Graduation Semester and Year

2011

Language

English

Document Type

Thesis

Degree Name

Master of Science in Earth and Environmental Science

Department

Earth and Environmental Sciences

First Advisor

John Wickham

Abstract

Mapping the surficial deposits of the Missouri River from Sioux City, Iowa to Mondamin, Iowa brought to light a prominent set of landforms exposed in the floodplain and which are also easily visible via aerial photography. The landforms are segments of highly sinuous channel fills that exhibit the characteristic of turning up-dip against the natural southern gradient of the river valley. These prominent channel scars, of which there are only five exposed in the study area, take on a recognizable “gooseneck” shape. The allostratigraphy for the reach of the Missouri River floodplain from Sioux City to Mondamin was mapped during the summers of 2009 and 2010. Soil samples were collected in the loops for OSL dating to determine the ages of these loops and determine any time relationship between them. The purpose of this study is to assess how they initiated, developed and evolved. The gooseneck meanders in this study developed via a combination of westward river migration owing to later valley tilt by tectonic uplift and river mechanics on the margins of braided and meandering conditions that temporarily and randomly force the Missouri River into a runaway meander pattern when meandering is locally achieved. They loops eventually succumb to neck cutoff.

Disciplines

Earth Sciences | Physical Sciences and Mathematics

Comments

Degree granted by The University of Texas at Arlington

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