Timing and depth of mineralisation in the Irish Zn-Pb orefield.

The occurrence of vent fauna and isotopic evidence for surface fluid interactions support a near-seafloor origin for the economic mineral deposits of the Irish orefield. Classically epigenetic mineralisation represents a minor component of the ore systems and is believed to have formed at depth, in part synchronously with overlying, near-seafloor sulphides that precipitated in partially lithified sediment. Constraints from fluid PVT modelling suggest that some of the later paragenetic phases related to such activity formed at depths of at least 165 m beneath the seafloor. True exhalative components are restricted in occurrence and appear to be best developed in the SW of the orefield. It is possible that mineralisation was diachronous as well as episodic.
The occurrence of vent fauna and isotopic evidence for surface fluid interactions support a near-seafloor origin for the economic mineral deposits of the Irish orefield. Classically epigenetic mineralisation represents a minor component of the ore systems and is believed to have formed at depth, in part synchronously with overlying, near-seafloor sulphides that precipitated in partially lithified sediment. Constraints from fluid PVT modelling suggest that some of the later paragenetic phases related to such activity formed at depths of at least 165 m beneath the seafloor. True exhalative components are restricted in occurrence and appear to be best developed in the SW of the orefield. It is possible that mineralisation was diachronous as well as episodic.