Quaternary Stratigraphy of the Northwind Ridge, Arctic Ocean THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Kevin Allen Crawford B.S. Graduate Program in Geological Sciences The Ohio State University 2010 Master's Examination Committee: Peter-Noel Webb, Advisor Leonid Polyak Lawrence A. Krissek Copyright by Kevin A Crawford 2010 Abstract The Arctic Ocean plays an important role in modulating the world‘s climate. Changes in sea-ice albedo and the export of freshwater into the North Atlantic could have serious repercussions to the climate patterns far beyond the Arctic. To understand fully the impacts of the retreating sea-ice cover and the warming Arctic Ocean we need to look into the past for clues. Paleoenvironments of the Arctic Ocean can be reconstructed by using sea-floor sediment constituents, such as paleobiological and mineral components as well as chemical and paleomagnetic parameters. Three cores raised from the Northwind Ridge, north of the Alaskan continental margin, were chosen to investigate sedimentary patterns and related paleoenvironments in the western Arctic Ocean across a time frame from the Holocene to estimated early Pleistocene. These cores show a range of sedimentation rates decreasing from south to north, thus allowing a development of a relatively high-resolution Upper Quaternary stratigraphy at the southern part of the ridge and a lower-resolution, yet longer stratigraphy for its northern part. In addition to this long stratigraphic coverage, the northern core has well-preserved calcareous microfauna, which provides new insights into paleoceanographic environments. All stratigraphic intervals recovered display glacial-interglacial cyclicity expressed in abundances of foraminifera and ice-rafted debris, and variability in stable-isotopic compositions and some chemical elements such as manganese consistent with data from other parts of the ii Arctic Ocean. In addition to this cyclicity, sedimentary and micropaleontological data from cores under study indicate a step increase in glacial inputs and sea-ice coverage at the end of the Early Pleistocene, co-occurring with a fundamental reorganization of the Earth‘s climate during the Mid-Pleistocene Transition. The causal relationships between these processes are yet to be investigated. iii Acknowledgments I would like to thank Dr. Leonid Polyak for working with me on this project and for many discussions concerning the data and interpretations needed for this study. Also I would like to thank Rachel Gray and Tracie Kline for help in processing the samples and Julie Codispoti for encouragement and patience during the writing of this thesis. iv Vita Kevin Allen Crawford March 18, 1970 ..............................................Born – Columbus, Ohio 2004-2008 ......................................................B.S. Geology, The Ohio State University 2008-2010…………………..Graduate Research Associate, The Ohio State University Publications Adler, R.,Polyak, L., Ortiz, J.D., Kaufman, D.S., Channell, J.E.T., Xuan, C., Grottoli, A. G., Sellen, E., and Crawford, K.A., 2009. Sediment record from the western Arctic Ocean with an improved Late Quaternary age resolution: HOTRAX core HLY0503-8JPC, Mendeleev Ridge. Global and Planetary Change, 68, 18 – 29. Yurco, L.N., Ortiz, J.D., Polyak, L., Darby, D.A., Crawford, K.A., 2010. Clay mineral cycles identified by diffuse spectral reflectance in Quaternary sediments from the Northwind Ridge: implications for glacial-interglacial sedimentation patterns in the Arctic Ocean. Polar Research, v 29, issue 2, pp. 176-197. Fields of Study Major Field: Geological Sciences v Table of Contents Abstract ............................................................................................................................... ii Vita ...................................................................................................................................... v Publications ......................................................................................................................... v Fields of Study .................................................................................................................... v List of Tables ................................................................................................................... viii List of Figures .................................................................................................................... ix Introduction ......................................................................................................................... 1 1.1: Physiography ........................................................................................................... 5 1.2: Water masses and circulation .................................................................................. 7 1.3: Biology .................................................................................................................... 9 2.1: Lithostratigraphy .................................................................................................. 11 2.2: Biostratigraphy ...................................................................................................... 13 2.3: Age Control ........................................................................................................... 17 Chapter 3: Materials and Methods ................................................................................... 20 Chapter 4: Northwind Ridge Cores.................................................................................. 23 4.1: Core P1-92AR-P25 ............................................................................................... 25 4.2: Core P1-92AR-P39 ............................................................................................... 32 4.3: Core P1-93AR-P23 ............................................................................................... 38 Chapter 5: Foraminifera ................................................................................................... 43 5.1: Core P1-92AR-P25 ............................................................................................... 43 5.2: Cores P1-92AR-P23 and P1-93AR-P39 ............................................................... 49 Chapter 6: Stable isotopes ................................................................................................ 55 Chapter 7: Stratigraphic correlation and age model ........................................................ 59 7.1: Paleomagnetic Inclination ..................................................................................... 60 vi 7.2: Coarse grain size ................................................................................................... 61 7.3: PW layers and calcium content ............................................................................. 64 7.4: Sediment color and manganese content ................................................................ 66 7.5: Age control ............................................................................................................. 68 Chapter 9: Conclusions .................................................................................................... 78 Appendix A: Faunal Reference List ................................................................................. 80 Appendix B: P1-92AR-P25 Data Table ............................................................................ 83 Appendix C: P1-92AR-P39 Data Table ............................................................................ 88 Appendix D: P1-93AR-P39 Data...................................................................................... 91 Appendix E: P1-92AR-P39 and P1-93AR-P23 Stable Isotope Data ................................ 93 List of References ............................................................................................................. 97 vii List of Tables Table 1: Core location, depth and length recovered ......................................................... 24 Table 2: P1-92AR-P25 Data……………………………………………………………..84 Table 3: P1-92AR-P39 Data……………………………………………………………..88 Table 4: P1-93AR-P23 Data……………………………………………………………..92 Table 5: P1-92AR-P39 and P1-92AR-P23 Stable Isotope Data…………………………94 viii List of Figures Figure Page 1. Index map of the Arctic Ocean showing core sites used in the paper: red circles are P1-92/93-AR cores under study, grey circles are cores from published data, yellow diamond – Beaufort-Mackenzie wells. LR, MR, AR, and NR are Lomonosov, Mendeleev, Alpha, and Northwind ridges, respectively; FS—Fram Strait. Colored arrows show major circulation features: Beaufort Gyre, Transpolar Drift, and Atlantic-water inflow (dashed arrows for subsurface current). Base map is the International Bathymetric Chart of the Arctic Ocean (IBCAO-2; Jakobsson et al., 2008). Dotted lines show the maximal limit of Late Pleistocene glaciations (Dyke et al., 2002; Svendsen et al., 2004), and white arrows show major ice streams at the northern Laurentide margin (Stokes et al., 2005, 2006; Kleman and Glasser, 2007). Semitransparent pink fill in the Canadian Archipelago shows the major source area for dolomitic detrital carbonates in the western Arctic Ocean ..................................... 4 2. Neogloboquadrina pachyderma Left-coiled specimen, umbilical view, scale bar 0.1 mm. http://bprc.osu.edu/foram/species/neogloboquadrina_pach.htm