Trace elements and ore formation in the Troodos and Parys Mountain VMS systems: A link to modern seafloor massive sulphide deposits?

摘要

Seafloor massive sulphide (SMS) deposits are typically rich in base metals, such as Fe, Cu, Zn and Pb, and there formation is genetically linked to active hydrothermal vent systems (Hannington et al. 2010). These deposits are thought to be analogous to ancient volcanogenic massive sulphide (VMS) deposits. This study aims to identify if ancient VMS deposits can be used as analogues for SMS deposits. For this study, two genetically distinct, previously mined VMS systems were chosen. The Troodos VMS deposits are hosted within the 90 Ma Troodos ophiolite, which formed in a sediment-starved, supra-subduction environment (Robertson 2002). The 436 Ma Parys Mountain mineralisation formed within a back-arc during subduction of the lapetus ocean as part of a sediment-covered hydrothermal system (MacLean et al. 2001). These ancient systems will be compared to data from modern SMS systems, including the deposits in the Escanaba Trough on the Gorda Ridge, and the TAG mound on the Mid-Atlantic Ridge.