Timing of Gold Mineralization at Red Lake, Northwestern Ontario, Canada:New Constraints from U-Pb Geochronology at the Goldcorp High-Grade Zone,Red Lake Mine, and the Madsen Mine

Abstract

The Goldcorp High-Grade zone at the Red Lake mine has reserves (proven and probable) established at 1.775 million tons (Mt) at an average grade of 80.6 g/t Au. New U-Pb geochronologic data combined with detailed mapping and crosscutting relationships provide timing constraints and new insights into the formation of the exceptionally rich Goldcorp High-Grade zone. The results show that the main stage of the high-grade mineralization in the High-Grade zone formed before 2712 Ma and that a second stage of gold mineralization, much smaller in terms of total gold content but spectacular in terms of grade, formed after 2702 Ma. This second stage is attributed to gold remobilization caused by the enhanced thermal gradient and deformation associated with the emplacement of the Cat Island pluton (2699 Ma), approximately 7 km east of the deposit, or by the ca. 2.63 to 2.66 Ga postorogenic regional thermal event indicated by hornblende, muscovite, and biotite Ar-Ar cooling ages from the Uchi subprovince. It is proposed that the main stage of high-grade mineralization formed between ca. 2723 to 2712 Ma, possibly synchronous with emplacement of the Dome and McKenzie Island stocks, the Abino granodiorite, and Hammell Lake batholith, as well as with penetrative D 2 main-stage regional deformation.

Direction of material creep during the deformation phase in shear zones, role in mining prospecting: A case of the Nassara-Torkera gold deposits in the Gaoua region, Burkina Faso, West Africa

“…However, this spatial link between mineralization and the various dykes indicates that the mineralizing fluids follow the same structures with the dikes. Some authors (Muller et al, 1992;Taylor et al, 1994;Dubé et al, 2004) believe that there is no direct genetic link between lamprophyres and gold in the various deposits, but rather a spatial link. Some studies have demonstrated that the altered dikes are rich in gold due to mineralizing hydrothermal fluids (Kerrich and Wyman, 1994;Wyman et al, 1995).…”

Abstracts

“…Geostatistical analysis of the normal and higher grade domains was undertaken, followed by Quantitive Kriging Neighbourhood Analysis Variogram analysis to identify the optimal estimation parameters to apply in terms of the search ellipse sizes, and minimum and maximum number of samples, used for accurate block model grade interpolation. The Red Lake greenstone belt in the Superior Province, Canada, hosts several past, present and prospective Au deposits, including the currently producing Red Lake Gold Mines (RLGM; 40 Mt at 20 g/t), and mineralised occurrences aligned E-W along the Red Lake Mine trend (Dube ´et al, 2004) towards the recently reactivated Cochenour-Willans mine. Volcano-sedimentary assemblages which have been metamorphosed to upper greenschist-amphibolite facies (Thompson, 2003) composing the greenstone belt includes the Balmer assemblage consisting of submarine tholeiitic and less frequent komatiitic basalt with minor rhyolite and BIF packages (Sanborn-Barrie et al, 2001).…”

“…The Balmer assemblage hosts Au-mineralisation. Three deformation events are recorded: D 1 , an initial E-W shortening, D 2 , an N-S shortening and D 3 , late extension and brittle deformation (Dube ´et al, 2004;Sanborn-Barrie et al, 2001).…”

“…Fluid inclusion analysis and Re-Os dating of molybdenite in main-and late-mineralisation stage veins are now underway to determine the evolving characteristics of Mo-transporting hydrothermal fluids and the absolute timing of Mo mineralisation at El Teniente. The Red Lake Gold Mines (40 Mt at 20 g/t), an Archean lode-gold deposit in the Superior Province, Canada, formed as a result of multiple superposed hydrothermal and metamorphic (Dube ´et al, 2004). Pervasive early hydrothermal alteration of biotite¡carbonate was widespread but barren with subsequent regional metamorphism producing a greenschist-amphibole facies (Thompson, 2003).…”

Mapeamento hiperespectral de associações minerais relacionadas ao depósito de ouro de Pedra Branca, Maciço de Troia, Ceará

“…Os corpos magmáticos compreendem batólitos, stocks, sills e diques, em sua maioria félsicos a intermediários, embora também seja comum a ocorrência de lamprófiros . Uma minoria significativa dos depósitos de ouro orogênico é hospedada, ou aloja-se nas adjacências de granitoides e relações de contato sugerem que a deformação regional segue em andamento durante o magmatismo e atividade hidrotermal, uma vez que veios mineralizados truncam corpos ígneos deformados e não deformados numa mesma província aurífera (Dubé et al 2004;. Intrusões prévias às mineralizações proporcionam um contraste de competência com as rochas encaixantes e, assim, alguns depósitos importantes estão alojados em estruturas sobrepostas a complexos ígneos, sendo as margens cisalhadas de stocks e a margem exterior de batólitos em arcos magmáticos as zonas de maior favorabilidade ao desenvolvimento de veios mineralizados (Haeberlin et al 2004;.…”