Integrated 3D Geological Modeling to Gain Insight in the Effects of Hydrothermal Alteration on Post-Ore Deformation Style and Strain Localization in the Flin Flon Volcanogenic Massive Sulfide Ore System

Abstract

3D geological modeling of lithogeochemical and geological data provides insight into the role of the sulfide ore horizon and associated footwall hydrothermal alteration in localizing shear strain in the Flin Flon volcanogenic massive sulfide deposits, Canada, as deformation evolved from brittle-ductile to ductile regimes during collisional stages of the 1.9-1.8 Ga Trans-Hudson orogeny. 3D spatial characterization of hydrothermal alteration based on the Ishikawa index (AI) and normative corundum percentages outline sericite + chlorite-rich high strain zones, consisting of Al-enriched and Na-depleted felsic and mafic volcanic rocks in the footwall of the sulfide ore horizon. The hydrothermal vent complex, from which these sheared alteration zones originated, was stacked together with the ore horizon by W-vergent thrust faults during an early collisional deformation regime, imbricating molasse-type clastic sediments with the ore-hosting volcanic and volcaniclastic rocks of the Flin Flon arc assemblage. Chlorite-rich planar zones marked by high values of the Carbonate-chlorite-pyrite index (CCPI) are laterally more extensive and outline a later system of ductile shear zones, in which phyllosilicates, quartz and chalcopyrite in stringer zones localized shear strain and enhanced transposition of the hydrothermal vent stockwork. The contrasting deformation styles of these two thrusting events and their localization within the ore horizon and hydrothermal vent stockwork have important implications for vectoring towards undiscovered ore in this mature mining camp that are possibly also relevant to other strongly deformed VMS ore systems.

In situ Lu–Hf geochronology of calcite

“…Zn-Cu mineralisation is interpreted as having formed contemporaneously with deposition of the 1888.9 ± 1.6 Ma Millrock Member during the Trans-Hudson Orogeny (Koo and Mossman, 1975;Rayner, 2010;Gibson et al, 2012). The Flin Flon Zn-Cu orebody is recognised as having undergone six distinct deformation events that have affected the shape of the deposit (Lafrance et al, 2016;Schetselaar et al, 2017). "D 1 " and D 2 were associated with the intra-oceanic accretion of the Flin Flon Arc to other volcanic terrains before ca.…”

In-situ Lu – Hf geochronology of calcite

“…Zn-Cu mineralisation is interpreted to have formed contemporaneously with deposition of the 1888.9 ± 1.6 Ma Millrock member during the Trans-Hudson Orogeny (Gibson et al, 2012;Koo and Mossman, 1975;Rayner, 2010). The Flin Flon Zn-Cu orebody is recognised to have undergone six distinct deformation events that have affected the shape of the deposit (Lafrance et al, 2016;Schetselaar et al, 2017). 'D1' and 'D2' were associated with the intra-oceanic accretion of the Flin Flon Arc to other volcanic terrains before ca.…”

3D Geological Model of the Touro Cu Deposit, A World-Class Mafic-Siliciclastic VMS Deposit in the NW of the Iberian Peninsula

“…The use of 3D geological models to facilitate the understanding of surface and subsurface geology is well-established by many authors (i.e., [15][16][17][49][50][51][52][53][54]).…”

“…The methodology used in the Touro 3D geological modeling was implemented in a system consisting of a GIS, a spatial database and a 3D modeling software [53][54][55][56]. It involves several different steps for processing data, depending on the ore type (Figure 3A-C Different drilling surveys performed from 1960 to that most recently carried out by Atalaya Mining were used to reconstruct the 3D geometry of the deposits.…”