Chimneys in Paleozoic massive sulfide mounds of the Urals VMS deposits: Mineral and trace element comparison with modern black, grey, white and clear smokers
MetadataShow full item record
In the Urals, a wide range of well-preserved chimneys are found in VMS deposits, which are associated with ultramafic (Atlantic type: Dergamysh), mafic (Cyprus type: Buribay), bimodal mafic (Uralian type: Yubileynoye, Sultanovskoye, Yaman-Kasy, Molodezhnoye, Uzelga-4, Valentorskoye) and bimodal felsic (Kuroko or Baymak type: Oktyabrskoye, Tash-Tau, Uselga-1, Talgan, Alexandrinskoye) sequences. Chimneys have also been found in the Safyanovskoye deposit (Altay type) that is hosted by intercalated felsic lavas and carbonaceous shales. A combination of geological, mineralogical and trace element data provide a general outline for comparison between chimneys from the Urals deposits and modern vent sites. The chimneys from the Dergamysh deposit show a broad affinity with those from the Rainbow and other vent sites associated with serpentinites of the Mid-Atlantic Ridge. The chimneys from the Buribay deposit are similar to the black smokers of the EPR vent sites including the scarcity of rare minerals. The chimneys from the Urals type of the VMS deposits show some similarities with grey smokers from the Brother Volcano and PACMANUS sites. The chimneys from the Baymak type of the VMS deposits resemble grey and white smokers of the PACMANUS and grey smokers of the Suiyo vent sites. The chimneys from the Safyanovskoye deposit are similar to the black and clear smokers from the Okinawa Trough. Mineral assemblages are controlled by the combination of host rock composition and physico-chemical conditions of the ore-forming processes.Amount of colloform pyrite, isocubanite and pseudomorphic pyrite and marcasite after pyrrhotite decreases in the chimneys across the range from ultramafic and mafic to felsic-hosted deposits and is concomitant with increase in the contents of sphalerite, galena, bornite, fahlores, native gold and barite across this range. The chimneys from the Urals type contain abundant tellurides and sulfoarsenides, while these minerals are rare (except for hessite) in the Baymak type deposits. In the same range, the buffering capacity of host rocks decreases in contrast to the increase in ƒS2 and ƒO2. With the exception of the Safyanovskoye deposit, trace element assemblages in chalcopyrite vary to reflect the host rock: ultramafic (high Se, Sn, Co, Ni, Ag and Au) → mafic (high Co, Se, Mo and low Bi, Au and Pb) → bimodal mafic (high Te, Au, Ag, Bi, Pb, Co, moderate Se, and variable As and Sb) → bimodal felsic (high As, Sb, Mo, Pb, moderate Bi, and low Co, Te and Se). In sphalerite of the same range, the contents of Bi, Pb, Ag, Au and Sb increase versus Fe, Se and Сo. The variations in trace elements in colloform pyrite coincide with these changes. The specific mineral changes in the local ranges from Cu- to Zn-rich chimneys in each VMS deposit are similar to the general changes in the range of host rock classes of the deposits. However, the local T, ƒS2 and ƒO2 changes can broadly be interpreted in terms of contribution of variable oxygenated cold seawater to the subseafloor and seafloor hydrothermal processes.
Showing items related by title, author, creator and subject.
Initial breakup of supercontinent Rodinia as recorded by ca 860–840 Ma bimodal volcanism along the southeastern margin of the Yangtze Block, South ChinaLyu, P.; Li, W.; Wang, Xuan-Ce; Pang, C.; Cheng, J.; Li, X. (2017)Abstract It is considered that mantle plumes play an important role in the breakup of supercontinents, but continental rifting and associated bimodal volcanism often predate mantle-plume magmatism and the major stage of ...
Genesis of the Permian Kemozibayi sulfide-bearing mafic-ultramafic intrusion in Altay, NW China: Evidence from zircon geochronology, Hf and O isotopes and mineral chemistryTang, D.; Qin, K.; Xue, S.; Mao, Y.; Evans, Noreen; Niu, Y.; Chen, J. (2017)Â© 2017 Elsevier B.V. The recently discovered Kemozibayi mafic-ultramafic intrusion and its associated magmatic Cu-Ni sulfide deposits are located at the southern margin of the Chinese Altai Mountain, Central Asian Orogenic ...
Physicochemical processes in the magma chamber under the Black Mountain porphyry Cu-Au deposit, Philippines: Insights from mineral chemistry and implications for mineralizationCao, Mingjian; Hollings, P.; Cooke, D.; Evans, Noreen; McInnes, Brent; Qin, K.; Li, G.; Sweet, G.; Baker, M. (2018)The Black Mountain porphyry Cu-Au deposit in the Baguio district, Northern Luzon (Philippines) is associated with late Miocene to Pliocene intrusive rocks that retain primary crystallization signatures, providing an ...