GEOSCAN, résultats de la recherche


TitreVolcano-stratigraphic relationships, lithogeochemistry, and structural analysis of the 1807 zone, Ming Mine, Baie Verte Peninsula, Newfoundland
AuteurPilote, J -L; Piercey, S J; Pilgrim, L; Legrow, P
SourceAssociation géologique du Canada-Association minéralogique du Canada, Réunion annuelle, Programme et résumés vol. 36, 2013 p. 163
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130547
RéunionGAC-MAC 2013; Joint annual meeting of Geological Association of Canada and Mineralogical Association of Canada; Winnipeg; CA; mai 22-24, 2013
Documentpublication en série
Lat/Long OENS-56.1397 -56.0217 49.9317 49.8658
Sujetsgîtes minéralogiques; gisements minéraux; minéralisation; cuivre; or; zinc; gîtes volcanogènes; sulfures; gîtes sulfureux; déformation; Groupe de Pacquet Harbour ; géologie économique; stratigraphie; Paléozoïque; Ordovicien
ProgrammeÉtude des gîtes de sulfures massifs volcaniques, Initiative géoscientifique ciblée (IGC-4)
LiensOnline - En ligne
Résumé(disponible en anglais seulement)
The Ming Cu-Zn-Au-Ag Ming volcanogenic massive sulfide deposit (10.6 Mt) is part of the Rambler mining camp, located in the upper ophiolitic sequence of the Baie Verte Oceanic Tract, northern Notre Dame subzone. The deposit is hosted by intermediate to felsic volcanic and volcaniclastic rocks of the early Ordovician (ca. 487 Ma) Pacquet Harbour Group, which is part of a regional mafic-dominated rock assemblage of boninitic to tholeiitic affinity. By means of systematic detailed underground mapping and diamond drill-hole description, the purpose of this study is to characterize the stratigraphy, primary and secondary lithogeochemistry, and structure of the Ming Mine. The 1807 zone consists of a Cu-Zn-Au-rich massive sulfide horizon hosted by a sequence of dacitic to rhyolitic quartz-phyric tuff, lapilli tuff, and tuff breccia. It is structurally to disconformably overlain by a mafic-dominated subaqueous volcanic sequence, including minor magnetite-rich horizons and mafic to intermediate epiclastic rocks. Immediate footwall alteration includes chlorite + quartz + sericite ± biotite ± calcite ± epidote, with zones of quartz + sericite ± fuchsite, whereas the deeper (~100 m below the massive sulfide) footwall contains only chlorite + quartz alteration. The massive sulfide horizon in the 1807 zone shows evidence of remobiliza tion during compressional deformation and contain a NE-SW trending axial plane with a shallow plunging 030°N trending mineral lineation. These folds transpose an early predominant E-W discrete shear fabric with crenulation lineation steeply to shallowly plunging WNW. Overall, the deposit consists of parallel elongated shallow plunging lenses trending NE, named (from NW to SE) the 1807 zone, 1806 zone, Ming South, and Ming North. In addition, at least two generations of mafic to intermediate dykes are present; 1) a syn-kinematic (high Zr/TiO2) suite deformed within the massive sulfide; and 2) texturally and compositionally different (low Zr/TiO2) mafic dykes, interpreted as pre-sulfide deformation with magmatic contact relationships. The latter dykes may have played a significant role during deformation of the massive sulfide by thickening and controlling sulfide distribution due to differences in rock competency. Ongoing research will increase confidence and resolution on the stratigraphy and test the hypothesis of a close structural relationship between the dykes and remobilization of the massive sulfide. Hence, studying the 1807 zone will provide a better understanding on the evolution of the Ming deposit and also has implications on the tectonic evolution of the Baie Verte Peninsula.