At Copper Lake, mineralization occurs in a set of sulphide-carbonate fissure veins hosted by fine-grained metasedimentary rocks of the Middle Devonian Guysborough Group. Nova Scotia Department of Natural Resources, Report ME 2005-1, pp. Dating of the sulphide-alteration (pyrite) and phyllic-alteration (muscovite) stages of the ore system utilized the Re-Os and Ar methods, respectively. In this paper, the results of this work are presented and discussed in the context of the possible origin of this IOCG-style mineralization. The results of The Copper Lake area occurs north of the east-trending CCFS which separates the Meguma and Avalon terranes (Fig. The area lies east of a thick sequence of Ordovician– Devonian volcanic and sedimentary rocks that drape part of the Precambrian Antigonish Highlands (Murphy 2002) and is structurally bounded on all sides, which has led to the setting being interpreted to represent a positive flower structure related to dextral movement along the terrane-bounding CCFS to the south (Webster 1998). 1), the area is underlain by rocks of the Middle Devonian Guysborough Group, as constrained by a U-Pb zircon age of 389 Ma reported by Cormier . The stratigraphy is dominated by green- to grey-green siltstone and shale and grey to black laminated siltstone, silty shale, and shale. Both of these rock assemblages are present in drill core from the mineralized zone at Copper Lake (Black 1996; Kontak 2006). On a obtenu, dans le cadre de cette étude, des données géochronologiques supplémentaires de zircon détritique (datation U-Pb de 1634 ± 11,2 Ma) des roches sédimentaires hôtes ainsi que le moment des événements thermiques, situés à environ 370-380 Ma, 350 Ma et Ar et une datation chimique Th-Pb des roches hôtes et de la monazite. La datation Th-Pb de la monazite révèle qu’une mobilité des métaux des terres rares a accompagné la minéralisation.
Dans le secteur du lac Copper, la minéralisation est présente dans un ensemble de filons de fissures remplies de sulfures-carbonates à l’intérieur de roches métasédimentaires à grains fins du groupe du Dévonien moyen de Guysborough. Lithogeochemical and Sm-Nd and U-Pb isotope data from the Silurian–Lower Devonian Arisaig Group clastic rocks, Avalon terrane, Nova Scotia: A record of terrane accretion in the Appalachian-Caledonide orogen.
Collectively, the data indicate that the area experienced multiple thermal events, but hydrothermal activity related to mineralization is constrained to about 320 Ma and is tentatively interpreted to relate to structural focusing of fluids that may have been driven by a mid-crustal level mafic heat source.
The mineralizing event coincides with regional Alleghanian deformation in this part of the Appalachian orogen and thus reflects larger-scale tectonothermal processes.
[Traduit par la redaction] The metallogenic map of Nova Scotia (Chatterjee 1983) shows a high concentration of iron-oxide mineralization and associated base- and precious-metal enrichment proximal to the prominent, east-trending Cobequid-Chedabucto Fault System (CCFS, Fig. Orogenesis and basin development: U-Pb detrital zircon age constraints on evolution of the Late Paleozoic St.
1a) which separates the Avalon and Meguma terranes in this part of the Appalachian orogen. Much of this mineralization is related to widespread carbonate- and iron -oxide alteration (i.e., specular hematite with magnetite absent) regardless of the age or nature of the host rock.