Gaspé Cu (824 Mt @ 0,27% Cu and 0,015% Mo) is an advanced project of Osisko Metals, it is a Devonian porphyry-skarn Cu-Mo deposits located in the Gaspé Peninsula of Québec. The Gaspé Cu deposit is formed around two main felsic porphyry stocks (Copper and Porphyry Mountains) intruding a thick sequence of mudstones, siltstones, and limestones. Porphyry-style mineralization is centered around the two porphyry stocks, in addition, Cu skarn mineralizations are well developed along favorable limestone layers, up to 2 km from the porphyry plugs, as well as Curich carbonate replacement bodies. Both porphyry-style and skarn mineralizations are associated with a large alteration system affecting the sediments and characterized by a proximal garnet diospide, an intermediate tremolite-calcite, and a distal phlogopite zone.
The U. Laval (Québec City)-UQAM (Montréal) joint project has two main objectives. The first is to characterize the fluid evolution along the porphyry and skarn mineralizations with a focus on the precipitation mechanisms of critical and precious metals (In, Te, Bi, Ag and Mo). The second one is to characterize (petrography, SWIR, chemistry) the alteration haloes with a focus on the distal footprints in the sediments.
The selected students will complete an existing team of two PhD and one MSc working on Gaspé Cu and the Gaspé Peninsula, mostly focusing on the magmatic system. In addition, they will join in both universities a large active team of international graduate students working on different thematics related to economic geology, metamorphism, and geodynamics. Both PhD projects are hosted in francophone universities (U. Laval and UQAM), French knowledge is considered as an asset but is not mandatory.
Candidates should prepare a complete candidacy package which includes: (1) a long-form CV that includes publications and research achievements, (2) academic transcripts, (3) letter of motivation, (4) names and contact details of three references. The full application package should be sent electronically as a single PDF document to bertrand.rottier [at] ggl.ulaval.ca (bertrand[dot]rottier[at]ggl[dot]ulaval[dot]ca). Applications will be accepted until the 1st of December.
PhD 1: Reconstruction of P-T-X fluid evolution in the Gaspé Cu-Mo porphyry-skarn deposit – a focus on the critical metals.
Location: Université Laval (Québec City)
Starting date: May 2026
Duration: 3.5 years
Salary: 27,000 CAD / year
Supervisors: Bertrand Rottier (U. Laval), Georges Beaudoin (U. Laval), Stéphane De Souza (UQAM)
Fluid evolution during porphyry Cu formation is well-understood, however, the transition between porphyry- and skarn-type mineralizations are still not well defined. In addition, the behavior of selected critical and precious metals (In, Bi, Te, Ag, and Mo) during the formation of both deposit types remains poorly understood, hampering our comprehension of the factors controlling their enrichments in both deposit types.
The main objectives of this project is to track the fluid evolution along the porphyry- and skarn-type mineralizations with a focus on several critical and precious metals (In, Bi, Te, Ag, and Mo) in order (i) to define their distribution at the scale of the deposit and (ii) to document the different physicochemical factors leading to their precipitation and local enrichment.
The selected candidate will perform a detail sampling, using available drill-core, of the porphyry-type mineralization at Cu Mountains and of the skarn mineralization along the C and E horizons (see map). The samples will be characterized by classical petrography, micro XRF maps and SEM-CL images. Fluid inclusions (microthermometry + LA-ICP-MS) analyses will be performed on gangue (quartz, garnet, pyroxene, anhydrite) and ore minerals (sphalerite, pyrite)
using classical and near infrared transmitted light microscopy. EPMA and LA-ICP-MS analyses will be performed on the different ore minerals (chalcopyrite, pyrite, bornite, sphalerite…) to determine their concentration in critical and precious metals.
Previous experience with ore petrography, mineral chemistries, and/or fluid inclusion study will be considered as an asset.
PhD 2: Characterization of the alteration haloes of the Gaspé Cu porphyryskarn deposit – a focus on the distal footprint
Location: UQAM (Montréal)
Starting date: May 2026
Duration: 3.5 years
Salary: 27,000 CAD / year
Supervisors: Stéphane De Souz (UQAM), Benoît Saumur (UQAM), Bertrand Rottier (U. Laval)
Alteration systems associated to porphyry-Cu deposits are well understood, however, much of our knowledge is from deposits hosted in magmatic rocks and the mineralogy, the zonation and the extent of the alteration haloes of porphyry-Cu deposits hosted in sediments are still not well defined. Gaspé Cu is a perfect case study to fill this gap, as a well-zoned alteration system has already been described and can roughly be summarized as a proximal garnet-diospide, an intermediate tremolite-calcite, and a distal phlogopite zone that extend more than 2 km from the porphyry center.
The selected candidate will characterize the mineralogy, the SWIR signature and the chemistry of the alteration haloes around the Copper Mountain porphyry-type mineralization and the skarn mineralization along a N-S profile. The main objective will be (i) to characterize the alteration zones and to model these in 3 dimensions, (ii) to determine their petrography and mineralogical variability in the different sedimentary rocks and (iii) to define their extents to
develop new exploration vectors.
To reach this objective, SWIR measurements will be systematically performed directly in the field on selected drill-cores. Representative samples will be selected for detailed petrographic characterization through classical microscopy and micro-XRF mapping. The chemical evolution of selected minerals (i.e., phlogopite) as function of the distance with the mineralization will be determined using EPMA and LA-ICP-MS analyses.
Previous experience with SWIR analyses and mineral chemistry will be considered as an asset.