Rapid growth of mineral deposits at artificial seafloor hydrothermal vents.
Rapid growth of mineral deposits at artificial seafloor hydrothermal vents.
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DOI：
10.1038/srep22163
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发表时间：
2016-02-25
影响因子：
4.6
通讯作者：
Takai K
中科院分区：
文献类型：
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作者：
Nozaki T;Ishibashi J;Shimada K;Nagase T;Takaya Y;Kato Y;Kawagucci S;Watsuji T;Shibuya T;Yamada R;Saruhashi T;Kyo M;Takai K
海底块状硫化物矿床是贱金属和贵金属（铜-铅-锌±银± Au）的潜在资源，但难以估计精确储量和评估环境影响，阻碍了勘探和商业开采。本文报道了中国东海冲绳海槽Iheya-North气田科学钻孔热液喷口处形成的硫化物烟囱的岩石学和地球化学性质。这些婴儿烟囱，主要是铜铅锌丰富的硫化物矿物，增长了15米的高度在25个月内。部分新生烟囱主要由硫酸盐矿物组成。一些新生烟囱富含硫化物，类似于陆地上的高品位Cu-Pb-Zn矿体，但As和Sb浓度相对较低。在25个月内达到15米高度的高增长率归因于钻孔形成的直径超过50厘米的大型热液喷口，这导致与周围海水缓慢混合，提高了硫化物沉积的效率。这些观察结果表明，有可能培育海底硫化物矿床，甚至通过操纵如何将热液流体与周围海水混合和淬火来控制其生长和品位。
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.