Constraining Ice Advance and Linkages to Paleoclimate of Two Glacial Systems in the Olympic Mountains, Washington
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CONSTRAINING ICE ADVANCE AND LINKAGES TO PALEOCLIMATE OF TWO GLACIAL SYSTEMS IN THE OLYMPIC MOUNTAINS, WASHINGTON AND THE SOUTHERN ALPS, NEW ZEALAND by Cianna E. Wyshnytzky A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Geology Approved: _________________________ _________________________ Dr. Tammy Rittenour Dr. Glenn D. Thackray Major Professor Committee Member _________________________ _________________________ Dr. Joel L. Pederson Dr. Mark R. McLellan Committee Member Vice President for Research and Dean of the School of Graduate Studies UTAH STATE UNIVERSITY Logan, Utah 2013 Copyright © Cianna E. Wyshnytzky 2013 All Rights Reserved iii ABSTRACT Constraining Ice Advance and Linkages to Paleoclimate of Two Glacial Systems in the Olympic Mountains, Washington and the Southern Alps, New Zealand by Cianna E. Wyshnytzky, Master of Science Utah State University, 2013 Major Professor: Tammy M. Rittenour Department: Geology This thesis investigated marine isotope stage (MIS) 3-2 glacial sequences in the South Fork Hoh River Valley, Washington and the Lake Hawea Valley, New Zealand. Research objectives were to reconstruct the style and timing of ice advance in both areas and to assess the viability of luminescence dating of glacial sediments in various depositional facies and distances from the ice front. This thesis focused on the sedimentology and stratigraphy of surficial and older glacial sequences in the South Fork Hoh and Lake Hawea areas and used OSL and radiocarbon dating techniques to establish age control for the deposits. Specifically, this research identified, described, and dated the stratigraphy of glacial sequences in order to reconstruct ice dynamics. This work also presents updated geomorphic maps for both study areas as an additional way to show ice advance and retreat events recorded in deposited sediment and geomorphic surfaces. The glacial sequence expressed in the Lake Hawea moraine exposure shows four distinct depositional events that represent retreat from an ice position down-valley, re-advance to the iv Hawea moraine position, and subsequent retreat and deglaciation broadly spanning ~32-18 ka. These results document the terminal glacial advance and subsequent retreat in the Lake Hawea Valley and contribute to the wider swath of research studying the last phase of glacial retreat and its connections to climate on the South Island of New Zealand. The Hawea chronology corresponds to other glacial records and paleoclimate reconstructions from the South Island that collectively suggest the commencement of deglaciation at ~18 ka. Three late Pleistocene ice positions are preserved in the South Fork Hoh River Valley, here referred to as South Fork 1-3 (SF 1-3). One of these positions has not previously been recognized in this valley or in the mainstem Hoh River Valley. Optically stimulated luminescence (OSL) and radiocarbon (14C) ages are generally consistent throughout the valley. These findings advocate for a detailed sedimentologic and stratigraphic approach to glacial deposits and questions whether a similar advance or still-stand occurred in other valleys in the region. If so, this may reveal information regarding climate influences on MIS 2 glaciers in the Olympic Mountains. This research also assesses the applicability of OSL dating to glacial deposits in both field areas. Quartz OSL dating was used in the South Fork Hoh study area; however, quartz produced unreliable results in the Hawea study area, so samples were therefore assessed using feldspar methods. The results advocate for a facies-based sampling approach in glacial settings, where better sorted sandy facies and more distal deposits produce better bleached and more reliable age results than other deposits. (206 pages) v PUBLIC ABSTRACT Constraining ice advance and linkages to paleoclimate of two glacial systems in the Olympic Mountains, Washington and the Southern Alps, New Zealand by Cianna E. Wyshnytzky, Master of Science Utah State University, 2013 Major Professor: Tammy M. Rittenour Department: Geology This thesis investigates glacial sediments in the South Fork Hoh River Valley, Washington and the Lake Hawea Valley, New Zealand that were deposited during the last glacial period. Research objectives were to reconstruct the style and timing of glacier advance and retreat in both areas and to assess the viability of luminescence dating of sediments in glacial environments. Glaciers are influenced primarily by temperature and precipitation. Valley glaciers, like those in the Olympics Mountains and Southern Alps, are thought to respond relatively rapidly to climate fluctuations in comparison to continental ice sheets. Understanding how these glacial systems