The association of gold—mercury mineralization and hydrocarbons in the coast ranges of northern California

The association of oils and bitumen with ore deposits has been long recognized and widely recorded (e.g. Parnell, 1988). In the Coast Ranges of northern California hydrocarbons occur in late Tertiary and Quaternary gold—mercury and mercury-only deposits as well as active geothermal systems that are considered modern day analogues of the epithermal systems (Whitney, 1865; Bradley, 1916; White, 1967; Pearcy and Burruss, 1993; Peabody, 1993). The superb preservation of textures and geological relationships in the hydrothermal systems allows the role of hydrocarbon with respect to gold and mercury mineralization to be empirically assessed.