| The study area is in the Gangdese metallogenic belt,which is a very important metallogenic belt of the Qinghai-Tibet plateau.In this paper,the study area from measures frequently county in southern Tibet ali region.Since the research area belongs to alpine region,whose natural climate condition is very bad,and the traffic of the study area is not convenient.Predecessors in the geochemical prospecting work is given priority to small scale like with 1:500,000.And the purpose of this article is based on the large scale geochemical prospecting like 1:50000 river sediments,which is the first time in the study area.Paper combined with the geological background in the study area,the Ag,As,Au,Bi,Cu,Fe,Hg,Mn,Mo,Pb,Sb,Se,Zn,Cd,Sn,W,Cr,Co,Ni ect 19 kinds of elements in ore-forming analysis,and mainly solve the following problems:(1)the determination of background value and anomaly threshold;(2)The identification and extraction of geochemistry under the background of complex geological settings;(3)The relationship between regional geochemical anomaly and element anomalies in the study area;(4)The analysis of elements anomaly'cause and the appraisement of elements anomaly;(5)The delimited of association anomalies and the division of prospecting area.The research area is located in the lung-textile composite jomda arc belt and ladakh-south mountain,the contact area of magmatic arc of every corner,the regional tectonic deformation is relatively strong.The emplacement of intrusive rocks in late Yanshanian and Himalayan was respectively early two cycle.The direction of Magmatic rocks showed a north-south east to west orientation in the study area,in compliance with regional tectonic belt.Through the data analysis of stream sediments in the study area,The centre of element anomaly mainly concentrated in magmatic rocks near region and its development,which shows that the study area's element anomaly were strictly controlled by magmatic hydrothermal activity,and the invasion of magmatic hydrothermal provides material source and heat source conditions for anomalous elements in the study area.Through the analysis of the spatial distribution of elements in the study area anomaly characteristics and the correlation between each element,We found the W-Sn-Mo-Bi composite anomaly with the close relationship to intermediate-acid rock mass and the Ag-Pb-Zn-Cd composite anomaly related to magmatic hydrothermal activities in the area by analysing the spatial distribution feature of element in the study area and the correlation of these elements.According to the views that the background value has few connections with mineralization of the predecessors,we can believe that there should be great potential to mineralize independently with the reason that the geometric average of Au-Cu is lower than both the alpine mountain and the nationwide watery sediment,and the concentration gradient of Au and Cu changes greatly in the area.The intensity of As and Sb element abnormal concentration's centre is higher,which is affected by the surface drainage handling effect.the trend of the anomalies are along the stream flow distribution,the spatial distribution characteristics of anomaly shows its certain prospecting potential or of the ore-formin of Ag,Pb,Zn and other multi metal elements.Finally,by all the consideration of element anomaly combination,the correlation between each element,the symbiotic and association characteristics and the spatial relationship of anomalies and geological background,the area was divided into four prospecting area.Among them,the class B-1 prospecting area is located in the northwest of study area,which more likely possesses a ore-forming potential of Cu element;Class B-2 prospecting area is located in the middle of the study area,which more likely possesses a ore-forming potential of Cu-Au-Mo,W-Sn etc combination elements;Class C-1 prospecting area,which more likely possesses a independent ore-forming potential of Au element;Class C-2 prospecting area is located in the southeast of study area,which shows a ore-forming potential of Ag-Pb-Zn combination element. |
PDF Full Text Request