Ideal Element Distribution Pattern and Characteristics of Primary Halo in the Fault-Controlled Ore Zone of the Yidinan Gold Deposit, Gansu Province, China

Abstract

A mineral deposit forms because of a combination of complex geologic processes, and this makes it difficult to confirm effectively the presence of ore bodies below the surface. Primary haloes are commonly utilized in mineral exploration as an indicator of the presence of blind ore bodies. Three basic types of zoning occur in primary haloes of mineral deposits, namely axial, longitudinal and transversal. The study of axial zoning is particularly important for deep ore prospecting because it is usually linked to the flow direction of ore-bearing fluids. In this study, multi-element geochemical data were used to analyze the axial variation of primary halos in the Yidinan gold deposit, and a future prospecting target was proposed. A novel method is proposed that combines a correlation matrix and cluster analysis to characterize correlations among various elements. In addition, Gregorian's method was used to calculate the axial zonality series, and the contrast coefficient of the elements on the 14 different elevations of the No. 4 gold-bearing quartz vein was used to study the axial variations of indicator elements. It is proposed that the front halo elements of ore bodies are As, Sb, Bi and Hg, the near-ore halo elements are Au, Ag, Cu, Pb, Zn and Sn, and the tail halo elements are Ti, Co, V, Ni, Mo and W. Finally, based on the zonal concentration of each element and the axial variation of the contrast coefficient of each element with depth, it is speculated that four ore-enrichment regions are present in the No. 4 gold-bearing quartz vein. The study showed that the formation of a primary halo with an ideal element distribution occurred after the establishment of two main metallogenic stages and that other processes that cause strong superimposition of mineralization may occur at depth of the deposit.