Geomagnetic Models and Edge Recognition of Hydrothermal Sulfide Deposits at Mid-ocean Ridges

Abstract

Near-bottom magnetic prospecting is considered to be an efficient method for investigating inactive hydrothermal areas and the study of the spatial structure of hydrothermal systems. Furthermore, geophysical forward modeling is widely used to simulate the anomalous characteristics of geological bodies. To understand the magnetic and magnetic structure features of hydrothermal sulfide deposits at mid-ocean ridges, we built 3D forward models for both mafic- and ultramafic-hosted hydrothermal sulfide deposits to simulate the near-bottom magnetic field. Our modeling results showed a low amplitude magnetic anomaly above the mafic-hosted hydrothermal sulfide deposits, and a high amplitude magnetic anomaly above the ultramafic-hosted deposits. These features allow us to identify and classify the host rocks of hydrothermal sulfide deposits. Moreover, we can recognize the edge of the magnetic anomalies using the intensity of the spatial differential vector method, considering variables such as the width of the alteration zone, the height of the observation platform, and the magnetic inclination and declination. Therefore, we propose the intensity of the spatial differential vector method as an effective approach to define the boundaries of hydrothermal sulfide deposits.

Keywords:

• edge recognition
• forward modeling
• geomagnetic model
• hydrothermal sulfide
• ISDV

Acknowledgements

We thank the National Basic Research Program of China (973 Program) under contract No. 2012CB417305, the national High_Technique R&D Program (863 Program) under contract No. 2011AA09A102, and COMRA Major Project under contract No. DY125-11-R-01-05 for all financial support. Roy Wilkens, University of Hawaii, contributed useful editorial comments.