UNIVERSITY of CALIFORNIA, SAN DIEGO Seasonal Precipitation at a 3.97 Ma Australopithecus Anamensis Site, Allia Bay, Kenya A
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UNIVERSITY OF CALIFORNIA, SAN DIEGO Seasonal precipitation at a 3.97 Ma Australopithecus anamensis site, Allia Bay, Kenya A dissertation submitted in partial satisfaction of the requirements for the degree Doctor of Philosophy in Anthropology with a Specialization in Anthropogeny by Melanie M. Beasley Committee in charge: Professor Margaret J. Schoeninger, Chair Professor Carolyn M. Kurle Professor Thomas E. Levy Professor Joanna M. McKittrick Professor Katerina Semendeferi 2016 Copyright Melanie M. Beasley, 2016 All rights reserved The Dissertation of Melanie M. Beasley is approved and it is acceptable in quality and form for publication on microfilm and electronically: ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ ____________________________________________________________ Chair University of California, San Diego 2016 iii DEDICATION For the man who taught me to love teaching and was a huge supporter of my education: Turhon A. Murad, PhD, ABFA (July 27, 1944 – August 15, 2015) Mentor, adopted father, and gingerbread house builder. iv TABLE OF CONTENTS SIGNATURE PAGE…………………………………………………………………... iii DEDICATION………………………………………………………………………… iv TABLE OF CONTENTS……………………………………………………………… v LIST OF FIGURES …………………………………………………………………... xiii LIST OF TABLES …………………………………………………………………… ix ACKNOWLEDGMENTS …………………………………………………………… x CURRICULUM VITAE ……………………………………………………………... xv ABSTRACT OF THE DISSERTATION ……………………………………………. xvii CHAPTER 1: INTRODUCTION ……………………………………………………. 1 References…………………………………………………………………… 6 CHAPTER 2: MIOMBO WOODLANDS AND EARLY HOMININS: A COMPARISON OF CARBONATE STABLE ISOTOPE FAUNAL DATA FROM MODERN KOOBI FORA AND 3.97MA ALLIA BAY, EAST LAKE TURKANA, KENYA………………………………………………………… 9 Introduction…………………………………………………………………. 9 Paleoenviornmental reconstruction of the Omo-Turkana Basin…………… 16 Principles of stable isotope analysis………………………………………… 18 Oxygen ……………………………………………………………… 18 Carbon ……………………………………………………………... 20 Materials and methods………………………………………………………. 22 Fossil sample ……………………………………………………….. 22 Modern sample ……………………………………………………... 23 Laboratory preparation ……………………………………………. 24 Statistical analysis …………………………………………………. 25 Results ………………………………………………………………………. 25 Comparison with pilot study ……………………………………….. 25 Paleolandscape at Allia Bay ……………………………………...... 26 Allia Bay vs. Kanapoi and Omo Mursi …………………………….. 28 Discussion …………………………………………………………………... 29 Hippopotamidae-Giraffidae offset ………………………………… 29 Omo-Turkana Basin 4.2 to 3.9 MA ………………………………… 30 Reconstructing mosaic habitats and Au. anamensis ………………. 32 v Conclusion ………………………………………………………………..... 34 Acknowledgments …………………………………………………………. 35 References…………………………………………………………………. 53 CHAPTER 3: DIAGENESIS OF FOSSIL TOOTH ENAMEL: FLUORESCENCE AND SECONDARY ION MASS SPECTROMETRY (SIMS) REVEAL ALTERED MINERAL STRUCTURE AFFECTS δ18 O VALUES IN FAUNAL ENAMEL ………………………………………….... 64 Introduction………………………………………………………………… 64 Fossilization and diagenesis of biological material ……………………….. 67 18 High-resolution δ Oen values generated by SIMS ………………………… 68 Fluorescence in teeth ………………………………………………………. 69 Imaging fossil teeth to identify diagenesis ………………………………… 71 Models of diagenesis: Expectations for SIMS and CLFM analysis ……… 73 Materials and Methods ……………………………………………………. 73 Modern Sample ……………………………………………………. 73 Fossil Sample……………………………………………………….. 74 Sample preparation, confocal laser fluorescent microscopy (CLFM) ………………………………………………. 75 Secondary ion mass spectrometry (SIMS) ………………………... 76 Sample pit quality evaluation …………………………………….. 78 Results and Discussion …………………………………………………….. 79 Modern Koobi Fora fauna: SIMS and recording seasonal shifts in δ18 O …………………………………………….. 79 CLFM images and diagenesis …………………………………..… 80 Diagenesis not identified by CLFM images ………………………. 82 Conclusion …………………………………………………………………. 84 Acknowledgements ………………………………………………………... 84 References………………………………………………………………….. 134 CHAPTER 4: SEASONALITY AND ADAPTIVE FLEXIBILITY IN EARLY HOMININS AT ALLIA BAY, KENYA 3.97 MA …….............................. 142 Introduction…………………………………………………………….…... 142 Hominin evolution and paleoenvironment reconstructions ……………….. 146 Mosaic habitats and Au.anamensis ………………………………………… 148 East Africa paleoclimate …………………………………………………… 152 vi Stable oxygen isotopes and precipitation ……………………...…………… 154 Temporal resolution of enamel sampling ……………...…………... 158 High-resolution δ18 O values generated by SIMS …………………... 160 Paleoprecipitation predictions ……………………..……………… 162 Materials and methods ……………………………………………………… 163 Fossil sample ……………………………………………………….. 