Electrical Structure of Sea-Floor Hydrothermal Sulfide Deposits

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.