The Interaction of Organic Matter and Fluids during the Genesis of Some Precious Metal and Volcanogenic Massive Sulfide Deposits
Richard M. Ketiler, 1997. "The Interaction of Organic Matter and Fluids during the Genesis of Some Precious Metal and Volcanogenic Massive Sulfide Deposits", Ore Genesis and Exploration: The Roles of Organic Matter
Download citation file:
Despite the near-ubiquity of reduced carbon in many different types of epigenetic and exhalative ore deposits, it has been difficult to relate the reduced carbon to ore transport and deposition in many of these systems. This is particularly true with most precious metal deposits. Whereas many base metal deposits (e.g., Mississippi Valley-type or sedimentary exhalative, sedex, deposits) are restricted to sedimentary rocks and appear to be related to the evolution of sedimentary basins, many types of precious metal deposits are hosted in both organic carbon-rich sedimentary rocks and in volcanic rocks that contain little organic matter. If there are sufficient similarities in the mineralization and alteration observed in the igneous and sedimentary rocks, then any model of ore deposition that appeals to organic matter seems unnecessarily ad hoc. Efforts to produce simple and robust models of ore deposition combined with the refractory nature of the organic matter in many systems have led various workers to underrate the significance of organic matter in many epigenetic precious metal deposits. This situation is changing: improved analytical techniques can be used to document the presence of organic species in hydrothermal systems, the importance of bulk-minable ore deposits requires that wall-rock chemistry receive greater consideration, and continued interest in the role of organic matter in ore mineralization has prompted closer scrutiny of those systems that contain organic matter. This review will use a number of epigenetic precious metal deposits as examples and consider the significance of organic matter to ore deposition for each (see also Leventhal and Giordano, 2000; Giże, 2000; and Pratt and Warner, 2000). The review will also include a short discussion of volcanogenic massive sulfide mineralization and the significance of organic matter to these exhalative systems (see also Simoneit, 2000).