Platinum-group element geochemistry of the volcanic rocks associated with the Jaguar and Bentley Cu–Zn volcanogenic massive sulfide (VMS) deposits, Western Australia: implications for the role of chalcophile element fertility on VMS mineralization

2020 ◽  
Author(s):  
Jung-Woo Park ◽  
Ian Campbell
Keyword(s):  
Western Australia ◽  
Platinum Group Element ◽  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Group Element ◽  
Volcanogenic Massive Sulfide ◽  
Element Geochemistry ◽  
Chalcophile Element ◽  
Vms Deposits

Petrochemistry, hydrothermal alteration, mineralogy, and sulfur isotope geochemistry of the Turgeon Cu–Zn volcanogenic massive sulfide deposit, northern New Brunswick, Canada

2015 ◽  
Vol 52 (4) ◽  
pp. 215-234 ◽  
Author(s):  
Erik Lalonde ◽  
Georges Beaudoin
Keyword(s):  
New Brunswick ◽  
Hydrothermal Alteration ◽  
Hanging Wall ◽  
Massive Sulfide ◽  
Sulfide Deposit ◽  
Trace Element Geochemistry ◽  
Volcanogenic Massive Sulfide ◽  
Element Geochemistry ◽  
Vms Deposits ◽  
Ocean Ridge

The Turgeon deposit is a mafic-type, Cu–Zn volcanogenic massive sulfide (VMS) deposit. It is hosted by Middle Ordovician pillow basalts of the Devereaux Formation of the Fournier Group within the Elmtree-Belledune inlier, near the Bathurst Mining Camp (BMC) in northern New Brunswick, Canada. The Turgeon deposit consists of two Cu–Zn massive sulfide lenses (“100m Zn”, “48-49”) composed of pyrite, chalcopyrite, pyrrhotite, and sphalerite, which are underlain by chalcopyrite–pyrite stockwork veins. Pyrite is overprinted and replaced by chalcopyrite in the stockwork and vent complex sulfide facies, where both minerals are enriched in Se and Co relative to pyrite and chalcopyrite in the massive pyrite and breccia sulfide facies. In, Se, and Co display a positive covariation with Cu, whereas Zn displays a positive covariation with Cd. Trace element geochemistry indicates that the host rocks are primarily tholeiitic basalts and andesites that have signatures between that of mid-ocean ridge basalt and island-arc tholeiite. The hanging wall rhyolite plots as an ocean ridge rhyolite and is geochemically similar to VMS-bearing FIIIa-type rhyolites. Hydrothermal alteration mineral assemblages in the footwall basalts proximal to mineralization are dominantly chlorite ± quartz in the stockwork zone, which is characterized by compositional gains in Fe and Mg and losses in Na and Ca. The chlorite-altered basalts and andesites have undergone up to 35% mass loss. Stockwork chlorite is an Fe-rich chamosite, whereas chlorite in the massive sulfides is a Mg-rich clinochlore. Chlorite geothermometry yields temperatures of 329–361 °C for chamosite and 246–286 °C for clinochlore. Sulfides at Turgeon have an average δ34SCDT of +6.9‰ (range: +5.8‰ to +10‰), indicating that sulfur was mostly derived from thermochemical reduction of Ordovician seawater sulfate. The Turgeon VMS deposit differs from those of the BMC, which is a reflection of their different tectonic settings; but it is similar to other mafic-type VMS deposits, such as the Betts Cove, Tilt Cove, and Rambler VMS deposits in Newfoundland, Canada.

Geochemical constraints on magmatic and metallogenic processes: Iskut River Formation, volcanogenic massive sulfide-hosting basalts, NW British Columbia, Canada

2015 ◽  
Vol 52 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Tony Barresi ◽  
JoAnne L. Nelson ◽  
Jaroslav Dostal
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Massive Sulfide ◽  
High Heat ◽  
Volcanogenic Massive Sulfide ◽  
Northern Half ◽  
Vms Deposits ◽  
Group 2 ◽  
Group 1

Volcanic rocks of the Jurassic Iskut River Formation (IRF) in northwestern British Columbia (Canada) host several volcanogenic massive sulfide (VMS) deposits, including the exceptionally high-grade Eskay Creek Ag–Au–Cu–Pb–Zn deposit. The IRF comprises voluminous pillow basalt (>90%), minor rhyolite, and sedimentary rock of late Early to early Middle Jurassic age, filling a series of sub-basins along a 300 by 50 km north-trending belt. Two geochemically distinct types of tholeiitic basalts interfinger; both resemble back-arc basin basalts formed from the melting of asthenospheric and sub-arc mantle sources. Group 2 basalts are more enriched in light rare-earth elements, Ba, K, Sr, Th, and U, and have lower positive εNd values than group 1 basalts (+3.2 to +6.3 versus +6.9 to +8.4, respectively). The compositional differences between group 1 and group 2 basalts are interpreted to result from crustal contamination in group 2. Group 1 basalts are most common in the southern part of the IRF belt where they are closely associated with the Eskay Creek, Bonanza, and Hidden Creek (Anyox) VMS deposits. Group 2 basalts are most abundant in the northern half of the belt and are not associated with exploited mineral deposits. The lack of crustal contamination in group 1 basalts indicates that they formed from rapidly ascending magma in an advanced rift setting and were associated with high heat flow that drove hydrothermal circulation. Group 1 and group 2 basalts are reliably discriminated by Ta/Th <2.5 in the former and >2.5 in the latter. This geochemical criteria can therefore be used as an exploration tool to identify VMS permissive sub-basins and (or) stratigraphy in the IRF.

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