Geological Features Of The Taoge Rock Mass,Lalingzaohuo,East Kunlun Orogenic Belt,NW China And Its Related To Mineralization

The mineralization around the Taoge rock mass,Lalingzaohuo,East Kunlun Orogenic Belt,NW China is rich and remarkable,However,the ore invasion remains unknown.In this paper,the Taoge rock mass is taken as the starting point of the study,and a detailed study is made of the Taoge rock mass and mineralization around the rock mass.The geological characteristics and its relationship with mineralization are obtained,and it is inferred that the rock mass is one of the possible ore intrusions in the Zhongyou region.Geological mapping is carried out on the Taoge rock mass and its surrounding rocks.It is found that the rock mass is in intrusive contact with gneiss.The occurrence of gneiss shows that it is roughly an anticline with rock mass as its hinge.It shows that the Taoge rock mass is in accordance with the requirements of ore intrusion.The Taoge rock mass itself is auriferous,enrichedcopper;this indicates that the source of ore-forming material conforms to the requirement of ore intrusion.A detailed mineralogical study of the Taoge rock mass is carried out.Electron microprobe analysis of metallic minerals shows that the gold bearing minerals are pyrite and magnetite.Cathodoluminescence studies indicate that plagioclase is commonly present in accretion margins.The grade of plagioclase was determined by double crystal method with sodium acetate,and the grades of plagioclase were classified into two groups.The composition of plagioclase has been analyzed by electron probe.It is found that plagioclase is divided into two types: basic plagioclase and neutral plagioclase.These indicate that the rock has undergone two different crystallization processes.Two fluid activities can be identified by the CSD curve pattern and the SiO2 and amphibole content.The preferred orientation of amphibole shows that the directional strength of the intermediate sample is greater than the directional strength of the edge sample;this shows that the intensity of the second fluid activity is greater than that of the first fluid activity.A geochemical analysis of the Taoge rock mass has been carried out.The content of SiO2,Na2 O,Fe2O3,P2O5 and K2 O increased during the cooling crystallization process of the Taoge rock mass,while the contents of Al2O3,Ti O2 and CaO decreased in general.The REE contents in the Taoge rock mass are obvious heavy REE earth losses and negative Eu anomalies,Show that the rock has undergone severe alteration.The negative anomalies of Nb and Ta indicate that the Taoge rock mass should be volcanic rocks of island arc,this coincides with the tectonic setting of the island arc collision in the Middle Triassic period of the period.The time of formation of rock mass is 225~230Ma,while the time of formation of activated magma in the lower part of rock mass is 245~250Ma.There are two zones in crystalline temperature of rock mass:493 ~650? and 752 ~810?;The pressure ranged from 2.81 Kbar to 1.54 Kbar.The average temperature of the lower temperature samples is 2.68 Kbar,The average pressure of the six higher temperature samples is 2.15 Kbar.It shows that the rock in different parts of rock undergoes a crystallization process with different temperature and pressure.The formation of theTaoge rock mass is--The first fluid activity--Crystallization coarsening of rock mass--Second fluid activity--Crystallization coarsening of rock mass;this is a crystallization process of fluctuation.Moreover,the intensity of the second fluid activity is greater than that of the first fluid,the activation of lower magma during fluid activity,Lead to zircons from lower magma chambers.