Journal article
Characteristics of Cu isotopes from chalcopyrite-rich black smoker chimneys at Brothers volcano, Kermadec arc, and Niuatahi volcano, Lau basin
HA Berkenbosch, CEJ de Ronde, BT Paul, JB Gemmell
Mineralium Deposita | Published : 2015
Abstract
We analysed primary chalcopyrite from modern seafloor ‘black smoker’ chimneys to investigate high-temperature hydrothermal Cu isotope fractionation unaffected by metamorphism. Samples came from nine chimneys collected from Brothers volcano, Kermadec arc, and Niuatahi volcano, Lau backarc basin. This is the first known study of Cu isotopes from submarine intraoceanic arc/backarc volcanoes, with both volcanoes discharging significant amounts of magmatic volatiles. Our results (n = 22) range from δ65Cu = −0.03 to 1.44 ± 0.18 ‰ (2 sd), with the majority of samples between ∼0.00 and 0.50 ‰. We interpret this cluster (n = 17) of lower δ65Cu values as representing a mantle source for the chimney Cu..
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Funding Acknowledgements
This research was supported by an Australian Research Council Centre of Excellence in Ore Deposits (CODES) research scholarship (University of Tasmania), an AusIMM Bicentennial Gold 88 endowment, and a Society of Economic Geologists Foundation student research grant from the Hugh E. McKinstry Fund, all to H. Berkenbosch. C. de Ronde was supported by public research funding from the Government of New Zealand. We thank S.G. Merle for assistance with Figs. 1 and 2 and T. Seward for helpful insight into Cu complexes. This manuscript was also improved by helpful suggestions from R. Mathur and an anonymous reviewer.