MINERALIZATION CHARACTERISTICS OF THE MULTI-ELEMENT-RICH STRATA IN THE NIUTITANG FORMATION BLACK SHALE SERIES, ZUNYI, GUIZHOU, CHINA

Abstract

Based on a large wealth of systematical analysis data and according to the enrichment coefficients, the mineralizing elements in the multi-element-rich strata of the Niutitang Formation black shale series can be classified as three categories: ⑴super-enriched elements with enrichment coefficients 1000, including Mo,As,Se,Re, etc.; ⑵ strongly enriched elements with enrichment coefficients ranging from 100 to 1000, including Ni,U,Au,Ag,Pt,Pd,Tl, etc.; and ⑶ weakly enriched elements with enrichment coefficients from 5 to 100, including V, Co, Cu, Pb, Zn, Y, Cd, etc. Furthermore, considering the geochemical characteristics and types of the mineralized rocks of the above elements, the authors think the multi-element-rich strata possess- synthetic characteristics of magmatism, hydrothermal sedimentation and mechanical sedimentation, which are the product of deep-seated magmatic activities. The general metallogenic model can be described as bellows: the early magmatic activities are accompanied with hydrothermal sedimentation and the formation phosphorite (and siliceous rocks ), in the middle period, the magmatic activities became weak, as reflected by denudation sedimentation; and in the late period, volcanic explosion led to not only the accumulation of emanation, but also brought about deep-seated metallogenic materials, followed by ore deposition under the action of flowing water through their mechanical enrichment.