Abstract:
Objective To address the challenges of deep and peripheral exploration for sedimentary-metamorphic iron deposits in the Anshan–Benxi area, this study focuses on the difficulty of identifying relatively low-amplitude ore-related aeromagnetic anomalies under a high aeromagnetic background. A method for identifying and locating concealed iron ore bodies constrained by high magnetic background was established, providing technical support for prospecting breakthroughs of concealed iron deposits in the Anshan–Benxi area.
Methods This study takes the No.1 and No.2 mining areas of the Gongchangling iron deposit as research objects. After systematically analyzing geological and geophysical prospecting indicators, an integrated geological–geophysical prospecting prediction model was constructed. Based on the model, a low-amplitude aeromagnetic anomaly zone on the periphery of the No.1 mining area was selected to carry out high-precision ground magnetic surveys. With geological constraints, forward and inverse modeling and fitting analysis were performed on large-scale magnetic profile data to accurately identify concealed iron ore bodies.
Results Prospective areas and priority prospecting targets were delineated in the Gaojiagou area south of the No.1 mining area. The concealed iron ore bodies were identified and located, followed by drilling verification. The results show that multiple concealed iron ore bodies occur at depth in the southern part of the No.1 mining area. Their burial depths range from 168 m to 350 m, with a cumulative thickness greater than 120 m, and the estimated iron ore resources exceed 10 million tons.
Conclusions The integrated geological–geophysical prospecting model and multi-method coupling technique proposed in this study can effectively identify concealed iron ore bodies corresponding to low-amplitude aeromagnetic anomalies under high magnetic background, achieving a breakthrough in deep and peripheral prospecting and discovering a medium-sized iron deposit. This method is practical and effective and can provide a reference for the exploration of similar iron deposits in the Anshan–Benxi area.
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