The Dorset showings: mesothermal vein-type gold occurrences associated with post-Ordovician deformation along the Baie Verte-Brompton Line, Baie Verte Peninsula, Newfoundland

Abstract

The Dorset gold showings are mesothermal vein-type gold occurrences located close to the Baie Verte-Brompton Line. Mineralization occurs in fault-fill veins hosted by Ordovician and Silurian volcanic and volcaniclastic rocks of the Dunnage zone. Auriferous quartz veins are located in the central part of high strain zones and are spatially associated with fine grained mafic dykes. Development of high strain zones is facilitated by strength anisotropy induced by the mafic dykes. Deformation-induced secondary permeability in high strain zones concentrates the fluid circulation which is responsible for the gold mineralization. Structural elements suggests that development of the high strain zones and the gold mineralization are related to a major compressive event. The timing of the mineralizing event is syn- to post-Silurian and could be related to the Silurian reactivation of the Baie Verte-Brompton Line. Late movements contributed to deform the gold-bearing quartz veins.