Research On The Mineralization Zonation Of High-K Calc Alkaline Intrusive Rocks In Tongling Area

Anhui Tongling is a set of important copper-gold polymetallic ore concentration area in the middle and lower reaches of the Yangtze river copper-iron-sulphur-gold metallogenic belt.These copper-gold polymetallic deposit are closely related to Yanshanian small and medium-sized high-K calc-alkaline intrusions in space and origin,surrounding the rock mass showed the regularity of mineralization zoning.The zoning is not only in terms of ore-forming temperature and element combination,but also on the change of the ore deposit,metallogenic mechanism.Therefore,the study of ore deposit metallogenic zoning and alteration features have important theoretical and practical significance to explore a symbiotic relationship,metallogenic series and metallogenic system,metallogenic model,determine deposit genetic types and formation mechanism,carrying out metallogenic prediction.In this paper,High-K calc-alkaline intrusions in Tongling area,and its associated with Shizishan ore field and Yaojialing deposit are the main research object,by using a variety of modern testing technology and methods to find out the high-K calc-alkaline intrusions distribution form,and make its solid model diagram;and to find out the high-K calc-alkaline intrusions associated with deposits and the spatial distribution characteristics of alteration belt,ore-forming elements zoning laws of space and time,the ore-forming geochemical characteristics of rock mass and its contribution to the mineralization.The Tongling area high-K calc-alkaline intrusions mineralization zoning model is summed up as that: the mineralization type in the vertical,from deep to shallow followed by porphyry deposit ? skarn type deposit ? middle-low temperature hydrothermal type deposit;On the horizontal direction,from rock mass to surrounding rock followed by porphyry deposit ? skarn type deposit ? middle-low temperature hydrothermal type deposit.Ore mineral also exist obvious zoning phenomenon,from bottom to top: chalcopyrite ? pyrrhotite ? containing golden copper(iron)ore ?lead-zinc ore;from rock mass to surrounding rock followed by chalcopyrite?pyrrhotite?containing golden copper(iron)ore?lead-zinc ore.Also,ore-forming elements exist obvious zoning phenomenon,from bottom to top: Cu(Au)?Cu,Au?Au,Cu?Au;From the rock mass center to the surrounding rock: Cu(Au)?Cu,Au?Au(Cu)?Ag,Au,Pb,Zn.A comparative study of combining iron,sulfur and lead isotopic compositions,found that the ore-forming elements of the deposit are mainly derived from magma or magmatic hydrothermal.From nearly rock mass skarn to the skarn type ore body to close to the surrounding rock magmatic hydrothermaltype ore body,Fe isotopic composition of different locations as far away from the rock mass containing ore fluid migration to the outside,show the iron isotope zoning of time and space,illustrates the mineralization type,the ore minerals,zoning of ore-forming elements are closely related to the ore fluid evolution.