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Holocene Hydroclimatic and Vegetation Reconstruction in the Sierra Nevada Using Pollen and Stable Isotopes from Convict Lake

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Holocene Hydroclimatic and Vegetation Reconstruction in the Sierra Nevada Using Pollen and Stable Isotopes from Convict Lake University of Kentucky UKnowledge Theses and Dissertations--Earth and Environmental Sciences Earth and Environmental Sciences 2019 HOLOCENE HYDROCLIMATIC AND VEGETATION RECONSTRUCTION IN THE SIERRA NEVADA USING POLLEN AND STABLE ISOTOPES FROM CONVICT LAKE Morgan Black University of Kentucky, [email protected] Author ORCID Identifier: https://orcid.org/0000-0002-1258-7852 Digital Object Identifier: https://doi.org/10.13023/etd.2019.439 Right click to open a feedback form in a new tab to let us know how this document benefits ou.y Recommended Citation Black, Morgan, "HOLOCENE HYDROCLIMATIC AND VEGETATION RECONSTRUCTION IN THE SIERRA NEVADA USING POLLEN AND STABLE ISOTOPES FROM CONVICT LAKE" (2019). Theses and Dissertations--Earth and Environmental Sciences. 76. https://uknowledge.uky.edu/ees_etds/76 This Master's Thesis is brought to you for free and open access by the Earth and Environmental Sciences at UKnowledge. It has been accepted for inclusion in Theses and Dissertations--Earth and Environmental Sciences by an authorized administrator of UKnowledge. For more information, please contact [email protected]. STUDENT AGREEMENT: I represent that my thesis or dissertation and abstract are my original work. Proper attribution has been given to all outside sources. I understand that I am solely responsible for obtaining any needed copyright permissions. I have obtained needed written permission statement(s) from the owner(s) of each third-party copyrighted matter to be included in my work, allowing electronic distribution (if such use is not permitted by the fair use doctrine) which will be submitted to UKnowledge as Additional File. I hereby grant to The University of Kentucky and its agents the irrevocable, non-exclusive, and royalty-free license to archive and make accessible my work in whole or in part in all forms of media, now or hereafter known. I agree that the document mentioned above may be made available immediately for worldwide access unless an embargo applies. I retain all other ownership rights to the copyright of my work. I also retain the right to use in future works (such as articles or books) all or part of my work. I understand that I am free to register the copyright to my work. REVIEW, APPROVAL AND ACCEPTANCE The document mentioned above has been reviewed and accepted by the student’s advisor, on behalf of the advisory committee, and by the Director of Graduate Studies (DGS), on behalf of the program; we verify that this is the final, approved version of the student’s thesis including all changes required by the advisory committee. The undersigned agree to abide by the statements above. Morgan Black, Student Dr. Michael McGlue, Major Professor Dr. Edward W. Woolery, Director of Graduate Studies HOLOCENE HYDROCLIMATIC AND VEGETATION RECONSTRUCTION IN THE SIERRA NEVADA USING POLLEN AND STABLE ISOTOPES FROM CONVICT LAKE _______________________________________ THESIS ________________________________________ A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in the College of Arts and Sciences at the University of Kentucky By Morgan Katherine Black Lexington, Kentucky Director: Dr. Michael McGlue, Professor of Earth and Environmental Sciences Lexington, Kentucky 2019 Copyright © Morgan Katherine Black 2019 https://orcid.org/0000-0002-1258-7852 ABSTRACT OF THESIS HOLOCENE HYDROCLIMATIC AND VEGETATION RECONSTRUCTION IN THE SIERRA NEVADA USING POLLEN AND STABLE ISOTOPES FROM CONVICT LAKE The forested environments of the subalpine and upper montane zones of the eastern Sierra Nevada mountains (California) are biodiverse and valuable ecosystems that are sensitive to hydroclimate changes. The history of high-altitude vegetation changes in the eastern Sierra Nevada is underexplored, and this knowledge gap can be addressed using a paleolimnological approach. In this study, we use a long (~9.5 m) sediment core from Convict Lake, a glacial lake situated in the upper montane zone of California’s Sherwin Range, to assess Holocene changes in terrestrial vegetation. The core was dated using radiocarbon, and studied with palynology, elemental analysis, and stable isotope geochemistry applied to bulk organic matter. Pollen assemblages provide evidence of a dry, open woodland in the Convict Creek watershed during the early Holocene, while the data indicate a stable, cool, and relatively wet mid-Holocene with subalpine forests occurring at lower elevations. All datasets point to considerable hydroclimatic variability beginning around 4,500 yr B.P., which may reflect warmer temperatures and more variable winter precipitation. The presence of