Geochemical Characteristics And Ore-bearing Analysis Of Monzonitic Granite In Diyingzi Area,Heilongjiang

The Daxinganling area where the study area is located has experienced a large number of tectonic regimes superimposed and large-scale magmatism event have taken place.In this paper,the large-scale monzonitic granites in the Diyingzi area of Heilongjiang Province are taken as the object of study.Its genetic type,tectonic setting,metallogenic structure and ore-bearing properties will be discussed throngh the study of the petrological characteristics,geochemical characteristics and zircon chronology characteristics.The main rock type of the granites in the study area are coarse to medium grained porphyritic monzonitic granite.The results of U-Pb geochronology of two groups of zircons are 180.0±1.1Ma?MSWD=0.83?and 180.6±1.1Ma?MSWD=0.19?.It turns that the diagenetic age of the granites are Early Jurassic period.The granites are high SiO₂ content,acidic rock,rich K and poor Na.A/CNK=1.02-1.06,indicating that the granites are peraluminous granites.And the granites are calcium-alkaline granite which?mostly between 2.06-2.67.The magma has a higher acidity and a stronger fractionation and evolution.The trace elements of the granites are characterized by enrichment of lithophile elements such as Rb,Ba,and Sr,and are rich in high field strength elements such as Th,U,La,and Ce.The high field strength elements Nb and Ta are relatively depleted.The total rare earth element is 101.43×10^-6-151.16×10^-6,LREE/HREE is 10.92-25.37,which shows the obvious enrichment of light rare earth elements and the depletion of heavy rare earth elements.The?Eu of the granites are 0.58-1.00,depletion of Eu,but not obvious.The geochemical characteristics of the monzonitic granites in the study area are similar to the"C"type Adakite of the incrassated basaltic lower crust.The monzonitic granites in the study area may have formed in the active continental margin environment under the subduction of the Mesozoic Mongolia-Okhotsk oceanic crust.Through the tectonic-magmatic action related to the closure of the Okhotsk Ocean,the ore-forming hydrothermal fluids migrate along the structural faults and fissures,forming more volcanic hydrothermal and medium-low temperature hydrothermal filling quartz vein type silver-gold or gold deposits.Based on the data available,the rare earth minerals of the monzonitic granites in the study area may have poor ore mineralization,and the uranium mineralization may be poor.The rare ore metals such as Be,W,Sb,Nb and Ta may have poor ore-bearing properties,not a tin mineralized granite.But there may be potential prospects for gold and copper prospecting.