title: Rapid growth of mineral deposits at artificial seafloor hydrothermal vents.
abstract: Seafloor massive sulphide deposits are potential resources for base and precious metals (Cu-Pb-Zn ± Ag ± Au), but difficulties in estimating precise reserves and assessing environmental impacts hinder exploration and commercial mining. Here, we report petrological and geochemical properties of sulphide chimneys less than 2 years old that formed where scientific boreholes vented hydrothermal fluids in the Iheya-North field, Okinawa Trough, in East China Sea. One of these infant chimneys, dominated by Cu-Pb-Zn-rich sulphide minerals, grew a height of 15 m within 25 months. Portions of infant chimneys are dominated by sulphate minerals. Some infant chimneys are sulphide-rich similar to high-grade Cu-Pb-Zn bodies on land, albeit with relatively low As and Sb concentrations. The high growth rate reaching the 15 m height within 25 months is attributed to the large hydrothermal vent more than 50 cm in diameter created by the borehole, which induced slow mixing with the ambient seawater and enhanced efficiency of sulphide deposition. These observations suggest the possibility of cultivating seafloor sulphide deposits and even controlling their growth and grades through manipulations of how to mix and quench hydrothermal fluids with the ambient seawater.
authors.affiliation: Research and Development (R&D) Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.|Frontier Research Center for Energy and Resources (FRCER), School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Nozaki
authors.affiliation: Department of Earth and Planetary Sciences, School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Jun-Ichiro
authors.initials: J
authors.lastname: Ishibashi
authors.affiliation: Department of Earth and Planetary Sciences, School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Shimada
authors.affiliation: The Center for Academic Resources and Archives, The Tohoku University Museum, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
authors.forename: Toshiro
authors.initials: T
authors.lastname: Nagase
authors.affiliation: Research and Development (R&D) Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.|Department of Resources and Environmental Engineering, School of Creative Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan.
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Takaya
authors.affiliation: Research and Development (R&D) Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.|Frontier Research Center for Energy and Resources (FRCER), School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.|Department of Systems Innovation, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Research and Development (R&D) Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.|Department of Subsurface Geobiological Analysis and Research (D-SUAGR), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.|Laboratory of Ocean-Earth Life Evolution Research (OELE), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Kawagucci
authors.affiliation: Department of Subsurface Geobiological Analysis and Research (D-SUAGR), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.
authors.forename: Tomoo
authors.initials: T
authors.lastname: Watsuji
authors.affiliation: Research and Development (R&D) Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.|Laboratory of Ocean-Earth Life Evolution Research (OELE), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.
authors.forename: Takazo
authors.initials: T
authors.lastname: Shibuya
authors.affiliation: Department of Earth Science, School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Yamada
authors.affiliation: Center for Deep Earth Exploration (CDEX), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Saruhashi
authors.affiliation: Center for Deep Earth Exploration (CDEX), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Kyo
authors.affiliation: Research and Development (R&D) Center for Submarine Resources, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.|Department of Subsurface Geobiological Analysis and Research (D-SUAGR), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.|Laboratory of Ocean-Earth Life Evolution Research (OELE), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka, Kanagawa 237-0061, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Takai