Identification of the Ore-Forming Anomaly Component by MSVD Combined with PCA from Element Concentrations in Fracture Zones of the Laochang Ore Field,Gejiu,SW China

Fault and fractures are well-developed in the Gejiu tin-polymetallic district,and they are closely related to the formation and distribution of ores.In this paper,the principal component analysis(PCA)and multifractal singular value decomposition(MSVD)methodologies were applied for identification of the ore-forming anomaly components from element concentrations of fault rocks in the Laochang ore field,Gejiu.The results show that:(1)the wall rocks and fault rocks have anomalous concentrations of ore-forming elements,indicating that these elements are mainly derived from fluid/rock interaction in the fracture zones;(2)PCA based on clr-transformed data was used to recognize significant association anomalies of ore-forming elements,which lay a foundation for further extracting ore-forming anomaly components from the element association anomalies related to Sn-Cu mineralization;(3)MSVD could effectively explore local anomaly features and decompose ore-forming element association anomalies associated with buried mineralization in more detail.The ore-forming element anomaly components can delineate ore-finding Sn-Cu polymetallic deposits more exactly than the ore-forming element association anomalies.