responded to past climate fluctuations therefore holds importance for understanding how modern glaciers, which are important for water resources and stream-flow habitat, may respond to future climate change. Fieldwork for this project was conducted over the course of approximately ten weeks, during which sites in the Olympic Mountains and Southern Alps were visited, described, and vi sampled. Chronologic constrain on sediment deposition was obtained through radiocarbon and luminescence dating. Radiocarbon samples were sent to the Lawrence Livermore National Laboratory for analysis, whereas luminescence samples were processed and analyzed at the Utah State University Luminescence Laboratory. Funding for this project was obtained from National Science Foundation grants (NSF-EAR 1024657 and 1024850) and awards from the Utah State University Department of Geology. vii DEDICATION Some may find it odd to dedicate a thesis to a furry, four-legged friend. This thesis, however, is dedicated to Geo the dog, who adopted me shortly after my arrival in Utah. This boy has forced me to take invaluable breaks from my work, has proven to be an excellent fieldwork companion, and has a remarkable ability to put a smile on my face when needed. He’s also the best fieldwork companion a girl could ask for. You, Big G, have played the biggest role in maintaining my sanity, and I look forward to many more years. viii ACKNOWLEDGMENTS I would sincerely like to thank the National Science Foundation, the USU Department of Geology, and the ISU of Department of Geosciences for their generous funding and support of this research project. I would also like to acknowledge and especially thank Michelle Summa Nelson at the USU Luminescence Laboratory for her endless help in sample analysis. I am grateful for my committee members, Glenn Thackray and Joel Pederson, for their help throughout the past two years. Courses with Joel helped me especially refine mapping, field, and writing skills, and his perspective as a non-glacial geomorphologist has been important as a set of eyes and ears outside the project. This project would not have been possible without Glenn’s previous work and continued interest in unraveling the history of glaciation in the Olympic Mountains and Southern Alps. His expertise and experience in both field areas has been crucial to fieldwork planning and interpretations. As the biggest proponent of tea time, fine wines and cheeses, and skipping stones in the field, Glenn’s presence during trips extended to maintaining positive morale and providing the important perspective of fun and relaxation in any situation. I would especially like to thank Tammy Rittenour, my primary adviser, for the opportunity to join the graduate program at USU through full funding. Tammy spent countless hours editing grant proposals and thesis drafts, writing references, and discussing data and interpretations associated with my work. Her encouragement and support in presenting my research as various conferences significantly impacted dissemination of my research and confidence in my presenting skills. I will be continually grateful for the opportunity that I have had to work in the Luminescence Lab, and look forward to continued collaboration with Tammy in published chapters of my thesis. I will continue to “take one for the team” with your voice echoing in my head, Tammy. ix Many thanks to others that played significant parts in this research. The National Park Service authorized research access and collecting permits for Olympic National Park. Katie Marshall assisted greatly with fieldwork, and her companionship on the coast and in the rainforest was ever-valuable. Jamie Shulmeister, as well as his students Olivia Hyatt and Lucas Evans, and Allan Ashworth provided valuable insight in the field and through email correspondence. Lastly, I would like to thank my family and friends for their support from afar and my friends in Logan for their feedback, adventures, and camaraderie. Cianna E. Wyshnytzky x CONTENTS Page ABSTRACT .......................................................................................................................................iii PUBLIC ABSTRACT............................................................................................................................v DEDICATION...................................................................................................................................vii ACKNOWLEDGEMENTS.................................................................................................................viii LIST OF TABLES.............................................................................................................................. xiii LIST OF FIGURES...........................................................................................................................