https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:3418 Sat 24 Mar 2018 07:21:38 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:3421 21.0 eq. wt.%, respectively). Heating experiments indicate minimum temperatures of trapping of 350 641°C for Type-I inclusions, 207 660°C for Type-II inclusions, and 143 <637°C for Type-III inclusions. Oxygen isotope compositions of quartz–actinolite and albite–actinolite pairs indicate a temperature of gold-associated alteration of ~350°C, consistent with arsenopyrite thermometry, which indicates gold mineralization at <480°C. The early CO₂-rich fluid inclusions have densities that range from 0.6 to 1.05 g/cm3 which, at 350°C, correspond to 1–2 kbar pressure, consistent with geological relations indicating that the McPhees deposit formed at <7 km. Type-I inclusions are interpreted to contain early vein-related fluids that carried gold, but this assemblage (nearly pure CO₂ and subordinate, coexisting H₂O-rich fluid inclusions) is unusual for orogenic gold deposits. It is most likely a result of fluid mixing that may have played a role in gold deposition in veins; however, host-rock lithology seems to have been a first-order control in localizing the gold.]]> Sat 24 Mar 2018 07:21:37 AEDT ]]>