PALEOECOLOGY OF BERINGIAN LACUSTRINE DEPOSITS AS INDICATED BY NORTHERN HEMISPHERE OSTRACODE BIOGEOGRAPHY A thesis submitted to Kent State University in partial fulfillment of the requirements for the degree of Master of Science by Kathryn J. Wells December 2011 Thesis written by Kathryn J. Wells B.A., Kent State University, 2007 M.S., Kent State University, 2011 Approved by ___________________________________, Advisor Dr. Alison J. Smith ___________________________________, Chair, Department of Geology Dr. Daniel Holm ___________________________________, Dean, College of Arts and Sciences Dr. John R.D. Stalvey ii TABLE OF CONTENTS TABLE OF CONTENTS ................................................................................................... iii LIST OF FIGURES ............................................................................................................ v LIST OF TABLES ............................................................................................................ vii ACKNOWLEDGEMENTS ............................................................................................. viii ABSTRACT ....................................................................................................................... xi Introduction ......................................................................................................................... 1 Background ......................................................................................................................... 5 Location .......................................................................................................................... 5 Regional Geology ........................................................................................................... 8 Study Proxies ................................................................................................................ 12 Regional Paleoecology of Beringia during the Late-Glacial ............................................ 13 Pollen ............................................................................................................................ 14 Insects (Beetles and Chironomids) ............................................................................... 16 Ostracodes ..................................................................................................................... 18 Methods............................................................................................................................. 20 Lab Work ...................................................................................................................... 21 Statistical Analysis ........................................................................................................ 23 Principal Component Analysis (PCA) – Spectral Reflectance .................................. 24 Principal Component Analysis (PCA) - Ostracodes.................................................. 26 iii Cluster Analysis ......................................................................................................... 27 Modern Analog Technique ........................................................................................ 27 Results ............................................................................................................................... 29 Ostracode Assemblages ................................................................................................ 29 Pteroloxa cumuloidea and Candona rectangulata Assemblage ............................... 37 Ilyocypris biplicata and Limnocythere inopinata Assemblage ................................. 44 Cytherissa lacustris Assemblage ............................................................................... 50 Cyclocypris cf. ampla Assemblage ............................................................................ 53 Spectral Reflectance (PCA) .......................................................................................... 56 Ostracodes (PCA) ......................................................................................................... 65 Cluster Analysis ............................................................................................................ 74 Modern Analog Reconstruction .................................................................................... 77 Ostracode Zonation ....................................................................................................... 81 Discussion ......................................................................................................................... 83 Conclusions ....................................................................................................................... 93 References ......................................................................................................................... 96 Appendix A: USGS 70-92 Sample Inventory ................................................................. 114 iv LIST OF FIGURES Figure 1. Map of Beringia. .................................................................................................. 2 Figure 2. Late Pleistocene glaciation in Beringia. .............................................................. 3 Figure 3. USGS 70-92 Location in northeastern Chukchi Sea. ......................................... 7 Figure 4. USGS 70-92 Stratigraphic Column. .................................................................... 9 Figure 5. Vibracore Locations in the northeastern Chukchi Sea. ..................................... 10 Figure 6. Tectonic Setting of the Chukchi Shelf. .............................................................. 11 Figure 7. Relief map of Beringia region. .......................................................................... 14 Figure 8. Tree macrofossils found on West and East Beringia ......................................... 16 Figure 9. USGS 70-92 Ostracode Abundance & Zonation. .............................................. 33 Figure 10. USGS 70-92 Ostracode Abundance & Zonation, Expanded........................... 34 Figure 11. USGS 70-92 Common Ostracode Species ...................................................... 36 Figure 12. Map of Pteroloxa cumuloidea ......................................................................... 40 Figure 13. Map of Candona rectangulata ........................................................................ 42 Figure 14. Map of Ilyocypris biplicata ............................................................................. 46 Figure 15. Map of Limnocythere inopinata. ..................................................................... 48 Figure 16. Map of Cytherissa lacustris............................................................................. 52 Figure 17. Map of Cyclocypris cf. ampla ......................................................................... 55 Figure 18. Spectral Reflectance Scree Plot from SPSS®. ................................................ 57 Figure 19. VPC_1 Spectral Graph. ................................................................................... 59 Figure 20. VPC_2 Spectral Graph. ................................................................................... 60 v Figure 21. VPC_3 Spectral Graph. ................................................................................... 61 Figure 22. VPC_4 Spectral Graph. ................................................................................... 62 Figure 23. Downcore Reflectance Scores and Ostracode Abundance. ............................. 63 Figure 24. VPC_4 from USGS 70-92 vs. VPC_1 from Regional Data. ........................... 64 Figure 25. PCA Graph for Ostracodes (Axis 1 vs. 3) ....................................................... 68 Figure 26. PCA Graph for Ostracodes (Axis 1 vs. 2) ....................................................... 70 Figure 27. PCA Graph for Ostracodes and Spectral Reflectance (Axis 1 vs. 2) .............. 72 Figure 28. Cluster Dendrogram. ....................................................................................... 76 Figure 29. Modern Analog Map. ...................................................................................... 80 Figure 30. Relationship between Cytherissa, Candona, & Limnocythere. ....................... 84 Figure 31. Distribution of Illite. ........................................................................................ 88 Figure 32. Clay Provinces of the Arctic. ........................................................................... 88 Figure 33. NGRIP δ18O Record with Downcore Reflectance Scores ............................... 91 Figure 34. Warm Arctic – Cold Continent Climate Pattern.............................................. 92 Figure 35. Bering Land Bridge Region............................................................................. 95 vi LIST OF TABLES Table 1. Non-Ostracode Material in USGS 70-92. ........................................................... 31 Table 2. USGS 70-92 Species Table with References. ..................................................... 32 Table 3. Table to Accompany Figure 11 .......................................................................... 35 Table 4. Pteroloxa cumuloidea and Candona rectangulata Assemblage ......................... 39 Table 5. Ilyocypris biplicata and Limnocythere inopinata Assemblage ........................... 45 Table 6. Cytherissa lacustris Assemblage .......................................................................