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Copyright Rebecca Lynn Minzoni 2015 ABSTRACT The Antarctic Peninsula’s Response to Holocene Climate Variability: Controls on Glacial Stability and Implications for Future Change By Rebecca Lynn Minzoni The Antarctic Peninsula is one of the most rapidly changing regions in the cryosphere, with 87% of its glaciers receding and several ice shelves catastrophically collapsing since observations began in the 1960’s. These substantial, well-documented changes in the ice landscape have caused concern for the mass balance of the Antarctic Peninsula Ice Cap. To better understand the significance of these recent changes, I have assimilated a massive database of new and published marine sedimentary records spanning the Holocene Epoch (the last 11.5 kyrs). The database includes 9 coastal embayments with expanded sedimentary packages and well-dated cores. Each site represents an end-member in the wide range of Antarctic Peninsula oceanography, orography, meteorology, and glacial drainage basin characteristics. Multi-proxy analysis, including sedimentology, geochemistry, and micropaleontology, was conducted at each site to reconstruct glacial history at centennial-scale resolution, on par with ice-core data. The coastal sites were then compared in the context of published ice-core paleoclimate, paleoceanographic, and glaciological records. The first of these sites, Herbert Sound, provides an unparalleled opportunity to compare the marine sediment record with a related ice-core in an Antarctic maritime setting. Herbert Sound is the southernmost embayment studied on the eastern side of the Antarctic Peninsula and represents an end-member with a cold, dry atmosphere and cold, saline ocean mass. The record from Herbert Sound indicates grounded ice receded quickly and early in the Holocene, followed by a floating ice phase that collapsed 10 2.4 calendar kyrs before present (cal kyr BP, where present day is 1950 A.D.) and never re-advanced. The fjord remained open and productive during the prolonged warm intervals of the Mid Holocene, and began to experience greater glacial influence and sea ice cover during Late Holocene cooling, a period termed the Neoglacial. The second site, Ferrero Bay of the Amundsen Sea, is the southernmost end-member on the western side of the Antarctic Peninsula and represents a truly polar coastal setting. Grounded ice receded from the deep basin much earlier than expected, ~10.7 cal kyr BP, likely due to advecting water masses that under-melted the extended ice sheet. Ferrero Bay was then covered by the extensive Cosgrove Ice Shelf, which remained stable during the Mid Holocene Hypsithermal despite incursion of warm water, and did not recede to its current position until 2.0 cal kyr BP, coincident with Neoglacial cooling. Thus, Ferrero Bay and the Cosgrove Ice Shelf were out of phase with the northern peninsula sites and apparently were not sensitive to Holocene climate variability but rather to impinging warm ocean currents, which are observed in Ferrero Bay today. Comparison of 9 coastal sites, including Herbert Sound, Ferrero Bay, and several other embayments of various local settings, shows highly variable glacial response to Early Holocene warming, with difference in onset of 4.2 kyrs and difference in duration of 2.5 kyrs. The Mid Holocene more synchronous, with a difference in the onset of 1.7 kyrs and a difference in duration of 1.9 kyrs. The Late Holocene Neoglacial by contrast was highly synchronous with difference in onset and duration of 0.7 kyrs and 0.7 kyrs, respectively. Later historic events of shorter duration, such as the Little Ice Age, were more synchronous with difference in onset and duration of 0.3 kyrs and 0.2 kyrs, respectively. Regional glacial behavior became more synchronous during the Holocene as the glaciers and their drainage basins became progressively smaller, rendering them more sensitive to climate change and less influenced by local forcings such as ocean temperature, basin bathymetry, and precipitation effects. This increase in glacier sensitivity helps explain the current widespread glacial recession in response to the rapid regional warming of ~3.5 C over the last century. Acknowledgments First and foremost I am grateful to Dr. John Anderson for the numerous opportunities and challenges he has given me during this PhD. The research included in this dissertation was shaped by several enriching experiences that John facilitated, including my attendance to workshops around the globe to learn new skills, namely diatom micropaleontology. It takes a truly altruistic advisor to allow a student to pursue what might be considered tertiary interests to a project. John had the confidence in me to bring these various pursuits together into a holistic, large-scale analysis; fortunately, these external pursuits became the key proxies for our interpretations. I could not dream of a more exciting and fulfilling PhD experience. Thank you, John, for believing in me, for