Joseph M. Licciardi for the Degree of Doctor of Philosophy in Geology Presented On

AN ABSTRACT OF THE DISSERTATION OF Joseph M. Licciardi for the degree of Doctor of Philosophy in Geology presented on September 26, 2000. Title: Alpine Glacier and Pluvial Lake Records of Late Pleistocene Climate Variability in the Western United States. Redacted for privacy Abstract approved: Peter U. Clark This investigation focuses on the development of Quaternary dating techniques to construct high-resolution numerical chronologies of late-Pleistocene climate variability in the western United States. Cosmogenic 3He concentrations were measured in radiocarbon-dated olivine-bearing Holocene lava flows in Oregon, yielding a mean production rate of 116 ± 3 3He atoms g1 yf'. This value is consistent with previous estimates at mid-latitides, and helps refine the accuracy of the cosmogenic 3He dating technique. Cosmogenic 3He and 10Be chronologies were developed for well-preserved moraine sequences in the northern Yellowstone region, Montana, and in the Wallowa Mountains, Oregon. Cosmogenic data indicate that the northern outlet glacier of the Yellowstone ice cap reached its terminal moraine at 16.7 3He ka / 16.2 '°Be ka, and retreated to 50% of its maximum extent by13.8 ka. In the Wallowa Mountains, two major late-Pleistocene alpine glacier advances occurred at21 and -'17 ka, and a minor advance occurred at '-41 ka. The '-21 ka advance in the Wallowa Mountains coincides with the last glacial maximum, and is correlative with the last Pinedale maximum advance in the Wind River Mountains. The '-47 ka advance in the Wallowa Mountains is probably correlative with the advance of the northern Yellowstone outlet glacier. The youngest event in the Wallowa Mountains, at -11 ka, may be correlative to an advance that deposited the Titcomb Lakes moraines in the Wind River Mountains during the Younger Dryas. New accelerator mass spectrometry radiocarbon ages from gastropods in shore deposits within the pluvial Lake Chewaucan basin, Oregon, identify a significant lake level high at12 '4C ka. The Chewaucan lake-level high is coeval with lake-level lows in the Bonneville and Lahontan basins, and with a period of relatively wet conditions in the more southerly Owens Lake basin. This spatial pattern of pluvial lake levels in the western U.S. at12 14C ka indicates a variable synoptic response to climate forcing at this time. These new data contribute critically needed geographic coverage to existing glacial and pluvial lake records for examining spatial and temporal late- Pleistocene climate variability in western North America. ©Copyright by Joseph M. Licciardi September 26, 2000 All Rights Reserved Alpine Glacier and Pluvial Lake Records of Late Pleistocene Climate Variability in the Western United States by Joseph M. Licciardi A DISSERTATION submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Presented September 26, 2000 Commencement June 2001 Doctor of Philosophy dissertation of Joseph M. Licciardi presented on September 26, 2000 APPROVED: Redacted for privacy Major Professor, representing Geology Redacted for privacy Chair of Department of Geoscien 's Redacted for privacy C- Dean of Gras hoo1 I understand that my dissertation will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my dissertation to any reader upon request. Redacted for privacy Joseph M. Licciardi, Author Acknowledgments During my 8 years of graduate studies at Oregon State University, I have received valuable guidance and advice from nearly every faculty member of the Department of Geosciences, and from a number of faculty members of the College of Oceanic and Atmospheric Sciences. Foremost among these, I thank Peter Clark for ongoing inspiration, encouragement, and support throughout his long tenure as my advisor and mentor. He provided numerous thoughtful reviews of the manuscripts, and has supplied me with a veritable plethora of interesting ideas. And he let me graduate. The entire office staff helped immeasurably in wading through the logistics of getting through graduate school. In this capacity, Therese Belden deserves special mention for her many years of cheerful advice and help. Of those outside the confines of Corvallis, I thank Ed Brook at Washington State University for invaluable guidance and frequent advice on a wide range of topics. Mark Kurz was kind enough to host me during my visit to the Woods Hole Oceanographic Institution. I am grateful to David Elmore and Pankaj Sharma for hosting me during my visit to PRIME lab at Purdue University, and for all the hours they invested in the challenges of obtaining the beryllium data. I thank Grant Raisbeck and Francoise Yiou for helpful advice on various data puzzles, and for hosting me and touring me through their