Application of magnetic potential field transformation in exploration of iron deposits with atypical magnetic anomaly

In Liaoning region, where the geomagnetic inclination is approximately 60°, the magnetic data interpretation has traditionally relied primarily on total field magnetic anomalies (ΔT) or vertical component anomalies (ΔZ). However, for gently dipping iron orebodies, these anomalies are only present over the upper parts(ore heads) of the deposits. Based on demagnetization calculations for Anshan-type iron deposits, it is found that the magnetization direction of non-southward gently dipping orebodies shifts significantly towards the direction parallel to the bedding plane(horizontal direction). Consequently, using the magnetic potential field transformation, the geomagnetic profile ΔT anomalies were converted into ΔH anomalies, and weak ΔH anomalies were revealed over the main parts of gently dipping orebodies, precisely where ΔZ and ΔT show no significant anomalies. Therefore, the transformed ΔH anomaly can be utilized to qualitatively delineate the extent of these gently dipping orebodies. The successful application of this method in practical exploration has demonstrated positive results.