GEOCHEMICAL FINGERPRINTING OF SPECULAR HEMATITE FROM PREHISTORIC MINES AND ARCHAEOLOGICAL SITES IN SOUTHERN AFRICA by ADAM VICTOR KIEHN (Under the Direction of George A. Brook) ABSTRACT Specularite ore was collected from five prehistoric mining regions in Botswana and the Northern Cape Province of South Africa and 172 samples were analyzed by instrumental neutron activation analysis. A fingerprinting methodology was developed using the geochemical signatures of specularite sources represented by first-row transition metals. A validation set of 15 samples was chosen and underwent the fingerprinting process to test the validity of the method. A deductive elemental limit series analysis reduced the number of possible sources for each validation sample. Discriminant function analysis then correctly classified 14 of 15 validation samples and 6 of 7 specularite artifacts from archaeological sites in Botswana. INDEX WORDS: Specularite, Hematite, Geochemistry, Provenance, Geoarchaeology, INAA GEOCHEMICAL FINGERPRINTING OF SPECULAR HEMATITE FROM PREHISTORIC MINES AND ARCHAEOLOGICAL SITES IN SOUTHERN AFRICA by ADAM VICTOR KIEHN B.S., University of Wisconsin-Madison, 2004 A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE ATHENS, GEORGIA 2008 © 2008 Adam Victor Kiehn All Rights Reserved GEOCHEMICAL FINGERPRINTING OF SPECULAR HEMATITE FROM PREHISTORIC MINES AND ARCHAEOLOGICAL SITES IN SOUTHERN AFRICA by ADAM VICTOR KIEHN Major Professor: George A. Brook Committee: Samuel Swanson Ervan Garrison Electronic Version Approved: Maureen Grasso Dean of the Graduate School The University of Georgia May 2008 DEDICATION I would like to dedicate this thesis to everyone who has helped along the way and given me a push to finally get it finished. My family has been behind me every step of the way to give me the confidence and drive to finish the work, and without their urging this work may not have come to fruition. Whitney, my fiancé, has also stuck with me through all of the lab drudgery that followed the fun fieldwork in Africa in the last 2-plus years, even during her own thesis work while in another state. And, of course, I would not have been able to do any of this without the opportunities, encouragement, advice, and means that George has given to me, even when I've been a "bottleneck" at times in the last 4 years. Thank you. - iv - ACKNOWLEDGEMENTS I would like to acknowledge and say, "Thank you," to the many people and organizations that contributed time, effort, expertise, and funding to make this project successful. Funding was provided from the National Science Foundation to the University of Georgia (#9520982 and #0313826) and the University of Missouri (#0504015). My studies were made possible by assistantships from the University of Georgia Graduate School and Department of Geology. Dr. George Brook, my Major Professor and advisor is responsible for making this project possible and helping in some way at nearly every stage with funding, advice, guidance, motivation and most especially during the six-week trip to Southern Africa to collect all of the specularite samples in 2005. Dr. Sam Swanson and Dr. Ervan Garrison also provided much essential guidance and expertise to my studies and laboratory methods. All of my graduate student colleagues have lent valuable advice and diversions. Fuyuan Liang also gave laboratory help and advice, and Sheldon Skaggs ran my XRD samples and gave me a place to stay on my return trips to Athens when finally finishing this thesis. Michael Glascock, Rachel Popelka-Filcoff, and Jonathan Dake of the University of Missouri granted funding, knowledge, and effort in processing so many samples by INAA. Laboratory space and equipment was provided by Drs. Paul Schroeder and Michael Roden in Dept. of Geology and Dr. David Leigh in the Dept. of Geography at UGA. - v - Eugene Marais provided housing and guidance that made the trip possible and aided an attempt to sample a prehistoric mine in Klein Aus, Namibia. Archaeological and Geologic specularite samples from the Tsodilo Hills and Toteng Site in Botswana were obtained with the help and knowledge of Alec Campbell of Gaborone, Botswana; Larry Robbins of Michigan State University, Mike Murphy of Kalamazoo Valley Community College; Bob Hitchcock of the University of Nebraska-Lincoln; Grace Babutsi and Abel Abednico Mabuse of the University of Botswana; and, of course, George Brook. Alec Campbell also provided housing and guided us to the Sebilong and Dikgatlampi mines near Gaborone. David Morris and Leon Jacobson of the McGregor Museum in Kimberley, South Africa provided archaeological specularite sample MACG-01 and helped us find and obtain permission to sample the Blinkklipkop specularite mine. Catrien