9508257 Brown The goal of this study is to carefully integrate a variety of innovative geochemical techniques that build upon detailed descriptions of geological, alteration and radiogenic work done by the P.I.s or researchers from the key Centre in Perth. It is planned to quantify the hydrothermal fluid components of the fossil hydrothermal systems with detailed fluid inclusion, FTIR and laser-Raman spectroscopy, gas- and ion-chromatography, and laser stable isotope analyses. In addition, new innovative noble gas and the PIXE probe analyses on carefully selected individual as well as groups of fluid inclusions will be used to constrain, for the first time, metals (such as Au, Cu, As, Sb), argon and groups of fluid inclusions. This data will then be used to quantify possible chemical processes such as fluid immiscibility and/or fluid mixing at the different crustal levels. This study will have profound influence on the worldwide search for gold deposits that are hosted in very low- and high-grade metamorphic terrains, possibly still concealed beneath the surface.