The Characteristic And Mineralization Of Magmatites In Dongfanghong Gold Deposit,Shanxi Province

The north platform of China is the oldest platform.In the Mesozoic especially the late Mesozoic,the lithosphere was affected by the subduction of the Pacific plate to Eurasian plate,lead to the lithospheric thinning with a large of magmatic activity;Considered with geotectonic view,Taershan mountain is at the middle part of the North China plate.In the Yanshanian,because of some intrusion of alkaline or slight alkaline complex,Taershan area have the abundant of mineral resources and the types of deposit are complex.Dongfanghong gold mine is located in the middle part of Taershan mountain,the gold orebody is related to the distribution of the rock veins and the alkaline and the slight alkaline of Yanshanian is related to the regional tectonic.This paper paper not only includes field work and micropetrography of Dongfanghong gold deposit,but also analyses the characteristic ot the petrochemistry,the vein rocks relation to gold mineralization and the geochemistry of the characteristic of the intrusive rocks,this paper also includes the electron microprobr of the gold particles.The main achievements and results obtained are as follows:(1)From the geological field work,microscopic identification and comprehensive analysis of the major element of magmatic rock,we have primary definition the syenitoid and monzonite have the characteristic of TTG combination feature,alkaline series,aluminous-metaluminous rock.The trace element enrich K,Sr and largr ion Pro stone elements,and loss Ta,Ti,P high field-strength element,the Sr/Yb value is high,there is not the negative anomaly of Eu.It shows the characteristics of arc magma.(2)The syenite and monzonite of Dongfanghong gold district derived from the lower crust partial melting,caused by the Pacfic plate subduction to Eurasian plate,and with the further of subduction,the effect of subduction transform to the horizontal compressed tectonic movements.(3)In the Dongfanghong gold deposit,the main mineral of gold ore is the independent natural gold,the microscopic and the submicroscopic level is the particle size.The Modes of occurrence of Au mainly are intergranular gold.According to the analysis of electron microprobe chemical,the percentage of Au is about 969,belongsto the series of natural gold.(4)Dongfanghong gold deposit has the same characteristics as the medium-low temperature hydrothermal gold deposit: Magmatism provide the hydrothermal mineralization,and the mineralized hydrothermal superimposed on the intrusive rock.Because of the of lithosphere and mantle interaction,the lower crust gold containing material was excitation,the magmatism provide the ore-forminghydrothermal for the gold metallogenic.Then the ore –forming hydrothermal move up the upper crust and enrichment mineralization in the suitable ectonic location,and shows more ore-finding potential in the intersection part of fracture structure In the northwest of mining area.