Van Waarden housed us while in Francistown, Botswana and guided us to the Matsiloje specularite mine. David R. Cohen of the University of Califronia-Berkeley provided archaeological specularite samples from AK-47 site in Thamaga, Botswana. - vi - TABLE OF CONTENTS ACKNOWLEDGEMENTS........................................................................................................ v LIST OF TABLES .................................................................................................................. viii LIST OF FIGURES.................................................................................................................... v CHAPTER 1 INTRODUCTION........................................................................................... 1 1.1 OBJECTIVES AND ASSUMPTIONS........................................................................ 2 1.2 GLOSSARY ............................................................................................................... 5 1.3 LITERATURE REVIEW............................................................................................ 5 CHAPTER 2 BACKGROUND........................................................................................... 14 2.1 STUDY REGIONS................................................................................................... 14 2.2 GEOLOGY AND ARCHAEOLOGY OF SPECULARITE SOURCES..................... 15 2.3 ARCHAEOLOGICAL SAMPLES............................................................................ 20 CHAPTER 3 METHODOLOGY ........................................................................................ 24 3.1 LABORATORY METHODS.................................................................................... 24 3.2 DATA ANALYSIS................................................................................................... 27 CHAPTER 4 RESULTS AND DISCUSSION .................................................................... 42 4.1 GEOLOGIC CHARACTERIZATION OF SOURCES.............................................. 42 4.2 GEOLOGIC SAMPLES - REGIONAL SOURCES .................................................. 53 4.3 ARCHAEOLOGICAL SAMPLES............................................................................ 74 CHAPTER 5 CONCLUSIONS ........................................................................................... 87 BIBLIOGRAPHY .................................................................................................................... 91 APPENDIX – RAW COMPOSITIONS OF SPECULARITE SAMPLES................................. 97 - vii - LIST OF TABLES Table 1. List of archaeological specularite samples and provenience information ..................... 23 Table 2. Comparison of replicate sample log-ratios before and after heavy mineral concentration. ......................................................................................................................................... 26 Table 3. Minimum detection limits of selected elements for INAA (Popelka-Filcoff, 2006)...... 26 Table 4. Training and Validation sample distribution among specularite sources. .................... 33 Table 5. Raw compositions and summary statistics for five replicate heavy mineral concentrate samples from Dikgatlampi Mine, Botswana as determined by INAA. ............................... 35 Table 6. ALR transformed compositions and summary statistics for five replicate heavy mineral concentrate samples from Dikgatlampi Mine, Botswana. .................................................. 36 Table 7. Brief summary of results of analyses performed on representative source samples. ..... 43 Table 8. Summary of ELS analysis and resulting parameters for DFA trials.............................. 56 Table 9. Geologic Trial 5a Training Sample DFA Classification matrix.................................... 58 Table 10. Canonical discriminant function coefficients for Geologic Trial 5a. .......................... 59 Table 11. Geologic Trial 4a Training Sample DFA Classification matrix.................................. 60 Table 12. Canonical discriminant function coefficients for Geologic Trial 4a. .......................... 60 Table 13. Canonical discriminant function coefficients for Geologic Trial 3a. .......................... 63 Table 14. Geologic Trial 3a Training Sample DFA Classification matrix.................................. 64 Table 15. Geologic Trial 3b Training Sample DFA Classification matrix.................................. 65 Table 16. Canonical discriminant function coefficients for Geologic Trial 3b. .......................... 65 Table 17. Canonical discriminant function coefficients for Geologic Trial 2a. .......................... 69 Table