Abstract

Associations between calc-alkaline lamprophyres and mesothermal gold deposits (Archean to Tertiary) in which the lamprophyres are coeval (as well as cospatial) with mineralization are increasingly recognized worldwide. Our suggested hypothesis regards lamprophyres as transporting agents for Au from Au-rich sources in the deep mantle, which then undergo extensive crustal interactions, generating felsic magmas or releasing their Au into metamorphic-hydrothermal systems. Such a model not only may reconcile the conflict between the extant magmatic and metamorphic models for mesothermal deposits but also may resolve the inconclusive relations between gold deposits and felsic (porphyry-granitoid) intrusions, because lamprophyres may act as parents to both. The gold-lamprophyre association implies that exceptionally deep-seated magmatism repeatedly accompanied gold mineralization in postcollisional orogenic, island-arc, oblique subduction, or graben environments. This has important implications for the late-stage evolution of mineralized Archean greenstone belts in particular, and for gold deposit genesis in general.

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