3D transient electromagnetics forward modeling with complex topography and structure: A case study of the TAG hydrothermal field, Mid-Atlantic Ridge

Nie Zuofu; Tao Chunhui; Shen Jinsong; Zhu Zhongmin

doi:10.12284/hyxb2021086

Volume 43 Issue 6

Jun. 2021

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Nie Zuofu，Tao Chunhui，Shen Jinsong, et al. 3D transient electromagnetics forward modeling with complex topography and structure: A case study of the TAG hydrothermal field, Mid-Atlantic Ridge[J]. Haiyang Xuebao，2021, 43(6)：145–156 doi: 10.12284/hyxb2021086

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3D transient electromagnetics forward modeling with complex topography and structure: A case study of the TAG hydrothermal field, Mid-Atlantic Ridge

doi: 10.12284/hyxb2021086

Nie Zuofu^1
,,
Tao Chunhui^{1, 2, 3
,
,},
Shen Jinsong^{4
,
,},
Zhu Zhongmin⁴

1.
School of Oceanography, Shanghai Jiao Tong University, Shanghai 200240, China
2.
Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
3.
Key Laboratory of Submarine Geoscience, Ministry of Natural Resources, Hangzhou 310012, China
4.
College of Geophysics, China University of Petroleum (Beijing), Beijing 102249, China

Received Date: 2020-07-24
Rev Recd Date: 2020-12-04

Available Online: 2021-04-25

Publish Date: 2021-06-30

Abstract

Abstract

It is crucial to evaluate seafloor massive sulfides (SMS) in terms of their special distribution. Transient electromagnetic method (TEM) is ideal for land mineral deposits prospecting, but the complicated seafloor topography, inner structure of sulfide deposits and measuring conditions in the hydrothermal field pose a great challenge to its application in the ocean. In order to verify the application potential of TEM in deep-sea exploration, a 3D forward modeling scheme was developed with finite element method, combining with bathymetry data and drilling results. The method was then applied to the TAG hydrothermal field, Mid-Atlantic Ridge, and the result was well fitted with acquired TEM data. By comparing the forward simulation results under different instrument positions, attitudes and altitude, we found that the coincident loop system could effectively detect the active TAG mound ore body when the altitude was less than 60 meters. Complex seafloor topography and how the instrument was being towed could significantly disturb the early time response, while the instrument attitude also made an influence on the detected signal. Therefore, it was necessary to combine the bathymetry data, instrument positioning data and attitude data in the research area to better interpret the measured TEM responses.
- transient electromagnetics,
- 3D forward modeling,
- TAG hydrothermal field,
- seafloor massive sulfides,
- complex topography and structure

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References(34)

References

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