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Fingerprinting Source Fluids of Iron Oxide-Copper-Gold and Iron Oxide- Apatite Deposits Using Traditional and Non-Traditional Stable Isotope Geochemistry

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Fingerprinting Source Fluids of Iron Oxide-Copper-Gold and Iron Oxide- Apatite Deposits Using Traditional and Non-Traditional Stable Isotope Geochemistry Fingerprinting Source Fluids of Iron Oxide-Copper-Gold and Iron Oxide- Apatite Deposits Using Traditional and Non-Traditional Stable Isotope Geochemistry by Tristan Morgan Childress A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Earth and Environmental Sciences) in the University of Michigan 2019 Doctoral Committee: Professor Adam Charles Simon, Chair Research Professor Jeffery Alt Associate Professor Rebecca D. Hardin Professor Emeritus Stephen Kesler Professor Kyger Lohmann If you awaken from this illusion and you understand that black implies white, self implies other, life implies death (or shall I say, death implies life), you can feel yourself – not as a stranger in the world, not as something here on probation, not as something that has arrived here by fluke - but you can begin to feel your own existence as absolutely fundamental. — Alan Watts, “The Dream of Life” Tristan Morgan Childress [email protected] ORCID iD: 0000-0002-2827-9379 © Tristan Morgan Childress 2019 DEDICATION This work is dedicated to my family who has supported me throughout my academic career and dealt with the long distance with love and grace. To my mother, Sharon, who has encouraged me to reach higher and think outside the boundaries of convention. To my father, Tony, who taught me to love and respect the outdoors. To my sister, Tiffany, a true role model of someone who can not only raise a wonderful family, but also build a successful career simultaneously. To her husband and sons, Mark, Brandt, and Fischer, who lift my spirits whenever I’m home. Finally, to my late grandparents, Colene and Eugene Morgan and Arnette Childress, who taught me the virtues of hard honest work, and who I miss every day. ii ACKNOWLEDGEMENTS First off, I must thank my dissertation committee, Drs. Kacey Lohmann, Steve Kesler, Jeffrey Alt, and Rebecca Hardin, for all of their time, comments, encouragement, and discussion over the past few years, which made my thesis all the stronger and more enjoyable to read. I must sincerely thank my advisor, Dr. Adam Simon, who took a chance bringing me to the University of Michigan and encouraged me through all of my hard work that has helped me become the geologist I am today. Without the incredible assistance of Drs. Ilya Bindeman and Jim Palandri at the University of Oregon and Dr. Craig Lundstrom and Zhenhao Zhou at the University of Illinois Urbana-Champaign I would have never managed such quality isotopic data in such efficient time. Ilya and Jim are an oxygen isotope powerhouse (seriously, I’m jealous of their setup) and ran so many samples for my research I have lost count. I must especially thank Craig, who managed to not only assist me in my Fe isotope analyses, teaching me how to run the instrument, but also managed to deal with all the technical headaches I caused, and for that I am very grateful. These gentleman taught me invaluable lessons regarding isotopes as well as mass spectrometry. This research has taken me to Chile several times over the years, a beautiful country with lovely people, bursting with culture. While there I met many great geologists, namely my coauthors Drs. Martin Reich and Fernando Barra. Their knowledge of Chilean geology and the iii iron oxide deposits is incredible, and spending even a few days with them was worth more than any short course. During that time I met many of their students who became great friends during our time in the Atacama, and who I am certain will go on to become great geologists like their advisors. While working in the office here at the University of Michigan, I met many great professors and researchers with whom I could chat about science or life. Dr. Aaron Wolf hosted the MRM group that encouraged us to “think deeper” and more critically about what is happening in the earth’s mantle and core (as well as what’s going on in outer space), and how that relates to my own research in the Earth’s crust. Dr. Jamie Gleeson has been a great next door friend who was always up for a beer and chat and is always in good spirits. Drs. Nathan Niemi and Ben van der Pluijm provided a much needed insight into tectonics and mapping, and great laughs along the way. The camaraderie within our department has always been impressive. Beginning in the first year office I became great friends with now Dr. Brian Konecke who I also lived with during my first year (and probably had too many beers with). I could always destress with my cohort at the bar after a hard day’s work. I will always remember the long talks Brian, Laura Motta, and I had about rocks, spiritualism, and aliens (we are the “crazy” ones). A big thanks goes out to all of the students here now and in the past that have helped me both academically and mentally over the years. The Simon lab group has been a cornerstone in my academic career, and always will be. Dr. Laura Bilenker was an amazing mentor and very close friend who taught me everything I needed to know about iron isotopes when I first arrived here, and helped me through some of the harder mental challenges of being a PhD student through the years, for which I will always be iv grateful. Drs. Liz Tannis, Jaayke Knipping, Adrian Fiege, and Tom Hudgins were great mentors and always great for a laugh. Nikita la Cruz, official member of the “El Simon Dream Team” along with Brian and I, has been an incredible officemate, roommate, and friend. Thank you for putting up with Ravi “singing” in the night and playing hide and seek in your bedroom. Honorary lab cousin and cat-god parent Xiaofei Pu has taken great care of my cats Ravi and Norah while I was away at Red Dog Mine during the summers, and we are eternally grateful for you. Daniel Korfeh and Gephen Sadove were the best office mates I could have asked for, and Daniel in particular always pushed me to ask “Why!? Why is there so much titanium in magnetite??” I have no doubt that our newest lab members, Maria AR Mustafa and Jackie Wrage, will live up to the excellence in this lab group and excel in their studies. I would never have made it this far in my career without the initial guidance and friendship of Dr. Kerry McCarney-Castle, who was head of the research project I worked on at the South Carolina Geological Survey prior to beginning at the University of Michigan. She can lay claim to my original geological role model. And a special thanks goes out to all of the great people I worked with during the summers at Red Dog Mine, who helped me take a step back from my research to understand the bigger picture of how geology fits into society on a grander scale. The past several years of research has introduced me to so many wonderful and intelligent people, all of whom I am not able to mention here, but to all of whom I am sincerely grateful and appreciative. v TABLE OF CONTENTS DEDICATION……………………………………………………………………………...……ii ACKNOWLEDGEMENTS………………………………………………………...…………..iii LIST OF TABLES………………………………………………………………...……………vii LIST OF FIGURES……………………………………………….……………………..………x ABSTRACT…………………………………………………………..……………...…………xii CHAPTER I. INTRODUCTION……………………………………………………………….1 1.1. IRON OXIDE DEPOSITS……………………………………………..……………...……..1 1.2. IRON OXIDE CHEMISTRY…………………………………………………………...……3 1.3. TESTING IOA AND IOCG MODELS………………………………………………………5 1.4. APPLICATION OF FE, O, AND H ISOTOPIC SYSTEMS AND TRACE ELEMENT ANALYSIS TO IOA AND IOCG DEPOSITS……………………………………………….6 1.5. REFERENCES……………………………………………………………………………….9 CHAPTER II. IRON AND OXYGEN ISOTOPE SIGNATURES OF THE PEA RIDGE AND PILOT KNOB MAGNETITE-APATITE DEPOSITS, SOUTHEAST MISSOURI, USA……………………………………………………………………………….……………..14 2.1. INTRODUCTION………………………………………………………………….……….15 2.2. GEOLOGIC BACKGROUND……………………………………………………..……….18 2.3. SAMPLE SELECTION AND MAGNETITE CHARACTERIZATION…………….……..22 2.4. STABLE ISOTOPE ANALYTICAL METHODS………………………………………….24 2.5. RESULTS…………………………………………………………………………...………26 2.6. DISCUSSION……………………………………………………………………………….27 2.7. FINAL REMARKS……………………………………………………...………………….37 2.8. ACKNOWLEDGEMENTS…………………………………………………………………37 2.9. REFERENCES…………………………………………………………………………...…38 CHAPTER III. FORMATION OF THE MANTOVERDE IRON OXIDE - COPPER - GOLD DEPOSIT, CHILE: INSIGHTS FROM FE AND O STABLE ISOTOPES AND COMPARISON TO IRON OXIDE - APATITE DEPOSITS……………………...………..48 3.1. INTRODUCTION…………………………………………………………………………..50 3.2. GEOLOGIC BACKGROUND AND PREVIOUS STUDIES AT MANTOVERDE….…...53 3.3. METHODS.............................................................................................................................59 3.4. RESULTS…………………………………………………………………………...………64 3.5. DISCUSSION……………………………………………………………………………….65 vi 3.6. CONCLUSIONS…………………………………………………………..………………..88 3.7. ACKNOWLEDGEMENTS……………….………………………………..……………….89 3.8. REFERENCES…………………………………………………………………..………….89 CHAPTER IV. TRIPLE OXYGEN, HYDROGEN, AND IRON STABLE ISOTOPES SIGNATURES INDICATE A SILICATE MAGMA SOURCE AND MAGMATIC- HYDROTHERMAL GENESIS FOR MAGNETITE ORE BODIES AT EL LACO, CHILE.........................................................................................................................................102 4.1. INTRODUCTION…………………………………………………………………………103 4.2. GEOLOGIC BACKGROUND…………………………………………………….………106 4.3. METHODS………………………………………………………………………..……….111 4.4. RESULTS………………………………………………………………………………….116 4.5. DISCUSSION……………………………………………………………………...………118 4.6. CONCLUSIONS…………………………………………………………………………..133 4.7 ACKNOWLEDGEMENTS………………………………………………………….……..134 4.8. REFERENCES………………………………………………..……………………….…..135 CHAPTER V. CONCLUSIONS………………………………………….……………….….145
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