University of New Mexico UNM Digital Repository Earth and Planetary Sciences ETDs Electronic Theses and Dissertations Summer 7-15-2020 Fluvial Geomorphic and Hydrologic Evolution and Climate Change Resilience in Young Volcanic Landscapes: Rhyolite Plateau and Lamar Valley, Yellowstone National Park Benjamin Newell Burnett University of New Mexico Follow this and additional works at: https://digitalrepository.unm.edu/eps_etds Part of the Geology Commons, Geomorphology Commons, and the Hydrology Commons Recommended Citation Burnett, Benjamin Newell. "Fluvial Geomorphic and Hydrologic Evolution and Climate Change Resilience in Young Volcanic Landscapes: Rhyolite Plateau and Lamar Valley, Yellowstone National Park." (2020). https://digitalrepository.unm.edu/eps_etds/275 This Dissertation is brought to you for free and open access by the Electronic Theses and Dissertations at UNM Digital Repository. It has been accepted for inclusion in Earth and Planetary Sciences ETDs by an authorized administrator of UNM Digital Repository. For more information, please contact [email protected], [email protected], [email protected]. i Benjamin Newell Burnett Candidate Earth and Planetary Sciences Department This dissertation is approved, and it is acceptable in quality and form for publication: Approved by the Dissertation Committee: Dr. Grant Meyer , Chairperson Dr. Peter Fawcett Dr. Leslie McFadden Dr. Julia Coonrod ii FLUVIAL GEOMORPHIC AND HYDROLOGIC EVOLUTION AND CLIMATE CHANGE RESILIENCE IN YOUNG VOLCANIC LANDSCAPES: RHYOLITE PLATEAU AND LAMAR VALLEY, YELLOWSTONE NATIONAL PARK. by BENJAMIN NEWELL BURNETT BS, Earth and Environmental Sciences, Lehigh University, 2001 BA, Anthropology, Lehigh University, 2001 MS, Earth and Planetary Sciences, University of New Mexico, 2004 DISSERTATION Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Earth and Planetary Sciences The University of New Mexico Albuquerque, New Mexico July, 2020 iii ACKNOWLEDGEMENTS This work would not have been possible without Bethany Burnett, who was my source of greatest support at home and in the field. I must also thank Dr. Grant Meyer who has served as my advisor and greatest academic ally. For four summer seasons I ventured into the wilderness of Yellowstone National Park with the following intrepid field assistants who were all invaluable to the completion of this work: Niky Taylor, Joe Galarza, Lauren Goldfarb, Ehren Baca, Nick Freymueller and Andres Bader-Elenes. I would also like to thank the UNM EPS department for providing continuous support and opportunities to teach a wide range of Earth and environmental science courses both as a TA and primary instructor. Funding for this research was generously provided by the EPS Black / EEE Fellowship and Jean-Luc Miossec Memorial Scholarship. iv Fluvial Geomorphic and Hydrologic Evolution and Climate Change Resilience in Young Volcanic Landscapes: Rhyolite Plateau and Lamar Valley, Yellowstone National Park By Benjamin Newell Burnett BS, Earth and Environmental Sciences, Lehigh University, 2001 BA, Anthropology, Lehigh University, 2001 MS, Earth and Planetary Sciences, University of New Mexico, 2004 PhD, Earth and Planetary Sciences, University of New Mexico, 2020 ABSTRACT Quaternary volcanism associated with the last caldera cycle in Yellowstone included emplacement of ash-flow tuffs, massive rhyolite flows ranging from 79 to 484 ka, and valley-filling basalts. This study examines (1) the evolution of spring hydrology with flow age on the Rhyolite Plateau, (2) initial development and evolution of stream networks on the rhyolite flows, and (3) the impact of the 630 ka caldera formation and volcanic flow emplacement on Lamar Valley incision rates. Integrated stream networks formed within 79 kyr on the Rhyolite Plateau. Incision is focused on steep flow margins and knickpoints and is dependent on local stream power. Plugging of fractures causes hydraulic conductivity of the flows to decline over time. Snowmelt infiltrates rapidly into younger flows, leaving ephemeral surface streams, but many flow-margin springs experience a delayed snowmelt response and enhanced v discharge during late-summer periods of water stress, providing important refugia for aquatic organisms threatened by climate change. Incision rates over the past 630 kyr in the Lamar Valley are greatest (≤ 0.55 mm/yr) where the greatest thickness of Quaternary volcanic material was emplaced, where they are higher than most rivers in the region. Incision rates are lowest (≤ 0.15 mm/yr) above a knickpoint caused by erosion resistant crystalline bedrock, and in the upper reaches of two tributaries, where I infer that faulting associated with caldera formation led to stream capture of portions of the headwater areas. vi Table of Contents Chapter 1: Control of Rhyolite Flow Age on Summer Season Hydrology and Resilience of Freshwater Streams and Springs to Climate Variability on the Rhyolite Plateau, Yellowstone National Park. .............................................................................................. 1 1. Abstract: ......................................................................................................................... 1 2. Introduction and Study Area:......................................................................................... 3 2.1 Climatic and geologic controls on summer discharge ............................................ 4 2.2 Geology of the Yellowstone volcanic field ........................................................... 10 2.3 Characteristics of streams and springs on the Rhyolite Plateau .......................... 13 3. Methods ....................................................................................................................... 14 4. Results .......................................................................................................................... 21 5. Discussion..................................................................................................................... 29 5.1 Aquifer characteristics and connectivity to surface waters ................................. 30 5.2 Delayed snowmelt pulses ..................................................................................... 34 5.3 Evolution of hydrology on the Rhyolite Plateau ................................................... 37 5.4 Resilience .............................................................................................................. 43 6. Conclusions .................................................................................................................. 46 7. References ................................................................................................................... 49 Chapter 2: Initial Development and Evolution of Stream Networks and Longitudinal Profiles on Young Rhyolite Flows, Yellowstone National Park, and the Importance of Volcanic Bedrock Structures ........................................................................................... 54 1. Abstract ........................................................................................................................ 54 2. Introduction ................................................................................................................. 55 2.1 Study area ............................................................................................................. 58 2.2 Measures of stream network morphology and incision ...................................... 63 3. Methods and Results ................................................................................................... 68 3.1 Hypsometry .......................................................................................................... 68 3.2 Definition of drainage network ............................................................................ 70 3.3 Drainage basin delineation and shape factors ..................................................... 73 3.4 Drainage density and stream frequency .............................................................. 76 vii 3.5 Tributary junction angles ...................................................................................... 78 3.6 Slope-Area relationship ........................................................................................ 85 3.7 Stream incision and concavity .............................................................................. 88 4. Discussion..................................................................................................................... 95 4.1 Suitability of the Rhyolite Plateau for space-for-time substitution ..................... 95 4.2 Influence of glaciation on plateau morphology and stream systems .................. 97 4.3 Evolution of stream concavity ............................................................................ 100 4.4 Evolution of the stream network ....................................................................... 103 5. Conclusions ................................................................................................................ 109 6. References ................................................................................................................. 112 Chapter 3: Profile Adjustments of the Lamar River and its Tributaries Following Catastrophic Volcanism: Lithologic, Volcanic and Tectonic Controls on Incision and Stream Capture, Yellowstone National Park ............................................................................