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Millennial-Scale Variability of a Major East Antarctic Outlet Glacier During the Last Glaciation Michelle Guitard University of South Florida, [email protected]

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Millennial-Scale Variability of a Major East Antarctic Outlet Glacier During the Last Glaciation Michelle Guitard University of South Florida, Mguitard@Mail.Usf.Edu University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School 10-19-2015 Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation Michelle Guitard University of South Florida, [email protected] Follow this and additional works at: http://scholarcommons.usf.edu/etd Part of the Geology Commons Scholar Commons Citation Guitard, Michelle, "Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation" (2015). Graduate Theses and Dissertations. http://scholarcommons.usf.edu/etd/5957 This Thesis is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Millennial-scale Variability of a Major East Antarctic Outlet Glacier during the Last Glaciation by Michelle E. Guitard A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Marine Science with a concentration in Geological Oceanography College of Marine Science University of South Florida Major Professor: Amelia E. Shevenell, Ph.D. Eugene W. Domack, Ph.D. Brad E. Rosenheim, Ph.D. Date of Approval: November 3, 2015 Keywords: Amery Ice Shelf, radiocarbon, cosmogenic beryllium-10, millennial-scale variability Copyright © 2015, Michelle E. Guitard ACKNOWLEDGMENTS I want to say a huge thank you to those who helped and supported me through my Masters degree. Thank you to my major advisor, Amelia Shevenell, who works so hard for her students. She inspires me to work hard and to always keep learning. Thank you to my committee members, Brad Rosenheim and Eugene Domack, for their insight and guidance on this project. Thank you also to Amy Leventer at Colgate University, and Yusuke Yokoyama and his lab at the Atmosphere and Ocean Research Institute, University of Tokyo for their mentorship in the laboratory and in the field. Thank you to the Australian researchers who have devoted their time to investigating the Prydz Bay region and for their scientific collaboration. Thank you to the crew and support staff aboard the Research Vessels Nathaniel B. Palmer and Aurora Australis for their assistance on cruises NBP01-01, AA-186, and KROCK. Thank you to the faculty, staff and students of the Paleo Lab at the College of Marine Science for making the lab experience a great one. Last, but certainly not least, thank you to my friends and family who have supported me through the triumphs and the tears. Your love and support mean the world to me. ! TABLE OF CONTENTS List of Tables ................................................................................................................................. iii List of Figures ................................................................................................................................ iv Abstract ........................................................................................................................................... v Introduction .................................................................................................................................... 1 Background ......................................................................................................................... 1 Study Location .................................................................................................................... 2 Methods ........................................................................................................................................... 8 Physical Properties Analyses .............................................................................................. 8 Development of Marine Composite Depth Scale ................................................................ 8 Ramped Pyrolysis Preparation for Radiocarbon Analysis .................................................. 8 Radiocarbon Analysis, Correction and Calibration ............................................................. 9 Beryllium-10 Preparation .................................................................................................... 9 Results and Discussion .................................................................................................................. 11 Physical Properties ............................................................................................................ 11 Radiocarbon ...................................................................................................................... 11 Beryllium-10 .................................................................................................................... 12 Regional Glacial and Oceanic Fluctuations: Timing and Variability ............................... 14 Conclusions ................................................................................................................................... 17 References ..................................................................................................................................... 18 Appendix A: Extended Data ......................................................................................................... 22 Extended Data Figure 1 ..................................................................................................... 22 Extended Data Figure 2 ..................................................................................................... 23 Extended Data Table 1 ...................................................................................................... 24 Extended Data Table 2 ...................................................................................................... 26 Extended Data Table 3 ...................................................................................................... 27 Extended Data Table 4 ...................................................................................................... 28 Appendix B: Supplementary Methods .......................................................................................... 29 Radiocarbon Contamination Correction ............................................................................ 29 Calibration ......................................................................................................................... 31 Beryllium-10 Concentration Corrections .......................................................................... 31 ! i Beryllium-10 Budget Estimates ....................................................................................... 32 Appendix C: Supplementary Discussion ....................................................................................... 34 Diatom Assemblages ......................................................................................................... 34 Appendices References ................................................................................................................. 36 ! ! ii LIST OF TABLES Extended Data Table 1: Percent diatom abundance (%abundance) from NBP01-01 JPC-34, -35, and -36 SMO units .................................................................................. 24 Extended Data Table 2: Prydz Channel 14C and cal BP ages, δ 13C, and %TOC ........................ 26 Extended Data Table 3: NBP01-01 ramped pyrolysis 14C ages, RP temperature range, uncorrected and corrected Fm values ............................................................................ 27 Extended Data Table 4: Aliquot weight, uncorrected and corrected 10Be abundance with associated error, and flux for NBP01-01 cores ............................................................ 28 ! ! ! ! iii LIST OF FIGURES Figure 1: Prydz Channel, East Antarctica, depicting multibeam swath bathymetry, core locations ......................................................................................................................... 5 Figure 2: NBP01-01 core stratigraphy, magnetic susceptibility (MS), % diatom abundance, 10Be concentration ([10Be]) alongside Prydz Channel composite MS and radiocarbon (14C) ages ................................................................................................... 6 Figure 3: Improved acid insoluble organic matter (AIOM) radiocarbon (14C) ages derived from the ramped pyrolysis (RP) technique .................................................................... 7 Figure 4: Oceanic and climatic millennial-scale variability ......................................................... 16 Extended Data Figure 1: Down-section NBP01-01, AA-186, and KROCK core lithology and normalized magnetic susceptibility data ............................................................... 22 Extended Data Figure 2: Uncorrected Beryllium-10 concentration (10Be), Total Organic Carbon (TOC), and δ13C for NBP01-01 cores ............................................................. 23 ! iv ABSTRACT Ongoing retreat of Antarctica’s marine-based glaciers is associated with warm (~2° C) modified Circumpolar Deep Water intrusion onto the continental shelf, suggesting that Southern Ocean temperatures may influence Antarctic ice sheet stability. Understanding past cryosphere response to environmental forcing is crucial to modeling future ice sheet behavior. Of particular interest is the response of the East Antarctic Ice Sheet (EAIS), which stands to contribute ~20 m to global sea level.
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