the subalpine indicator species Tsuga mertensiana coincides with potential late Holocene glacial advances for which scant evidence currently exists. New insights from this study provide crucial baseline data for comparison with climate simulations of the future for the Sierra Nevada, which serve as the most important water source for vast urban and agricultural areas in California and provide millions of dollars in economic revenue annually. KEYWORDS: Intertropical Convergence Zone, Glacial Advance, Montane Forest, Paleoclimate, Snowpack, Subalpine Morgan Katherine Black __________________________________________ (Name of Student) 9/5/2019 Date HOLOCENE HYDROCLIMATIC AND VEGETATION RECONSTRUCTION IN THE SIERRA NEVADA USING POLLEN AND STABLE ISOTOPES FROM CONVICT LAKE By Morgan Katherine Black Dr. Michael McGlue Director of Thesis Dr. Edward Woolery Director of Graduate Studies 9/5/2019 Date DEDICATION This thesis is dedicated to my entire family. Special dedication is to my grandmother, Nada Earlene Hensley, a dairy farmer and school bus driver who taught me how to have grit, and to work until the job was done. Special dedication is to my mother and father, who have been beacons of light in my life. You have taught me many things, but most importantly, you taught me to persevere. This lesson alone is why I have succeeded. Special dedication is also deserved by Clayton Gullet, who has loved me and sacrificed on my behalf, beyond expectation ACKNOWLEDGMENTS This work would not have been possible if not for the invaluable input received from both my advisor, Dr. Michael McGlue, and Dr. Sarah Ivory. You both have provided me with time, energy, and resources that you did not have to. I will always appreciate this. Dr. Ryan Thigpen has provided me with professional and personal advice that I will carry with me far into the future. I have also received indispensable assistance in the field, the lab, and in life, from Laura Streib, Bailee Hodelka, Joseph Lucas, and Eva Lyon. You all have made me laugh and have provided hugs when I’ve cried. The friendships I have formed with you are equally as valuable to me as the title I will have earned. iii TABLE OF CONTENTS ACKNOWLEDGMENTS………………………………………………......................… iii LIST OF TABLES……………………………………………………......................…… v LIST OF FIGURES……………………………………………………….....................…vi CHAPTER 1. INTRODUCTION…………………………………………....................... 1 1.1 STUDY LOCATION…………………………………….......................... 5 1.2 GEOLOGY…………………………………………….......................….. 7 1.3 GLACIAL HISTORY…………………………………........................…. 8 1.4 MODERN CLIMATE AND VEGETATION…………........................…. 9 1.5 MODERN POLLEN RAIN…………………………….......................…. 10 1.6 PREVIOUS RESEARCH……………………………….......................… 12 CHAPTER 2. METHODS……………………………………………........................….. 20 2.1 POLLEN ANALYSIS…………………………………........................… 21 2.2 BULK AND STABLE ISOTOPE GEOCHEMISTRY…........................... 23 CHAPTER 3. RESULTS………………………………………………............................ 29 3.1 DETRENDED CORRESPONDENCE ANALYSIS……….......................33 3.2 CHEMOSTRATIGRAPHIC RESULTS……………….............................34 CHAPTER 4. DISCUSSION……………………………………………......................... 40 4.1 USE AND IMPLICATIONS OF POLLEN AND GEOCHEMICAL DATA………………………………………………………….......................….. 40 4.2 EARLY HOLOCENE (ZONES 1-3, 9,380 - 8,800 YR B.P.)......................... 42 4.3 MIDDLE HOLOCENE (ZONES 3-5, 8,800 TO 4,490 KYR B.P.)….............45 4.4 LATE HOLOCENE (4,490 KYR B.P. - PRESENT)…………....................... 49 CHAPTER 5. CONCLUSIONS…………………………………………….....................59 APPENDICES APPENDIX A. POLLEN DATA (PERCENTAGES)………………....................62 APPENDIX B. STABLE ISOTOPE AND BULK GEOCHEMICAL DATA…………………………………………………………………..................72 REFERENCES………………………………………………………………....................76 VITA…………………………………………………………………………....................93 iv LIST OF TABLES Table 1. Coring Location Data…………………………………………..................…………. 25 Table 2. Radiocarbon Dates………………………………………………....................……… 25 v LIST OF FIGURES Figure 1. Location Description…………………………………………....................……… 16 Figure 2. Digital Elevation Model…………………………………………...................…….17 Figure 3. Historical Climate Data……………………………………………....................….18 Figure 4. Vegetation Zones……………………………………………………...................... 19 Figure 5. Age Model………………………………………………………...................…..….26 Figure 6. Pollen Zonation………………………………………………..................………....27 Figure 7. A:C…………………………………………………….………...................……….28 Figure 8. Common Pollen Types………………………………………..................………….37 Figure 9. Detrended Correspondence Analysis……………………………….................……38 Figure 10. Chemostratigraphy………………………………………………..................…….39 Figure 11. Pinus vs. A:C……………………………………………………..................…….58 vi 1.
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