|
Grevet |
|
|
Quebec, Canada |
| Main commodities:
Zn Cu
|
|
 |
|
|
 |
Super Porphyry Cu and Au
|
IOCG Deposits - 70 papers
|
All papers now Open Access.
Available as Full Text for direct download or on request. |
|
|
The Grevet zinc-copper deposit is located 40 km north-east of the town of Lebel-sur-Quévillon in Quebec, Canada, some 240 km north-east of Rouyn-Noranda.
It comprises a strongly deformed series of massive sulphide lenses within an Archaean volcanic sequence of the Abitibi sub-province within the Superior Province which forms part of the Canadian Shield.
Regionally the host succession is dominated by mafic to felsic volcanics, gabbroic and dioritic intrusives and sediments, all of which have been cut by syn- to late-tectonic granitoid intrusives. The deposit is located within the major 5 km wide, south-east trending Cameron deformation zone in the central part of the Abitibi Belt. This zone cuts across earlier regional fabrics and has a horizontal dextral sense of movement. Its southern margin, 2 km south of the deposit, is defined by an elongate tonalite body. In the immediate deposit area the host sequence is subdivided into four units:
1). a 500 to 600 m thick unit of mafic volcanics, mainly pillowed lavas, with local felsic bands near a minor ore lens,
2). a 200 to 300 m thick felsic package composed of alternating 3 to 15 m thick massive volcanics (lavas ?) and fragmentals,
3). alternating 2 to 7 m thick layers of mafic to felsic lava and volcaniclastics cut by several generations of felsic to mafic dykes, and
4). a concordant intrusive diorite mass, not influenced by the deformation. This is followed by further rocks of the third zone.
Mineralisation occurs as several steeply dipping to vertical sheet like sulphide lenses hosted generally within zone 3 (see the list below for dimensions, tonnages and grades).
The Grevet area is characterised by tectonic fabrics related to the Cameron Deformation Zone, including mylonitic fabric axial planar to isoclinal folds, stretching lineations, boudinage, transposition of earlier structures, dextral shear indicators, late crenulation cleavage, shear fractures and kink bands.
The ore lenses are parallel to the mylonitic foliation, while the main axes of these lenses correspond closely with fold axes and stretching lineations. Three types of sulphide assemblage are noted, as follows: 1). massive sphalerite and pyrite, 2). stringer and breccia sphalerite and pyrite and 3). disseminated pyrite. These three styles are irregularly distributed in each sulphide lens. The ore lenses have been folded, with the breccia and disseminated styles interpretted as being due to tectonic dis-memberment, especially in fold hinges.
The total geologic resource at Grevet is quoted at:
18.5 Mt @ 7.22% Zn, 0.41% Cu, 0.15% Pb, 31.3 g/t Ag.
This includes the following lenses
3 Lens - 11.27 Mt @ 6.51% Zn, 0.31% Cu, 1100x550x4.50 m
4 Lens - 3.33 Mt @ 6.46% Zn, 0.29% Cu, 600x390x3.61 m
97 Lens - 3.38 Mt @ 10.00% Zn, 0.86% Cu, 700x1000x3.4 m
II Lens - 0.50 Mt @ 9.37% Zn, 0.59% Cu, 300x200 m
For detail see the reference(s) listed below.
The most recent source geological information used to prepare this decription was dated: 1993.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
|
|
|
|
Lacroix J, Daigneault R 1993 - Structural evolution of the Grevet Zn-Cu massive Sulfide deposit, Lebel-sur-Quevillon area, Abitibi subprovince, Quebec: in Econ. Geol. v88 pp 1559-1577
|
|
Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
|
Top | Search Again | PGC Home | Terms & Conditions
|
|
