Marine Mineral Exploration With Controlled Source Electromagnetics at the TAG Hydrothermal Field, 26°N Mid-Atlantic Ridge
Marine Mineral Exploration With Controlled Source Electromagnetics at the TAG Hydrothermal Field, 26°N Mid-Atlantic Ridge
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DOI：
10.1029/2019gl082928
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发表时间：
2019-06-16
影响因子：
5.2
通讯作者：
Murton, B. J.
中科院分区：
文献类型：
--
作者：
Gehrmann, R. A. S.;North, L. J.;Murton, B. J.
为了满足全球金属需求的持续增长，海底块状硫化物（SMS）矿床的经济利益日益增加。位于北纬26度的大西洋中脊上的跨大西洋地平面（TAG）热液区有几个这样的矿床。这项研究提出了新的可控源电磁、测深和磁场的结果。根据高分辨率测深数据中的表面表达式选择潜在的SMS目标。高分辨率降极磁数据显示SMS矿床下方和周围的负异常，揭示了大面积的热液蚀变。可控源电磁数据，对SMS矿化的电导率敏感，进一步揭示了最大厚度可达80 m，电导率可达5 S/m。SMS样品的电导率高达每米几千西门子，这表明远程推断的电导率代表了金属硫化物矿石与硅化和蚀变的主玄武岩相结合的平均值，可能在更深的深度占主导地位。
Seafloor massive sulfide (SMS) deposits are of increasing economic interest in order to satisfy the relentless growth in worldwide metal demand. The Trans-Atlantic Geotraverse (TAG) hydrothermal field at 26 degrees N on the Mid-Atlantic Ridge hosts several such deposits. This study presents new controlled source electromagnetic, bathymetric, and magnetic results from the TAG field. Potential SMS targets were selected based on their surface expressions in high-resolution bathymetric data. High-resolution reduced-to-the-pole magnetic data show negative anomalies beneath and surrounding the SMS deposits, revealing large areas of hydrothermal alteration. Controlled source electromagnetic data, sensitive to the electrical conductivity of SMS mineralization, further reveal a maximum thickness of up to 80 m and conductivities of up to 5 S/m. SMS samples have conductivities of up to a few thousand Siemens per meter, suggesting that remotely inferred conductivities represent an average of metal sulfide ores combined with silicified and altered host basalt that likely dominates at greater depths.