City University of New York (CUNY) CUNY Academic Works All Dissertations, Theses, and Capstone Projects Dissertations, Theses, and Capstone Projects 5-2015 The State of the Oligocene Icehouse World: Sedimentology, Provenance, and Stable Isotopes of Marine Sediments from the Antarctic Continental Margin Daniel William Hauptvogel Graduate Center, City University of New York How does access to this work benefit ou?y Let us know! More information about this work at: https://academicworks.cuny.edu/gc_etds/966 Discover additional works at: https://academicworks.cuny.edu This work is made publicly available by the City University of New York (CUNY). Contact: [email protected] THE STATE OF THE OLIGOCENE ICEHOUSE WORLD: SEDIMENTOLOGY, PROVENANCE, AND STABLE ISOTOPES OF MARINE SEDIMENTS FROM THE ANTARCTIC CONTINENTAL MARGIN by DANIEL W. HAUPTVOGEL A dissertation submitted to the Graduate Faculty in Earth and Environmental Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy, The City University of New York 2015 © 2015 Daniel W. Hauptvogel All Rights Reserved ii This manuscript has been read and accepted for the Graduate Faculty in Earth and Environmental Sciences in satisfaction of the dissertation requirement for the degree of Doctor of Philosophy. Dr. Stephen F. Pekar Date Chair of Examining Committee Dr. Cindy Katz Date Executive Officer Athanasios Koutavas Cecilia M. Mchugh Trevor Williams Sidney R. Hemming Supervisory Committee THE CITY UNIVERSITY OF NEW YORK iii Abstract The State of the Oligocene Icehouse World: Sedimentology, Provenance, and Stable Isotopes of Marine Sediments from the Antarctic Continental Margin by Daniel W. Hauptvogel Adviser: Dr. Stephen F. Pekar Abstract The Oligocene Epoch (34-23 Ma) was a dynamic time in Antarctica, with previous ice volume estimates suggesting fluctuations from below 50 % up to 140 % of modern all while atmospheric CO2 decreased from above 1,000 ppm in the Early Oligocene to near modern levels by the Late Oligocene. Most of what is known about the Oligocene Antarctic cryosphere however, is derived from distal sedimentary records that can only provide a generalized view of the cryospheric dynamics in Antarctica. To better understand regional differences in Antarctic glacial dynamics, proximal records are needed. This dissertation advances our understanding of these dynamics in Antarctica during the Oligocene by investigating three proximal, marine sediment cores from different regions of the continent. Ice-rafted debris (IRD) concentrations, 40Ar/39Ar thermochronology, and stable isotope records combined from 3 proximal marine sediment cores reveal a large ice sheet existed throughout the Oligocene, with ice volume reaching up to 155 % of modern. Concentrations and 40Ar/39Ar thermochronology from IRD offshore of the Wilkes subglacial basin suggest the ice sheet was fairly stable on elevated portions such as the Adélie Craton, but the basin itself was more responsive to climate changes. These changes appear to be influenced by 405-kyr iv eccentricity and 1.2 myr obliquity. In the Ross Sea, 40Ar/39Ar thermochronology from IRD show a large West Antarctic influence, indicative of a large ice sheet residing there during the Late Oligocene. Stable isotopes from benthic foraminifera from the Maud Rise show ice volume fluctuations from below 50 % up to 155 % of modern, in agreement with modeling and far-field records. The isotope record is also influenced by 405-kyr and 100-kry eccentricity and does not show a warming trend during the Late Oligocene as seen in other isotope records. Together, these records are indicative of a near-modern size or larger ice sheet present in both East and West Antarctica during the Oligocene, a time when the extent of Antarctica glaciation has been debated. v Acknowledgements I would like to thank my Ph.D. advisor, Dr. Stephen F. Pekar, for his guidance, support, and allowing me the independence for completing this dissertation. He has been a mentor and has provided several opportunities for me over the past 4 years. Dr. Sidney Hemming and Dr. Trevor Williams have been indispensible over the course of this research. Their knowledge and encouragement are one of the many reasons I have made it this far and I thank them for serving on my dissertation committee. I would also like to thank Dr. Athanasios (Tom) Koutavas and Dr. Cecilia McHugh for serving on my dissertation committee. A special thanks to Dr. Allan Ludman for always being someone to talk to and seek advice from, especially for my post-graduate future. To my wife Christine, who has put up with me through my years of graduate school and has always supported me in my endeavors. Sitting at a desk all day can become tedious, and I thank my office/lab-mate Matt for being there to keep me sane for the first 3 years of research. You are a good friend and I wish you all the luck in the future. I would like to thank my mother, father, and the rest of my family for always believing in me and supporting me throughout my academic career. Lastly I would not be where I am today if it weren’t for the encouragement of my high school chemistry and physics teacher, Joseph Fusco, whom truly opened my eyes to science. vi Table of Contents Chapter 1. An Introduction to Antarctica and the Oligocene ................................................ 1 1.1 Geologic History of Antarctica .............................................................................................. 3 1.2 The Early Icehouse World ................................................................................................... 10 1.2.1 Trend in Cenozoic Climate ............................................................................................ 11 1.2.3 Climate History of the Oligocene ................................................................................. 14 1.3 Ice-rafted debris history ....................................................................................................... 21 1.4 Use of 40Ar/39Ar in Ice-rafted Debris ................................................................................... 24 1.5 Previous Drilling Expeditions and Proximal Antarctic Records .......................................... 26 1.6 Questions addressed by this study ........................................................................................ 30 1.7 Significance .......................................................................................................................... 32 Chapter 2. Evidence for large East Antarctic Ice Sheet in the Wilkes Subglacial Basin during the Oligocene ................................................................................................................... 33 2.1 Introduction .......................................................................................................................... 34 2.1.1 The Wilkes Sub-glacial Basin ....................................................................................... 34 2.1.2 Lithostratigraphy of the Oligocene section at Site U1356 ........................................... 36 2.1.3 Regional geology of the WSB region ............................................................................ 40 2.1.4 Previous studies in the WSB region .............................................................................. 43 2.2 Methods ................................................................................................................................ 45 2.2.1 Sampling ....................................................................................................................... 45 2.2.2 Sediment Separation ..................................................................................................... 47 2.2.3 IRD concentrations ....................................................................................................... 48 2.2.4 40Ar/39Ar Thermochronology ........................................................................................ 48 vii 2.3 Results .................................................................................................................................. 50 2.4 Discussion ............................................................................................................................ 54 2.4.1 Implications for ice volume during the Oligocene ........................................................ 54 2.4.2 Gravity Flows: Evidence for a larger than modern ice sheet ....................................... 60 2.4.3 Ar Thermochronology .................................................................................................... 61 2.4.4 Hornblende vs. Biotite as a provenance signal ............................................................. 64 2.4.5 Small biotite vs. large biotite ......................................................................................... 66 2.4.6 Age distribution in the high IRD bearing layers ........................................................... 67 2.4.7 Age distribution in the low IRD abundance intervals ................................................... 69 2.4.8 Age Distribution of the Debris Flow Layers ................................................................. 71 2.4.9 Sediment Transport during the Late Oligocene ............................................................. 73 2.4.10 Implications for ice sheet changes the Oligocene ....................................................... 74 2.5 Conclusion ...........................................................................................................................