Internal Structure of a Seafloor Massive Sulfide Deposit by Electrical Resistivity Tomography, Okinawa Trough
Internal Structure of a Seafloor Massive Sulfide Deposit by Electrical Resistivity Tomography, Okinawa Trough
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DOI：
10.1029/2019gl083749
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发表时间：
2019-10
影响因子：
5.2
通讯作者：
K. Ishizu;T. Goto;Y. Ohta;T. Kasaya;H. Iwamoto;C. Vachiratienchai;W. Siripunvaraporn;T. Tsuji;H. Kumagai;K. Koike
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作者：
K. Ishizu;T. Goto;Y. Ohta;T. Kasaya;H. Iwamoto;C. Vachiratienchai;W. Siripunvaraporn;T. Tsuji;H. Kumagai;K. Koike
虽然海底块状硫化物（SMS）矿床是极其重要的金属资源，含有铜，铅和锌等高品位金属，但其内部结构和生成机制仍不清楚。本研究使用深拖海洋电阻率层析成像技术，获得了日本西南部冲绳外热液区电阻率的详细近海底图像。该图像澄清了一个半层状电阻率结构，解释为暴露在海底的SMS沉积物，以及另一个位于海底以下约40米深处的深层SMS层。这些图像加强了我们对SMS演化新机制的推断：上涌热液流体被困在渗透性较低的盖层下。更深层次的嵌入式SMS在那里积累。然后，热液流体排出到海底形成暴露的SMS矿床。
Although seafloor massive sulfide (SMS) deposits are crucially important metal resources that contain high‐grade metals such as copper, lead, and zinc, their internal structures and generation mechanisms remain unclear. This study obtained detailed near‐seafloor images of electrical resistivity in a hydrothermal field off Okinawa, southwestern Japan, using deep‐towed marine electrical resistivity tomography. The image clarified a semi‐layered resistivity structure, interpreted as SMS deposits exposed on the seafloor, and another deep‐seated SMS layer at about 40‐m depth below the seafloor. The images reinforce our inference of a new mechanism of SMS evolution: Upwelling hydrothermal fluid is trapped under less‐permeable cap rock. The deeper embedded SMS accumulates there. Then hydrothermal fluids expelled on the seafloor form exposed SMS deposits.