ABSTRACT
The Western Cordillera of Ecuador hosts three Au-rich Cu-Zn VHMS deposits within an Early Tertiary island arc sequence, now accreted to the continent. The deposits are characterized by pyrite-chalcopyrite mineral parageneses including bornite, covellite, digenite, tennantite, and are affected by a quartz-sericite alteration. Lead isotope compositions are homogeneous within each deposit but differ significantly among the three orebodies, even if two of them are only 1.5 km apart. Lead isotope compositions of the orebodies overlap those of the volcanic host rocks and are consistent with lead derived from mixing of pelagic sediments, mantle and oceanic crust. Geological setting mineralogy, and gold grades of the VHMS deposits of the Western Cordillera of Ecuador bear some similarities to those of recent and present-day massive sulfides of the W-Pacific.
