Extraction of Gravity–Magnetic Anomalies Associated with Pb–Zn–Fe Polymetallic Mineralization in Luziyuan Ore Field, Yunnan Province, Southwestern China

Abstract

The method of bi-dimensional empirical mode decomposition (BEMD) and the combined methods of entropy weight-Technique for Order of Preference by Similarity to an Ideal Solution (TOPSIS) were used to decompose gravity-magnetic data and evaluate targets in the Luziyuan Pb-Zn-Fe polymetallic ore field and surrounding areas. Three meaningful bidimensional intrinsic mode function (BIMF) images were obtained by BEMD at different wavelengths, depicting different layers of geological architectures in the study area. The results are as follows. (1) The BIMF2 images depict the shallow local geological architecture and show positive gravity-magnetic anomalies of the skarn alteration and Pb-Zn-Fe mineralization distributed around concealed granites. (2) The BIMF3 images depict the medium-depth geological architecture, indicating that concealed granitic stocks, which are shallow extensions of a deeply concealed pluton, intruded along the NE-trending fault. (3) The BIMF4 images depict gravity-magnetic anomalies at greater depth, which likely reflect regional geological architectures, indicating the potential presence of a large, concealed intermediate-acid pluton in the negative anomaly zone. Three potential targets (A, B, and C) were delineated based on BEMD results of the original gravity-magnetic data. The entropy weight-TOPSIS evaluation results show that the ranking of the metallogenic potential of the delineated targets in the study area is B, A, and C, with relative proximity values of 0.4576, 0.3925, and 0.1499, respectively. The results of this study can be used to guide future exploration.

Identifying Multi-Scale Gravity and Magnetic Anomalies Using Statistical Empirical Mode Decomposition: A Case Study from the Eastern Tianshan Orogenic Belt

“…In these methods, EMD has been increasingly applied as a data-driven approach for decomposing complex gravity and magnetic signals due to its strong adaptability to nonlinear and nonstationary data. This is because it defines and utilizes intrinsic mode functions (IMFs) to isolate a given signal according to the local oscillation magnitude in the physical domain [18][19][20][21][22][23][24][25]. For instance, Huang et al [26] used the bidimensional EMD (BEMD) method to handle the gravity data of a gold field, which yielded IMF maps depicting the spatial distribution relationship between gold deposits and the geological units; Chen et al [27] decomposed gravity and magnetic signals using the BEMD method to extract the local anomalies that indicate exploration targets; Hou et al [28] applied BEMD to separate the magnetic anomalies associated with silver, lead, and zinc polymetallic deposits from a regional field; Zhao et al [29] developed an improved BEMD method and used it to characterize the multi-scale anomalies of aeromagnetic survey data; Chen et al [30] employed BEMD to extract the gravity anomaly indicating the ore-controlling geological factors and granites in a tin-copper polymetallic ore field; Asl and Manaman [31] proposed to utilize the modified EMD method for locating magnetic bodies by extracting the IMFs of the magnetic data; and Animesh and Shankho [32] applied BEMD in delineating gravity signatures related to complex near-surface features from noisy gravity data.…”

Evaluation of Community Disaster Resilience (CDR): Taking Luoyang Community as an Example

“…is method has been widely used in urban research [40], sustainable development research [41], tourism research [42], supply chain research [43], food security [44], industrial design [45], and other fields [46,47]. ere are also many applications in the field of disaster science.…”