................................................................................................................................................ iii Acknowledgements .............................................................................................................................. vii Dedication ........................................................................................................................................... viii List of Figures ..................................................................................................................................... xiv List of Tables ....................................................................................................................................... xvi Author’s Note ......................................................................................................................................... 1 Chapter 1: Introduction ........................................................................................................................... 4 1.1 Chemistry of the Platinum Group Elements (PGE) ...................................................................... 4 1.2 Importance of PGE research ......................................................................................................... 6 1.2.1 Core/Mantle segregation ....................................................................................................... 6 1.2.2 PGE ore deposits ................................................................................................................... 7 1.2.2.1 Role of volatiles in the genesis of PGE deposits ............................................................ 7 1.2.2.1.1 Non-conventional .................................................................................................... 7 1.2.2.1.2 PGE occurrences in association with layered mafic intrusions ............................... 7 1.2.2.2 R-Factor Model .............................................................................................................. 8 1.2.2.3 Magmatic-Hydrothermal Model ..................................................................................... 9 1.3 History of experimental work on PGE solubility in silicate melts and fluids ............................ 10 1.3.1 Solubility Experiments ........................................................................................................ 11 1.3.1.1 Stirred Crucible Method (Mechanically Assisted Equilibration) ................................. 11 1.3.1.2 Wire-loop Method ........................................................................................................ 12 1.3.2 Micronuggets ....................................................................................................................... 13 1.3.3 Experimental studies on the solubility of PGEs in a volatile phase .................................... 15 1.4 The role of volatiles in evolving magmatic systems .................................................................. 17 1.4.1 Water ................................................................................................................................... 18 1.4.1.1 Solubility and speciation .............................................................................................. 18 1.4.1.2 Physical effects ............................................................................................................. 19 1.4.1.2.1 Melting temperature .............................................................................................. 19