Earth Sciences Commons^™

From Hillslopes To Canyons, Studies Of Erosion At Differing Time And Spatial Scales Within The Colorado River Drainage, Christopher Tressler

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis includes two different studies in an attempt to investigate and better understand the key characteristics of landscape evolution. In the first study, the rate of surface particle creep was investigated through the use of Terrestrial lidar at an archaeological site in Grand Canyon National Park. The second study developed ways to quantify metrics of the Colorado River drainage and reports the role of bedrock strength in the irregular profile of the trunk Colorado River drainage.

Archaeological sites along the Colorado River corridor in Grand Canyon National Park are eroding due to a variety of surficial processes. The nature …

Quaternary Evolution Of The Colorado River At Lees Ferry, Arizona, William Scott Cragun

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A well-exposed suite of Colorado River fill terraces preserved at Lees Ferry records the oscillating history of this major river superimposed on its overall downcutting of the Colorado Plateau. Detailed mapping, sedimentology, cross-sectional surveys, and the use of two geochronometers have been used in order to establish a detailed chronostratigraphy for the area. Eight distinct deposits have been identified along the Colorado River (Ml -M7, and S3), and four deposits have been identified along the Paria River (Pl -P4).

Geochronology of six of these deposits using optically stimulated luminescence and cosmogenic ¹⁰Be exposure techniques indicates a long-term average bedrock …

From The Rim To The River: The Geomorphology Of Debris Flows In The Green River Canyons Of Dinosaur National Monument, Colorado And Utah, Isaac J. Larsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Green River canyons of the eastern Uinta Mountains have experienced a 5-year period of high debris flow activity. Catchment factors were studied in watersheds and on debris fans with recent debris flows, leading to the development of a conceptual framework of the hillslope and debris flow processes that deliver sediment to the Green River. Two recent fan deposits were monitored to determine the magnitude and processes of reworking that occur during mainstem floods of varying magnitude.

The dominant debris flow initiation mechanism, termed the firehose effect, occurs when overland flow generated on bedrock slopes cascades down steep cliffs and …

Debris-Flow Activity In Canyon Of Lodore, Colorado: Implications For Debris-Fan Formation And Evolution, Jennifer A. Martin

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Large-scale characteristics of Ladore Canyon debris fans are dependent upon the bedrock and lithology of the mainstem and tributary canyons. The largest fans occur in the widest section of the mainstem canyon, which typically correlates with the location of large faults. The steepest fans are found at the mouths of tributaries where cliffs are formed by resistant lithologies. Smaller-scale fan characteristics are dependent upon the magnitude and frequency of events from the respective drainage basin, which is controlled primarily by climate. Three distinct deposit ages (oldest, intermediate, youngest) were distinguished on individual fans and were tentatively correlated throughout the canyon …

Groundwater And Surface-Water Interactions Along Lower Medano Creek, Great Sand Dunes National Monument, Colorado, Gregg L. Hadlock

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objectives of this investigation are as follows: 1) review the existing hydrogeologic data for the San Luis Valley, the Great Sand Dunes Monument, and Medano Creek; 2) review the surface-water data that have been collected on Medano Creek; 3) collect or review previously collected water-level data obtained in the area of lower Medano Creek and correlate them with the surface-water data; 4) conduct constant-head permeameter tests on sand samples collected near the ground surface along lower Medano Creek; 5) produce a conceptual model of lower Medano Creek; and 6) produce a numerical model of lower Medano Creek that will …