Yu Qinfan, 1989. "Application of Magnetic Anisotropy to Magnetic Anomaly Interpretation in Iron ORE Districts", An Overview of Exploration Geophysics in China — 1988, Zhao Jingxiang, Wang Yanjun, Fu Xuexin, Stanley H. Ward
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The Precambrian sedimentary metamorphic iron ore is a dominant type of ore deposit in China. This type of iron deposit often exhibits magnetic anisotropy. The conventional theory and method used for interpretation of magnetic anomalies under homogeneous magnetization will not meet the needs of magnetic anomaly interpretation for this kind of iron deposit, particularly in the detailed magnetic anomaly interpretation of the prospect evaluation stage.
To study magnetic anisotropy due to stratified texture, 508 samples from Qianan iron district, Hebei Province, were measured. The results show that the degree of magnetic anisotropy P (= K∥/K⊥) is usually 2 to 3, sometimes even up to 10 in the district. Major factors affecting anisotropy, such as magnetite grain size, magnetite layer thickness, and magnetite concentration, are discussed. The magnetic characteristics of semicylinder, antiform, and synform bodies are studied through magnetic simulation tests. A simplified interactive program for the case of magnetic anisotropy has been developed.
The research results presented have been extensively applied in magnetic surveys in the Qianan district. A deeply buried thick orebody has thus been discovered in the district.