A comparative study on polymetallic metallogenic characteristics of Xiangshan and Lengshuikeng ore fields

More than 20 uranium deposits and polymetallic mineralization have been discovered in the Xiangshan ore field at present. However, breakthroughs in polymetallic prospecting are yet to be made in the ore field.This paper compared the Xiangshan ore field with the Lengshuikeng lead-zircon-silver polymetallic ore field at a high exploration level in terms of regional geological setting, strata, magmatic rocks, ore body characteristics, and wall-rock alteration. Based on this, it is found that the Xiangshan and Lengshuikeng ore fields are similar in geological conditions, the geochemical characteristics of rare earth elements (REEs) and trace elements, and the characteristics of ore bodies and alternation. Regarding lithology, both are mainly composed of volcanic rock series of the Cretaceous Ehuling and Daguding formations, which are present as high high-K calc-alkaline basalts and possess quasi-aluminous-weakly peraluminous characteristics. The REE-distribution patterns and trace element spider diagrams of the two ore fields are notably rightward, indicating the enrichment of light REEs, low content of Ba and Sr, and obvious Eu depletion. Therefore, the sediments in the two ore fields mainly originate from the crust. Meanwhile, the magmatic rocks feature a high crystallization differentiation degree, and the wall-rock alteration is dominated by chloritization, sericitization, silicification, and carbonation.By referring to the metallogenic model of the Lengshuikeng ore field, it is considered that the future polymetallic prospecting in the Xiangshan ore field should focus on the porphyry-type polymetallic ore in small rock masses and strata-bound, superimposed polymetallic ore at the K₁d¹ horizon. In this manner, breakthroughs are expected to be made in polymetallic prospecting in the Xiangshan ore field.