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The T iger Sulfide Chimney, Y onaguni K noll IV Hydrothermal Field, S outhern O kinawa T rough, J apan: The First Reported Occurrence of P t– C u– F e‐Bearing Bismuthinite and S n‐Bearing Chalcopyrite in an Active Seafloor Hydrothermal System
Author(s) -
Gena Kaul,
Chiba Hitoshi,
Kase Katsuo,
Nakashima Kazuo,
Ishiyama Daizo
Publication year - 2013
Publication title -
resource geology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 43
eISSN - 1751-3928
pISSN - 1344-1698
DOI - 10.1111/rge.12015
Subject(s) - chalcopyrite , hydrothermal circulation , sulfide , geology , electron microprobe , pyrite , mineralogy , geochemistry , materials science , metallurgy , copper , seismology
A sulfide chimney ore sampled from the flank of the active T iger vent area in the Y onaguni K noll IV hydrothermal field, south O kinawa trough, consists of anhydrite, pyrite, sphalerite, galena, chalcopyrite and bismuthinite. Electron microprobe analysis indicates that the chalcopyrite contains up to 2.4 wt% S n, whereas bismuthinite contains up to 1.7 wt% P t, 0.8 wt% C u and 0.5 wt% F e. The S n‐rich chalcopyrite and P t– C u– F e‐bearing bismuthinite are the first reported occurrence of such minerals in an active submarine hydrothermal system. The results confirm that S n enters the chalcopyrite as a solid solution towards stannite by the coupled substitution of S n 4+ F e 2+ for F e 3+ F e 3+ , whereas P t, C u and F e enter the bismuthinite structure as a solid solution during rapid nucleation. The fluid inclusions homogenization temperatures in anhydrite (220–310°C) and measured end‐member temperature of the vent fluids on‐site (325°C) indicate that S n‐bearing chalcopyrite and P t– C u– F e‐bearing bismuthinite express the original composition of the minerals that precipitated as metastable phases at a temperature above 300°C. The result observed in this study implies that sulfides in ancient volcanogenic massive sulfide deposits have similar trace element distribution during nucleation but it is remobilised during diagenesis, metamorphism or supergene enrichment processes.