Structural controls on multistage gold mineralisation within the Baie Verte Peninsula of Newfoundland, Canada

The Baie Verte Peninsula (BVP) is one of the richest auriferous regions within the Newfoundland Appalachians hosting more than 100 economic and sub-economic gold occurrences. The geological setting of the BVP resulted from the accretion of several micro-terranes of Iapetus origin to the Laurentian margin during the Ordovician Taconic Orogeny. The Baie Verte Line (BVL), a major crustal fault, represents the suture between the Laurentian margin and the accreted island arcs. Subsequent progressive deformation (D2) developed under a sinistral transpressional setting during the Salinic and Acadian orogenic events. Later deformational phases (D3-D4) resulted in response to complex dextral transcurrent motions localised along the BVL during the Neo-Acadian Orogeny.
The studied gold occurrences, Stog’er Tight, Argyle, Romeo & Juliet, Deer Cove, and Pine Cove lie along splays of the BVL. New structural, mineralogical, and geochronological data has been collected through geological mapping, optical and SEM/CL investigations of mineralized samples, and in-situ LA-ICP-MS U-Th-Pb geochronology of monazite, xenotime, and titanite. Structural data analysis showed that at least three deformational events (D2-D4) influenced the formation and the present geometry of the gold deposits. Mineralogical and geochronological data revealed complex paragenetic sequences in each deposit and at least two periods of gold precipitation.
The age of the first gold mineralising moment is constrained between ~420 to 410 Ma. The mineralised veins formed during the D2 progressive deformation, under brittle-ductile conditions, broadly synchronous with the development of E-W striking and south directed thrusts, splays of BVL.
The maximum age of the second gold mineralising event is ~396 Ma, whereas the best estimate age is ~380 Ma. The gold bearing veins formed during the D3-D4 deformational events. At this time the entire BVP was under extension-related exhumation processes. Currently, it is unclear whether the later mineralising fluids either augmented the existing gold endowment or remobilized the pre-existing gold.