Application of the multifractal singular value decomposition for delineating geophysical anomalies associated with molybdenum occurrences in the Luanchuan ore field (China)

Abstract

Abstract Fractal and multifractal scaling can be found in a wide variety of geological, geochemical and geophysical applications, which provide important clues to underlying processes. In this study, the multifractal singular value decomposition (MSVD) method was used to delineate geophysical anomalies associated with Mo mineralizations based on 1:25,000 scale gravity and magnetic data in the Luanchuan super-large molybdenum polymetallic ore district. The results show that: (1) negative gravity anomalies in the Luanchuan ore field have strong spatial relationships with Jurassic granite porphyry bodies associated with porphyry- and skarn-type Mo mineralizations; (2) the uncertainty linked with identifying gravity and magnetic anomalies' areas is correlated with cutoffs defined in the multifractal models, which can be utilized to recognize potential Mo mineralization at depths ranging from 500 m to 2000 m; and (3) positive magnetic anomalies have weak spatial correlations with Jurassic granite porphyry bodies, but are strongly correlated with gabbro and syenite porphyries associated with Fe mineralization, and with the boundary of Jurassic granite porphyry. Compared to the 3-D Jurassic granite porphyry model and the 2.5-D gravity and magnetic inversion plots of the study area, the gravity and magnetic anomalies identified by means of the MSVD method can be integrated to identify potential Mo targets. This application demonstrates that the MSVD method is convenient, simple, rapid, and direct for delineating geophysical anomalies and for outlining potential exploration targets without processing multiple geological, geophysical, and geochemical datasets from disparate sources.