Regional Geochemical Characteristics Of Jin Da Monoblock Exploration Area In Tibet

Jin Da monoblock exploration area situated on Central and East the Tethys-Himalayan orogenic belt,in which there found a number of large lead-zinc mineral deposits in the last decade,where has become the important lead-zinc ore concentration area in Tibet.But to the lack of understanding of regional geochemical characteristics and the viewpoint is not unified.Based on collection and management of the regional geological data,the predecessor research results,the latest exploration achievements and 1:500000 stream sediment survey,to filtrate,analyze and summarize the collection data of main ore-forming element and classic companion elements.The methods of probability distribution whether to fit the normal distribution;The methods of element abundances coefficient,variation coefficient and skewness to analyze element data structure;The methods of R-type clustering analysis and factor analysis to identify prospecting indicator composite-elements:(1)Ag-Cu-Pb-Zn,(2)W-Sn-Mo-Bi.The abnormal iteration methods to caculate 8elements of regional background value and anomaly threshold,and according this data to divided into three-level concentration zoning of the traditional geochemical and catchment basins geochemical,to superposed mine figure to contrast analysis of the both methods.The authors suggest that the traditional geochemical anomalies are larger in size,and have concentration zoning,concentration centers,but small band,irregular shape,and general trend in NW-SE direction.The catchment basin are smaller in size but overlap known mineralization points,and have concentration zoning,concentration centers with outstanding phenomenon,irregular shape,and general trend in NW-SE direction.Compared with previous methods,the later give a better indicator,imprint the information of known mineralization points reasonably,abnormal express moreintuitive and clear,with smaller anomaly area.The methods of catchment basin have been more conductive to the further prospecting and more suitable for geochemical anomalies prospecting.Further to outline the mineral prospecting area: six silver-based and five molybdenum-based catchment basin geochemical metallogenic prospect areas.