Deciphering the Evolution of Ore Fluids at The Batu Hijau Copper-~Gold Porphyry Deposit, Sumbawa, Indonesia

................................................................................................................................................... iii ACKNOWLEDGMENTS ............................................................................................................................. v LIST OF TABLES ..................................................................................................................................... viii LIST OF FIGURES ....................................................................................................................................... ix CHAPTER 1: INTRODUCTION ............................................................................................................... 1 CHAPTER 2: GEOLOGIC BACKGROUND ........................................................................................... 3 CHAPTER 3: METHODS ........................................................................................................................... 7 Sample Selection ................................................................................................................................................. 7 Macroscopic & Microscopic Petrography ................................................................................................. 8 Fluid Inclusion Petrography .......................................................................................................................... 9 Microthermometry .......................................................................................................................................... 12 Synchrotron X‐Ray Flourescence (SXRF) ............................................................................................... 12 Laser Ablation–Inductively Coupled Plasma–Mass Spectrometry (LA‐ICP‐MS) ................... 14 CHAPTER 4: PETROGRAPHIC STUDY ............................................................................................ 15 Fluid Inclusion Origins ................................................................................................................................... 15 Fluid Inclusion Types ...................................................................................................................................... 16 Fluid Inclusions Abundances ....................................................................................................................... 17 CHAPTER 5: MICROTHERMOMETRY ............................................................................................. 20 Microthermometric Data ............................................................................................................................... 20 Microthermometric Discussion .................................................................................................................. 22 Constant Density Isochors ............................................................................................................................ 22 Inclusions Depths & Pressures ................................................................................................................... 24 Trapping Temperatures ................................................................................................................................ 24 CHAPTER 6 : SYNCHROTRON X‐RAY FLOURESCENCE .......................................................... 27 SXRF Data ............................................................................................................................................................. 27 SXRF Discussion ................................................................................................................................................ 30 CHAPTER 7: LASER ABLATION‐INDUCTIVELY COUPLED PLASMA‐MASS SPECTROMETRY ..................................................................................................................................... 34 LA‐ICP‐MS Data ................................................................................................................................................. 34 X‐Y Plots ............................................................................................................................................................... 36 X/Na Plots ............................................................................................................................................................ 38 Discussion of X‐Y and X/Na Plots .............................................................................................................. 46 Spatial distribution of Cu Concentrations in Fluid Inclusions ....................................................... 48 Copper concentrations and their relation to known Cu grades .................................................... 51 Absense of Au in LA‐ICP‐MS results ......................................................................................................... 53 CHAPTER 8: MODEL FOR DEPOSIT FORMATION .................................................................... 53 Fluid 1: VB60 Inclusions ................................................................................................................................ 56 Fluid 2: VB35, VB20H, and VB85s Inclusions ....................................................................................... 57 CHAPTER 9: CONCLUSIONS ............................................................................................................... 62 TABLES ........................................................................................................................................................ 63