Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies, School of 12-13-2011 Reconstructing the Holocene Arroyo History of the Upper Escalante River, Southern Utah, Using Optically Stimulated Luminescence (OSL) and Radiocarbon Dating Anne E. Hayden Utah State University Recommended Citation Hayden, Anne E., "Reconstructing the Holocene Arroyo History of the Upper Escalante River, Southern Utah, Using Optically Stimulated Luminescence (OSL) and Radiocarbon Dating" (2011). All Graduate Theses and Dissertations. Paper 1105. http://digitalcommons.usu.edu/etd/1105 This Thesis is brought to you for free and open access by the Graduate Studies, School of at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. RECONSTRUCTING THE HOLOCENE ARROYO HISTORY OF THE UPPER ESCALANTE RIVER, SOUTHERN UTAH, USING OPTICALLY STIMULATED LUMINESCENCE (OSL) AND RADIOCARBON DATING by Anne E. Hayden A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Geology Approved: Tammy Rittenour, Ph.D. Janis Boettinger, Ph.D. Major Professor Committee Member Joel Pederson, Ph.D. Byron R. Burnham, Ed.D. Committee Member Dean of Graduate Studies UTAH STATE UNIVERSITY Logan, Utah 2011 ii Copyright © Anne E. Hayden 2011 All Rights Reserved iii ABSTRACT Reconstructing the Holocene Arroyo History of the Upper Escalante River, Southern Utah, Using Optically Stimulated Luminescence (OSL) and Radiocarbon Dating by Anne E. Hayden, Master of Science Utah State University, 2011 Major Professor: Dr. Tammy M. Rittenour Department: Geology Arroyos are steep-walled, entrenched, typically ephemeral streams commonly found in dryland river systems that form when streams incise into previously deposited alluvial fill. Arroyos in the southwestern U.S. have been studied extensively following the historic period of arroyo cutting in the late 1800s and early 1900s A.D. The upper Escalante River in south-central Utah similarly began incising in 1909, and records evidence for past cut and fill cycles in well-exposed walls along the now continuous arroyo. Establishing robust geochronologies of past arroyo cycles in these fluvial settings has been difficult. Recent improvements in accelerator mass spectrometry (AMS) radiocarbon (14C) and optically stimulated luminescence (OSL) dating provide an opportunity to link more highly resolved fluvial records to existing paleoclimate records. This allows hypotheses regarding the causes of arroyo cycles to be tested, and for the role of climate versus intrabasinal characteristics to be examined. One major objective of this research was to examine the applicability of OSL and AMS 14C dating in the upper Escalante, as both methods have proved problematic in iv similar settings. In total, 37 ages were obtained, 21 OSL and 16 14C ages. The Holocene fluvial history of the upper Escalante River was reconstructed using these age results and stratigraphic relationships. The chronostratigraphic record developed in this study suggests that at least six arroyo cycles have occurred in the upper Escalante since the middle Holocene, with incision occurring ~4.4 – 4.2 ka, ~2.6 – 2.4 ka, ~1.8 – 1.5 ka, ~1.0 – 0.9 ka, ~0.5 - 0.4 ka, and during the historic period of arroyo entrenchment. While semi-synchronous arroyo cutting (indicative of a climate signal) appears to have occurred in the Paria and Escalante drainages over the last 1 ka, correlations between proximal drainages are less clear prior to 1 ka, although this may be due in part to preservation effects. Overall, linkages to specific climate regimes and correlations to regional drainages are difficult to identify, suggesting that internal geomorphic thresholds are important in determining when arroyo entrenchment occurs in individual catchments. (235 pages) v ACKNOWLEDGMENTS I would like to start by thanking my advisor, Tammy Rittenour, for giving me the opportunity to work on an immensely interesting project in one of the most beautiful places I know. Her support and feedback were essential to the success of this research project. I truly appreciate her enthusiasm for geomorphology and geochronology, and know that I am a better scientist because I had the opportunity to work with her. Further, I was extremely fortunate to work at USU’s Luminescence Laboratory, and am grateful to Tammy for providing such a unique and first-hand opportunity to learn about optically stimulated luminescence dating. Additionally, I would like to thank committee members Joel Pederson and Janis Boettinger. I learned a great deal in my interactions with them both in and out of the classroom. I truly appreciate the time they spent editing this document, as I know it is a stronger product because of their input. I would like to acknowledge a number of organizations for generous financial support that made this research project possible, including the USGS EDMAP Program (grant award number G09AC00141), the Geological Society of America Graduate Student Research Grant program, the SEPM (Society for Sedimentary Geology) Student Assistance Grant, and the Association for Women Geoscientists – Salt Lake Chapter Research Scholarship. Additionally, I would like to thank the USU Geology Department for offering financial assistance by awarding me the J. Stewart Williams scholarship as well as by providing opportunities to act as both a research and teaching assistant. I am particularly indebted to the USU Luminescence Laboratory and the University of Arizona AMS Laboratory’s Student Internship program. Both provided the opportunity to process a greater number of samples than would have been otherwise possible, which certainly enhanced the quality of this research. vi Special thanks go out to all those who helped in the field and/or lab, including Michelle Summa Nelson, Jon Harvey, Melissa Jackson, Pete Kolbenschlag, and Demaree. I would also like to sincerely thank Steve Roberts, Escalante Outfitters, for providing me with a scenic spot to camp in my study area. Finally, I would like to thank my family and friends for their support throughout this process. I am especially grateful to many of the USU geology graduate students who helped keep things in perspective and provided a good laugh when it was needed most. Anne Hayden vii CONTENTS ABSTRACT ...........................................................................................................iii ACKNOWLEDGMENTS ........................................................................................ v LIST OF TABLES ................................................................................................. ix LIST OF FIGURES ................................................................................................ x LIST OF PLATES ................................................................................................ xiii CHAPTER 1. INTRODUCTION ....................................................................................... 1 2. GEOCHRONOLOGY OF THE UPPER ESCALANTE RIVER ................... 3 ABSTRACT................................................................................................ 3 2.1 Introduction and background ......................................................... 4 2.2 Study area and geomorphic setting ............................................... 6 2.3 Radiocarbon dating and applications in fluvial settings ................. 9 2.4 OSL dating and applications in fluvial settings ............................. 10 2.5 Methods ....................................................................................... 12 2.6 Optical measurements ................................................................. 22 2.7 Calculation of ages ...................................................................... 28 2.8 Results ......................................................................................... 38 2.9 Discussion .................................................................................... 54 2.10 Conclusions ................................................................................. 59 REFERENCES ........................................................................................ 60 3. ARROYO CYCLES IN THE UPPER ESCALANTE RIVER ..................... 64 ABSTRACT.............................................................................................. 64 3.1 Introduction .................................................................................. 65 3.2 Study area .................................................................................... 69 3.3 Background and previous work .................................................... 75 3.4 Methods ....................................................................................... 87 3.5 Geomorphology of study area ...................................................... 95 3.6 Stratigraphy .................................................................................. 99 3.7 Chronostratigraphy .................................................................... 121 3.8 Regional correlations and paleoclimate implications ................. 138 3.9 Conclusions ............................................................................... 154 REFERENCES ...................................................................................... 156 viii 4. MAPPING OF THE UPPER ESCALANTE RIVER CORRIDOR ...........