facilities at the University of Paris. Lionel Siame, Jean-Francoise Ritz, and Helene Imbaud are also thanked for their French hospitality during my stay. I thank Bill McCoy, Eric Oches, and Julie Brigham-Grette for guidance in their amino acid lab at the University of Massachusetts, Amherst; although I didn't use any of the data I obtained at their lab, I learned a great deal. Additional contributions by other individuals and sources of funding are acknowledged in each manuscript. I am especially indebted to the enormous support, both scientifically and socially, from a long list of past and present graduate students in the department, as wellas friends outside the department, who created a very enjoyable atmosphere where hard work and hard play were often very well-balanced, and sometimes not so well-balanced. Of these, I would particularly like to thank Lisa McNeill, whose enduring friendship and moral support have helped make life in Corvallis and in the department a pleasure. Above all, I would like to thank my parents for their continuing encouragement and support during my seemingly interminable stay at a university on the opposite side of the country; I can never thank them enough. Contribution Of Authors With the exception of Chapter 3, which is a single-authored paper, the manuscripts in this dissertation are the products of collaborations with several other co- authors. As a co-author of Chapters 2, 4, and5,Peter U. Clark was instrumental in the conception, direction, and completion of the work described in these chapters, and contributed significantly to the organization and editing of the manuscripts. Although he is not an author on Chapter 3, Peter also deserves credit for directing me towards this work, and provided insightful criticism as the paper evolved. As a co-author of Chapters 2, 4, and5,Edward J. Brook provided advice on field sampling methodologies, guidance in the development of laboratory procedures, and assistance in the interpretation of the final results and the editing of these manuscripts. As a co-author of Chapters 2 and 4, Mark D. Kurz oversaw the analysis of the helium measurements at the Woods Hole Oceanographic Institution, and contributed to the interpretation of the helium data and the organization of these manuscripts. As a co-author of Chapter 4, Kenneth L. Pierce assisted with identification of sample sites in the field, and was involved with the interpretation of the final results. As co-authors of Chapters 4 and5,David Elmore and Pankaj Sharma oversaw the analysis of the beryllium measurements at PRIME lab at Purdue University, and contributed significantly to the derivation of the final results. Table Of Contents Page Chapter 1Introduction 1 1.1 Foreword 1 1.2 References 4 Chapter 2Calibration Of Cosmogenic 3He Production Rates from Holocene Lava Flows in Oregon, USA, and Effects of the Earth's Magnetic Field . 7 2.1 Abstract 8 2.2 Introduction 8 2.3 Samples 9 2.4 Determination of Cosmogenic Helium Content 13 2.5 Results and Discussion 14 2.5.1 Sources of Uncertainty 14 2.5.2 Comparison to Previous Calibrations of Production Rates 17 2.5.3 Effect of Olivine Composition on Production Rate 20 2.5.4 Effect of Dipole Moment Fluctuations on Production Rate 21 2.5.5 Effect of Secular Variation of Dipole Axis Position on Production Rate 24 2.6 Conclusions 26 2.7 Acknowledgments 26 2.8 References 27 Chapter 3Chronology of Latest Pleistocene Lake-Level Fluctuations in the Pluvial Lake Chewaucan Basin, Oregon, USA 31 3.1 Abstract 32 3.2 Introduction 32 Table Of Contents, Continued Page 3.3 Methods 33 3.4 Results ...35 3.4.1 Latest-Pleistocene Fan Delta in Lower Chewaucan Marsh 35 3.4.2 Latest-Pleistocene Shorelines at Lake Abert 36 3.5 Discussion 39 3.5.1 Sources of Uncertainty in Gastropod Ages 39 3.5.2 Tectonic Concerns 41 3.5.3 Hypsometric and Geomorphic Considerations 41 3.5.4 Latest Pleistocene Lake-level History of Pluvial Lake Chewaucan 43 3.5.5 Comparisons to Other Great Basin Paleolake Records 47 3.5.6 Implications for mechanisms of climate change 48 3.6 Conclusions 50 3.7 Acknowledgments 51 3.8 Appendix: Additional Sample Details 51 3.9 References 52 Chapter 4Cosmogenic 3He and 10Be Chronologies of the Northern Outlet Glacier of the Yellowstone Ice Cap, Montana, USA 58 4.1 Abstract 59 4.2 Introduction 59 4.3 Sampling Strategy 61 4.4 Cosmogenic 3He and '°Be Measurements 61 Table Of Contents, Continued Page 4.5 Production Rates and Scaling Methods 65 4.5.1 Scaling of Production Rates 65 4.5.2 Cosmogenic 3He Production Rate 66 4.5.3 Cosmogenic '°Be Production Rate 66 4.5.4 Magnetic Field Effects on Production Rates ..67 4.5.5 True Accuracy of Cosmogenic Ages .67 4.6 Geological Uncertainties 68 4.7 Analytical and Other Sources

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