Zinc-rich Pyrite from the TAG Active Mound, the TAG Hydrotherma Field, Mid-Atlantic Ridge |
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| Authors: | Su Young Lee Masatsugu Ohnishi Yasuhiro Shibata Makoto Wwatanabe Kenichi Hoshino Mayumi Jige Xiangping Gu Hitoshi Chiba Tamotsu Oomori Kantaro Fujioka Peter A Rona |
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| Institution: | Department of Earth and Planetary Sciences, Hiroshima University, Hiroshima 739–8526, Japan [e-mail (MW): ];Institute for Study of the Earth's Interior, Okayama University, Tottori 682-0193, Japan;Department of Chemistry, Biology &Marine Sciences, University of Ryukyus, Okinawa 930-0129, Japan;Japan Marine Science and Technology Center (JAMSTEC), Kanagawa 237-0061, Japan;Institute of Marine &Coastal Sciences and Department of Geological Sciences, Rutgers University, New Jersey 08901-8521, USA |
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| Abstract: | Abstract: Pyrite rich in Zn, up to 3.1 wt%, was found in the TAG active mound of the TAG hydrothermal field, the slow-spreading Mid-Atlantic Ridge at 26°08'N and 44°49'W. The Zn-rich pyrite is characterized by an optical homogeneity, a homogeneous distribution of Zn in the back-scattered electron images, both at a magnification of about 500, a negative correlation between Fe and Zn contents of the pyrite and a rather small unit cell edge (a0 = 5.4117 ± 0.0008Å), strongly indicating that the detected Zn is present in the pyrite in solid solution. Such Zn concentrations are observed exclusively in dendritic pyrite, suggesting that the Znrich pyrite grew from hydrothermal fluids of a high degree of supersaturation due to quenching on the seafloor. |
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| Keywords: | Zn-rich pyrite dendritic growth texture solid solution TAG active mound TAG hydrothermal field Mid-Atlantic Ridge |
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