Discovery of large concealed iron deposits beneath low-gradient magnetic anomalies with application of integrated exploration techniques: A case study of Lihuayu iron deposit in Anshan area

Taking the Lihuayu iron deposit beneath low-gradient magnetic anomalies in the Qidashan-Xidabei northsouth iron ore belt of nationally important Anshan iron resource base as the research object, this study successfully identified and delineated a large concealed iron deposit(with the resources of 3.3×10⁸t) buried at depths exceeding 1 000 m through the application of integrated geophysical techniques such as magnetic survey and gravity exploration, combined with geophysical data inversion and borehole verification. The research reveals the formation mechanisms of low-gradient magnetic anomalies and establishes a "trinity" deep prospecting model integrating stratigraphy, structure, and geophysical response. These findings provide a technical demonstration for the deep exploration of Anshan-type sedimentary-metamorphic iron deposits beneath low-gradient magnetic anomalies and can serve as a reference for exploration of similar deposits.