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TitleMetallogeny of the Robb Lake carbonate-hosted zinc-lead district, northeastern British Columbia
AuthorParadis, S; Nelson, J L
SourceMineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods; by Goodfellow, W D (ed.); Geological Association of Canada, Mineral Deposits Division, Special Publication no. 5, 2007 p. 633-654
Year2007
Alt SeriesEarth Sciences Sector, Contribution Series 20070209
PublisherGeological Association of Canada, Mineral Deposits Division (St. John's, NL, Canada)
Documentserial
Lang.English
Mediapaper; DVD
RelatedThis publication is contained in Goodfellow, W D; (2007). Mineral deposits of Canada: a synthesis of major deposit-types, district metallogeny, the evolution of geological provinces, and exploration methods, Geological Association of Canada, Mineral Deposits Division, Special Publication no. 5
File formatpdf
ProvinceBritish Columbia
NTS94B/13
AreaRobb Lake
Lat/Long WENS-124.0000 -123.5000 57.0000 56.7500
Subjectseconomic geology; metallic minerals; tectonics; mineral deposits; mineral occurrences; mineral potential; exploration; mineral exploration; mineralization; lead; zinc; sulphides; sulphide deposits; carbonates; carbonate rocks; metallogeny; mineral deposits genesis; Mississippi Valley deposits; tectonic setting; host rocks; alteration; exploration methods; Robb Lake Deposit; Muncho-McConnell Formation; Dunedin Formation; Stone Formation; Silurian; Devonian; Paleozoic
Illustrationssketch maps; tables; cross-sections; photographs
ProgramConsolidating Canada's Geoscience Knowledge
ProgramTargeted Geoscience Initiative (TGI-3), 2005-2010
AbstractThe Robb Lake Zn-Pb district consists of numerous carbonate-hosted sulphide deposits of the classic Mississippi Valley-type (MVT). Most deposits are hosted by deformed and thrust-faulted Silurian to Middle Devonian platform dolostones of the Muncho-McConnell, Stone, and Dunedin formations, which are found adjacent to the shelf front of the northern Canadian Rocky Mountains. The Robb Lake deposit, the most significant deposit in the district, consists of 19 known stratabound Zn-Pb showings that are hosted in interconnecting bedding-parallel and crosscutting breccia bodies in as much as 200 m of the stratigraphic sequence. The main sulphide minerals are sphalerite, galena, and pyrite, occurring as open-space fillings in breccias, fractures, and vugs, as well as disseminated clusters of crystals that occupy intergranular pore spaces.

The timing of the Robb Lake sulphide mineralization is constrained by paleomagnetism, which gives an Eocene age, and by Rb-Sr isotope data on sphalerite, which suggest a Paleozoic age, although there is a considerable scatter in the results due to heterogeneous 87Sr/86Sr values in primary fluids. Fluid inclusion and isotopic data suggest that sulphide mineralization formed from saline (16 to >23 wt.% NaCl equiv.) NaCl-CaCl2 brines ranging in temperature from 87 to 154°C and that these fluids interacted with adjacent or underlying siliciclastic rocks. Such fluids are commonly linked to deep burial sedimentary and tectonic compaction or to topographic or gravity-driven fluid flow during the Cretaceous-Tertiary Laramide Orogeny. Alternately, the fluids may have originated as hydrothermal solutions channeled along reactivated back-arc intrabasinal faults and permeable stratified units. In such a scenario, MVT mineralization would be the far-field consequence of subduction and slab rollback that took place on the western margin of North America during the Devonian-Mississippian and generated back-arc and intra-arc spreading and related exhalative activity.
GEOSCAN ID224198