Environment Attribute Model Of Rongna Deposit,Tibet

Rongna deposit is located in the territory of wuma township,changze county,Tibet autonomous region,and it's tectonic location is on the north of west Bangong Lake-Nujiang Metallic Belt,and on the south of Qiang Tang Bolck.At present,Rongna is the only porphyry-epithermal deposit found in Duolong ore field,porphyry mineralization superimposed on the epithermal mineralization.After the mineralization,the upper part of the ore body is covered by continental volcanic rocks.In medium-shallow part,the products of epithermal mineralization superimpose on the porphyry ore body.The deep part is mainly porphyry ore body.The deposit is currently in the exploration-scientific research and technical reserve stage before exploration.Environmental characteristics before deposit development are deposit environment attribute,the environment attribute model of rongna deposit is established by related research.The study of environment attribute model can provide basic information for the research and production work of ore deposits,filling the research gap of environment properties of ore deposits in northern Tibet.The main research results are as follows:?1?The pH value of river pollution source acidic water is around 2³,strong acid environment,heavy metal elements are high in this area.The single pollution index shows that Cr,Cd,Pb,Hg,and As pollution index were all less than 1,not exceed national?class water standard,no pollution.Cu and Zn elements exceed the national?class water standard,light pollution.Comprehensive pollution index results show that the water quality of study area is in good condition.?2?The soil quality in the study area is poor,riverbed sediment is alkaline,the section soil is from acidic to alkaline.The results of single pollution index show that the sediment pollution elements in riverbed are mainly Cu,As and Zn,the Zn element is polluted only in the upstream of the river bed,the pollution degree of Cu and As elements gradually decreases from upstream to downstream.The pollution elements in section soil are Cu and As,one sample of As element is heavily polluted,More than10.1 times national?class soil standard.The results of the comprehensive pollution index shows that the pollution level of riverbed sediment decreases gradually from upstream to downstream,the degree of section soil pollution is significantly higher than the river sediment.?3?Heavy metal elements morphological analysis shows that Zn,Cu,Cr,Pb,As and Hg elements are mainly in residue state in soil and can be stable in the soil for a long time.The Cd content of carbonate state adding ion exchange is 35.2%,having great influence on the surrounding environment,it is the main source of soil heavy metal hazard.Carbonate state adding ion exchange state adding water soluble state Zn,Cu,Cr,Pb,As and Hg of riverbed sediment are significantly higher than profile soil,showing the degree of heavy metal pollution in river bed is higher than that in profile soil.?4?Factor analysis of main trace elements of Rongna deposit 3204 drilling core shows that F1 factor represents Potassium mineralization stage,accompanied by light rare earth elements?Pr?Ce?Nd?La?Sm?Eu?.F2 represents a phase of hydrothermal activity,accompanied by heavy rare earth elements?Y?Er?Ho?Yb?Lu?Dy?Tb?Gd?.F3 represents a phase of galena alteration.F4 represents the main metallogenic stage of the Cu metal,accompanied by a large number of As,Sb,Zn and Cd mineral.F5 represents the formation stage of alkaline minerals.F6 represents metallogenic stage of Mo metal.F7 represents a phase of hydrothermal activity.F8 represents a fluid activity rich in CaO.F9 represents a fluid activity rich in Na₂O.?5?Rongna river flows from southeast to northwest into Biecuo lake.In contaminated source acid water,the average of Cr element is 5.13 mu g/L,Cu element is 683.4?g/L,Zn element is 459.4?g/L,Cd element is 0.36?g/L,Pb element is0.69?g/L,Hg element is less than 0.10?g/L,As element is less than 0.83?g/L,the average of SO₄^2-is 473.3mg/L.Acidic water stream velocity is 0.00166m³/s,the north-south fault of the deposit was formed at the time of 9Ma,the total amount of heavy metals released to the surrounding environment since the ore-forming is calculated:Cu 996000 tons,Pb 882.4 tons,Zn 661000 tons,As less than 288.7 tons,Cd 490.2 tons,Cr 1340.8 tons,Hg less than 47.1 tons,SO₄^2-349827390 tons.?6?Detailed study on petrography,mineralography and geochemistry of heavy metal elements for deposit ZK3204 core,river water,acidic water,riverbed sediment,profile soil,original rock and oxidized ore are carried out,establishing the environment attribute model of rongna deposit.