深海热液金属硫化物矿电性结构
Electrical Structure of Sea-Floor Hydrothermal Sulfide Deposits

深海热液金属硫化物矿位于水深数千米的大洋洋底，其形态、规模及电性参数难为人知，迄今尚未有由实测数据推导其电性结构的研究.依托于“大洋一号”，在大西洋洋中脊、西南印度洋洋中脊实施了多次深海热液金属硫化物矿探测试验，实地采集热液金属硫化物矿瞬变电磁响应数据，并对试验数据进行反演分析.分析表明：大西洋TAG(trans-Atlantic geotraverse)热液区及西南印度洋49°4′E，37°5′S热液区内，深海热液金属硫化物矿形似生长于洋壳内的“蘑菇”，矿体呈透镜状或似层状结构，分布于热液喷口的卤水池内，电阻率约为0.1Ω·m，规模为50～250 m，厚度范围为20～50 m；热液烟囱直径为10～50 m，周围岩石发生热液蚀变，蚀变岩石电阻率在0.2～0.5 Ω·m，以热液通道为中心呈圈层状变化.依据深海热液金属硫化物矿的形态特征及电性参数，矿体的电性结构模型可简化为T型异常体.
The deep sea hydrothermal metallic deposits are located on seafloor at depth about several kilometers, and it is difficult to determine their shape, scale and electrical parameters, and the electrical structure based on field data remains unknown. Using research vessel “DaYang-Ⅰ”, several detection tests were implemented at Atlantic ridge and Southwest Indian ridge, and the electromagnetic response data of deep-sea hydrothermal metallic sulfide deposits have been observed and analyzed. The analysis show that in the Atlantic TAG (trans-Atlantic geotraverse) hydrothermal area and Southwest Indian Ocean 49°4′E, 37°5′S hydrothermal area, deep-sea hydrothermal metallic sulfide deposits are like‘mushroom’ in the oceanic crust, located in the brine pool around the hydrothermal vents with lenticular structure or stratoid structure, the resistivity is about 0.1 Ω·m, the scale changes from 50 to 250 m, and the thickness is from 20 to 50 m. The diameter of hydrothermal channel ranges from 10 to 50 m，and hydrothermal alternation took place within and outside the hydrothermal channel. The resistivity of the alternation rocks is in the range of 0.2 to 0.5 Ω·m, and concentrically changes around the hydrothermal channel. Based on the shape and electrical parameters of hydrothermal metallic sulfide deposits, the ore body can be simplified as a T-shaped target for electrical structure model