ÉLÉONORE

GEOLOGY

Regional Geology | Local Geology

Éléonore is located within the Superior Province of the Canadian Shield, in Northern Quebec. The geological Formations at Éléonore are Archean being roughly 2.7 billion years in age.

Regional Geology

The Éléonore property straddles the contact between the Opinaca meta-sedimentary Sub-province and the Archean La Grande volcano-plutonic Sub-province.  The La Grande Sub-province is composed of 4 volcanic cycles overlain by sedimentary rocks.  The Opinaca Sub-province is composed of a younger sedimentary cycle dominated by paragneiss. The supracrustal rocks of the region are intruded by syn-volcanic, syn-tectonic, and post- or late-tectonic tonalite-trondhjemite-granodiorite suites (TTG).

Geologic studies sporadically distributed in the region show evidence for three deformational events: D1 generated a ~E‑trending foliation, D2 generated a NE- to N-trending foliation, and D3 generated a WNW- to NW-trending non-penetrative fabric.

Regional metamorphic grade varies from greenschist to amphibolite facies and reaches granulite facies near the center of the Opinaca basin. Contact metamorphism found around syn- to post-tectonic intrusions reaches amphibolite grade.

There are evidences for seven different types of mineralized showings in the belt: 1) Zn-rich iron formations; 2) Cu-Au and Cu-Mo porphyries; 3) volcanogenic mineralization; 4) Au-bearing shear zones; 5) Au-rich quartz-carbonate-tourmaline stockworks; 6) spodumene, beryl, and molybdenite pegmatites; and 7) uraniferous migmatites.  The most significant gold showings, aside from Éléonore, are those of the Auclair and Clearwater properties.  At Auclair, gold mineralization is located in the hinge of F2 folds that affect iron formations.  At Clearwater, gold mineralization is concentrated in pre- and/or syn-D2 quartz-tourmaline-calcite veins.

Geological field trip at Éléonore

Local Geology

The Éléonore Property is centered on a discrete tonalite-diorite intrusion, about 10 km in diameter, to the northern margin of a vast batholitic complex and within the contact zone between the La Grande and Opinaca Sub-provinces. The intrusion is bounded by aluminous meta-sediments and conglomerates to the north and south and is in contact with basaltic units and conglomerates to the west. The sedimentary rocks located along the northern edge of the intrusion consist in an assemblage of sandstones/wackes/ conglomerates. The sedimentary rocks evolve into pegmatite-bearing paragneiss to the north and to the west, suggesting a steep metamorphic gradient.

The Roberto Deposit comprises numerous gold zones with the two main ones known as the Roberto and East-Roberto lenses. The Roberto package is located nearby the Ell Lake intrusion and hosted by poly-deformed sedimentary rocks.  The host rock of the mineralized zones is usually a thinly bedded greywacke. The mineralized zones consist of stockworks of quartz-tourmaline-actinolite-arsenopyrite-pyrrhotite veins and veinlets contained within microcline (potassic alteration) and brown tourmaline replacement zones showing variable proportions of disseminated arsenopyrite and pyrrhotite. The structural hanging wall of the mineralized zones is characterized by greywacke containing alumino-silicate porphyroblasts, garnetiferous metasomatic zones, and moderate potassic alteration. The structural footwall of the mineralized zones is characterized by paragneiss units containing high percentage of biotite, pegmatites dykes and quartz veins. Other lithological units found on the property include a polymictic conglomerate (“Timiskaming type”) usually observed near the edge of the Ell Lake intrusion, a highly deformed mafic meta-sedimentary rock unit, graphite-rich chemical sedimentary rocks, and mafic volcanic unit interpreted to be magnesian basalts.

Evidence for three deformational events can be found on the property. The first event (D1) generated a penetrative fabric oriented sub-parallel to bedding that is best developed in paragneiss. Tight to isoclinal asymmetric folds in S0 (Figure 3-8) and local high strain zones can be attributed to that event. The second deformational event (D2) is the most important of the area. It generated a W- to NW-trending penetrative fabric that locally affects alumino-silicate and biotite porphyroblasts.  In the paragneiss, the S2 fabric is locally present as a crenulation cleavage. F2 folds are open asymmetric folds and are best observed on trenches exposing the mineralized zones. The third deformational event (D3) generated folds and fabrics similar to those associated with D2. The S3 foliation is however NE-trending.

Structural analysis performed on the property suggests that gold mineralizing events were ongoing during D2, but could have been initiated as early as D1. Since the intrusion is multiphase and locally affected by S1, the possibility that the Ell Lake intrusion, or parts of it, was temporally coincident with gold mineralization cannot be ruled out.

The Roberto discovery outcrop in 2005