This project is to extend studies of S isotope systematics to other continental hydrothermal systems, making use of new drillcores and fluid samples from active geothermal systems as well as fossil epithermal gold deposits. The PI will examine the general systematics of sulfur isotopic zoning of sulfide minerals in response to boiling and other forms of fluid immiscibility in ore-forming environments. The generality of the proposed parallel effects on precious metals deposition will also be tested at several localaties. In addition to the Valles Caldera, the Geysers and Coso geothermal fields in California offer two active settings where boiling and precious metals deposition occur. Additionally, the McLaughlin and Cactus Queen gold deposits in California offer two fossil epithermal systems where similar systematics may have existed during ore genesis.