163 Sample preparation, confocal laser fluorescent microscopy (CLFM) ……………………………………………….... 164 Secondary ion mass spectrometry (SIMS) ………………………….. 165 SIMS pit quality evaluation and assessment of diagenesis ………… 166 Results and Discussion ………………………………………………………. 167 Variation in δ18 O across a tooth ……………………………………. 168 Establishing the baseline of the δ18 O ecosystem: Hippopotamidae ……………………………………………………. 170 Browser δ18 O paleoseasonality signal: Gradual change under stable and fluctuating conditions …………………………………… 172 Grazer δ18 O paleoseasonality signal: Abrupt shifts within relatively stable conditions …………………………………………. 174 Paleoseasonality at Allia Bay ………………………………………. 176 Conclusion …………………………………………………………………… 179 Acknowledgements ………………………………………………………….. 180 References……………………………………………………………………. 241 CHAPTER 5: DISCUSSION AND CONCLUSION .……………………………….. 254 Future studies ………………………………………………………………… 255 SIMS analysis of δ13 C …………………………………………….. 255 Australopithecus anamensis fossil localities ………………………. 256 Other fossil localities …………………………………………….… 257 Diagenesis and CLFM image fluorescence ……………………….. 258 Conclusion ………………………………………………………………….. 259 References ………………………………………………………………...… 260 vii LIST OF FIGURES Figure 2.1. Map of the Omo-Turkana Basin highlighting fossil localities .………….. 36 Figure 2.2. Map of the Omo-Turkana Basin. …….………………………………….. 37 Figure 2.3. Scatterplot of δ13 C and δ18 O of modern Koobi Fora and Allia Bay fauna ………………………………………………………….…. 38 Figure 2.4. Scatterplot of δ13 C and δ18 O of Allia Bay, Omo Mursi, and Kanapoi fauna ……………………………………………………….……... 39 13 Figure 2.5. Plot of mean annual precipitation (MAP) vs. δ Cenamel ……………….... 40 Figure 3.1. Transmitted light and cathodoluminescence images of enamel………... 85 Figure 3.2. Comparison of three imaging methods of a fossil Suidae sample from Allia Bay …………………………………………….……………….. 86 Figure 3.3. Comparison of CLFM three laser line images …………………………. 87 Figure 3.4. Modern and fossil enamel CLFM green fluorophore images ………….. 88 Figure 3.5. CLFM laser line images of a SIMS transect ………………………….... 89 Figure 3.6. SEM images of SIMS analysis pits ……………………………………. 90 Figure 3.7. Plot of modern fauna SIMS δ18 O transect …………………………….... 91 Figure 3.8. Comparison of fluorophores in SIMS transect for Elephantidae………. 92 Figure 3.9. Comparison of fluorophores in SIMS transect for Giraffidae………..… 93 Figure 3.10. Plot of Elephantidae SIMS (4901.2) δ18 O transect………………….… 94 Figure 3.11. Plot of Giraffidae (4860.1) SIMS δ18 O transect……….……………… 95 Figure 3.12. Comparison of fluorophores in SIMS transect for Deinotheriidae …… 96 Figure 3.13. Plot of Deinotheriidae (4857.1) SIMS δ18 O transect …………..…….. 97 Figure 3.14. Plot of Giraffidae (4859b3) SIMS δ18 O transect ……………………... 98 Figure 3.15. Plot of Elephantidae (4908a3) SIMS δ18 O transect ………………….. 99 Figure 3.16. Images of unique enamel inclusion in Giraffidae (4859b3) Line 3 …. 100 Figure 4.1. Plot of Bovidae (4877) SIMS δ18 O transects ………………………..…. 181 Figure 4.2. Plot of three Hippopotamidae SIMS δ18 O transects ………………….... 182 Figure 4.3. Plot of two Giraffidae SIMS δ18 O transects……………………………. 183 Figure 4.4. Plot of three Proboscidaes SIMS δ18 O transects ………………………. 184 Figure 4.5. Plot of Equidae (4854a4) SIMS δ18 O transects………………………… 185 Figure 4.6. Plot of two Suidae SIMS δ18 O transects ……………………………….. 186 viii LIST OF TABLES Table 2.1. Allia Bay fossil sample sample……. ……………………………………… 41 Table 2.2. Turkana Basin (Koobi Fora) modern species data ………………………… 43 Table 2.3. Comparison of current study Allia Bay fossil fauna to Schoeninger et al. (2003)…………………………………..……………….. 48 Table 2.4. Mann-Whitney U results for modern Koobi Fora compared to fossil Allia Bay fauna…………………………………………………………. 49 Table 2.5. Mann-Whitney U Results for Fossil Locality Comparisons ……….……… 50 Table 2.6. Comparison of Hippopotamidae-Giraffidae offset in East Africa …………. 51 Table 2.7. Mann-Whitney U Results for Hippopotamidae and Giraffidae Comparisons ……………………………………………………….. 52 Table 3.1. Comparison of SIMS δ18 O biogenic range compared to non-biogenic range ………………………………………………………….…. 101 Table 4.1. Comparison of variation in ∆18 O recorded by different serial sampling methods of modern herbivores in Kenya …………………….. 187 Table 4.2. Summary data for Allia Bay fossil samples…………………………………. 188 Table 4.3. Temporal resolution of line transects for Allia Bay fossil samples….……… 189 ix ACKNOWLEDGEMENTS I would like to thank my family, friends and collaborators because without their love and support this dissertation would never have been pursued or completed. First, I am eternally grateful to my advisor and mentor, Margaret Schoeninger, for her guidance, wisdom, patience, and understanding as I battled my through