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TitleVolcanostratigraphy of the 1807 zone of the Ming Cu-Au volcanogenic massive-sulphide deposit, Baie Verte Peninsula, northern Newfoundland
AuthorPilote, J -L; Piercey, S J
SourceGeological Survey of Canada, Current Research (Online) no. 2013-20, 2013, 17 pages, (Open Access)
PublisherNatural Resources Canada
Mediaon-line; digital
RelatedNRCan photo(s) in this publication
File formatpdf
ProvinceNewfoundland and Labrador
AreaBaie Verte Peninsula
Lat/Long WENS-56.1397 -56.0217 49.9317 49.8658
Subjectseconomic geology; stratigraphy; mineral occurrences; mineral deposits; mineralization; copper; gold; zinc; volcanogenic deposits; sulphides; sulphide deposits; deformation; Ming Mine; Rambler Mining Camp; Pacquet Harbour Group; Paleozoic; Ordovician
Illustrationslocation maps; stratigraphic columns; photographs; photomicrographs
ProgramTargeted Geoscience Initiative (TGI-4), Volcanogenic Massive Sulfide Ore Systems
Released2014 01 16
AbstractThe Ming Cu-Au volcanogenic massive-sulphide deposit (3.65 Mt at 2.26 wt % Cu, 1.13 g/t Au, 6.78 g/t Ag, and 0.32 wt % Zn) located in the Rambler mining camp 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. The deposit consists of four parallel, elongated, shallowly plunging 030°N lenses, of which the 1807 zone is currently being mined. The 1807 zone consists of a Cu-Zn-Au-rich massive-sulphide horizon hosted by a sequence of aphanitic to quartz-phyric, dacitic to rhyolitic tuff, lapilli tuff, and tuff breccia. It is structurally to disconformably overlain by a mafic-dominated subaqueous volcanic sequence comprised of mafic to intermediate volcaniclastic to epiclastic rocks. The immediate footwall rocks are hydrothermally altered to chlorite+quartz+sericite±calcite±epidote, with zones of quartz+sericite±green mica, whereas the deeper (~100 m below the massive sulphide) footwall rocks are altered to chlorite+quartz.
The massive-sulphide horizon in the 1807 zone shows evidence of deformation and possible remobilization during a regional compressional deformation. Structural modifications include regional-scale anticlinal and micro- to meso-scale tight folds with a northeast-southwest-trending axial plane with a shallow-plunging 030°N trending mineral lineation. In addition, three generations of mafic to intermediate dykes are recognized with the latest presenting features, indicative of a close temporal relationship with the remobilization of the sulphide horizons.
Summary(Plain Language Summary, not published)
The Ming base (Cu, Zn, Pb) and precious (Au and Ag) metal-rich deposit, which is part of the Rambler mining district located in Newfoundland, is associated with a series of volcanic units that were emplaced at the early Ordovician, about 487 million years ago. The study of these volcanic units indicate that there are distinct types of rocks in the deposit footwall and hanging wall and that these volcanic rocks have a different history and played a role in the formation of the deposit. The volcanic rocks in the footwall (below the ore lenses) were altered by ore-bearing fluids and were cut by intrusive rocks (dykes) during volcanism and also during later tectonic activity. This tectonic activity is responsible for the deformation of the ore lenses and the host volcanic rocks and controls the current geometry of the deposit.