investing in me, and for growing me into a more confident and mature scientist. I thank my committee members for investing countless hours and resources into my professional development. Thank you, Dr. André Droxler, for being a reliable sounding board for ideas, for allowing me to use your lab space with an open door policy, and for being an excellent teacher in the classroom and in the field. Thank you, Dr. Jeffrey Nittrouer, for constructive feedback and lively lab discussions. Thank you, Dr. Volker Rudolf, for serving as a mentor who truly has students’ best interest in mind. I would like to especially thank Dr. Julia Wellner, who acted as a committee member in every sense of the word. Julia, you have been an excellent co- author, friend, and role model to me. I appreciate you incorporating me into your lab group at UH and facilitating collaboration and progressive thinking in our research. I also thank Dr. Amy Leventer (Colgate) who has been an exceptionally generous mentor to me in diatomology and in Antarctic field science, and a key supporter in my pursuit of micropaleontology. Thank you for connecting me with the welcoming community of the Polar Marine Diatom Workshops and teaching me skills that were essential to this research. v Thank you to my ever-supportive, high-spirited co-authors, Dr. Rodrigo Fernandez, Dr. Wojciech Majewski, Dr. Yusuke Yokoyama, and Dr. Martin Jakobsson. This research builds upon three decades of hard work at sea in harsh conditions, as well as countless hours in the laboratory by dedicated scientists and technicians. I thank the crews of Oden Southern Ocean Cruise 09-10, Nathaniel B. Palmer cruises 05-02 and 07-03, Polar Duke 1990 and 1991, and Deep Freeze (USCG Glacier) 1982. Thank you to Dr. Charlotte Sjunneskog and Steve Petrushak for their assistance with sampling and data collection at the Antarctic Research Facility. Thank you to Dr. Tony Gary and TACSWorks for teaching me Fuzzy C-Means analysis and graciously allowing me to use their software for this project. Thank you to Dr. Caroline Masiello for allowing me to use her lab and advising me on geochemical methods. This work was completed with funding from the National Science Foundation Award OPP99-09734 to John B. Anderson and Julia S. Wellner, and OPP0837925 to John B. Anderson. This research was also facilitated by the Douglas and Martha Lou Broussard Fellowship and travel grants from Rice University, the Scientific Committee on Antarctic Research, PAGES, and the International Symposium of Antarctic Earth Science through NSF. Martha Lou Broussard, you have created a legacy for students of the Earth Science Department that constantly inspires me; you are the model example of how alumni should give back to the community that shaped them. Thank you. I am exceptionally grateful to Dr. Luis González (KU), the late Dr. Larry Martin (KU), and Dr. Kraig Derstler (UNO) for their openhanded, enthusiastic mentorship and for their belief in my early dreams of pursuing the noble, ever-evolving path of a research scientist. I am especially grateful to Ruthie Halberstadt, Catherine Ross, Victoria Yuan, Kelsey Crocker, and Savannah Ezelle for working with me in the lab and for their unbridled enthusiasm, which served as motivation for me during PhD doldrums. The support of my peers has been essential to my progress at Rice. Thank you Dr. Lauren Simkins, Lindsay Prothro, Yuribia Munoz, Brian Demet, Dr. Davin vi Wallace, Travis Stolldorf, Karem Lopez, Dr. Lizette Leon-Rodriguez, Svetlana Burris, Dr. Xiaodong Gao, Krystle Hodge, Stacy Dwyer, Sarah Huff, Lily Seidman, Kaitlyn Moran, Tian Dong, Laura Carter, Jen Gabler, Dr. Lester King, Shibu Mathukutty, Ayca Agar Cetin, Dr. Brandon Harper, Clint Miller, Dr. Ananya Malik, Dr. Pranabendu Moitra, Dr. Matt Weller, Jacob Seigel, Dr. Ben Slotnik, and Pankaj Khanna. Many heart-felt thanks to the gracious ESCI administrators who were always available and encouraging to me, despite their busy schedules: Mary Ann Lebar, Soookie Sanchez, Sandra Flechsig, Roger Romero, Pat Jordan, and Lee Wilson. I also thank Dr. Malcolm Ross, Dr. Albert Bally, Dr. Steve Bergman, and Dr. James Eldrett for their mentorship and support at Shell and beyond. Much like a healthy carbonate platform, my family has been the framework upon which my academic life was able to grow and mature. Thank you, Dr. Marcello Minzoni, my brilliant and ardent husband, who served in the trenches, picking up the slack at home when I needed to put extra hours into my research, and ultimately for understanding the joy and the challenge of completing a PhD. Thank you for being a loving, involved father to our beautiful boys and for consistently helping me see the big picture of what is most important in life. I thank my supportive siblings, Nate, Louise, Matt, Cody, and Wyatt, for their interest in my research, and for always understanding when I missed events due to field excursions and writing deadlines. I also thank Dr.

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