Deposit Geology And Metallogenic Prediction Of The Xiangkashan Mine In Luobusa Chromite Deposit,Tibet

The chromite deposit of Luobusa,currently the largest chromite deposit in China and the typically podiform chromites,is produced in Yarlung Zangbo ophiolite.According to the space distribution characteristics of the deposit,it can be divided into three mines from west to east,Luobusa,Xiangkashan and Kangjinla;chromitites have always been one of the strategtic shortage of resources,and the chromite deposit is mostly produced in the form of podiform chromite in china with large transformation and poor regularity of the ore body,which of cource enhances the difficulty of prospecting.Xiangkashan mine,as one of the most potential in the Luobusha chromite deposit,the distribution of deep ore bodies and potential for prospecting are also key issues to be solved.In this paper,through detailed geological research of deposits and based on the existing drilling data,a three-dimensional visual geological model and borehole element anomalies are constructed,minerogenetic regularity and prospecting indicators are further summarized so as to carry out the minerogenetic prediction.By establishing the geological and three-dimensional visualization models of the deposit,the spatial distribution of the ore body in the study area is found to be obviously controlled by the Luobusa rock mass and structure,mainly by “distributed along the band,appeared in groups and concentrated in sections” and “the ore body types in plane are like echelon structure,and the section are in the shape of imbrication.The ore bodies are in the same direction as the rock mass,and tends to the south.The ore body shapes mainly include podiform,veins,lens and sacs.The structures of ores mainly are massive,disseminated,banded,pisolitic,and the textures of ores mainly contain euhedral,subhedral and relict.The host rocks consists of mantle harzburgite and dunite,with different degrees of serpentine and carbonates.The contacts between the ore body and the surrounding rocks are sometimes sharp,and sometimes gradually changing,And most of the orebodies are hosted in harzburgite belt with dunite.By analysing geochemical anomalies of borehole elements,we find that the content of Zn?Mn?Cr?Ni?V?Al?Fe?K and Ti increased in the vicinity of the ore body,while the content of other elements did not change significantly with the increase of depth.,In view of the correspondence between elements and ore bodies,We chose Zn,Mn,Cr,V,Al,Fe,K,Ti elements to establish a geochemical anomaly map of the borehole profile,and found that these elements have obvious anomalies near the ore body and have good indication significance.which has a good indication value.Thus,the anomaly range of Cr,Mn,Al,Zn,V,Fe,K and Ti elements can be used to roughly define the ore body.According to the existing drilling data,the depth of the ore in the northern ore belt of Xiangkashan is concentrated between 50-125 m,and the depth of the southern ore belt is concentrated between 275-375 m.Based on the deposit geology,the establishment of three-dimensional model,the analyzation of borehole element anomalies and the combination of geophysical and remote sensing information,we believe that the south of XII-XIV and VIII groups in Xiangkashan have large prospecting potential.