surface features located through the use of aerial photographs, topographic maps, and to confirm features on the surficial maps made. OSL samples were taken from both quadrangles and also from Meckling and Saint Helena; the latter two were mapped during the summer of 2007. A chronology of preserved fragments of the Missouri River valley in the study area was made based on OSL dating; this will aid in building a clear sedimentological picture of the study area. The main question that has been answered is the chronology of where the James joined the Missouri throughout the Holocene and how the interaction of both rivers evolved during this time period.