The Identification And Evaluation Of Regional Geochemical Anomaly In Lhasa-Zetang Area

In recent years, along with the1:200000regional geochemical Exploration workcarried out, we have accumulated a lot of information, while how to use the obtaininformation in an scientific and efficient way is directly related to the results of regionalgeochemical work and economic benefits. The study area is located in Central Tibet,tectonic includes Lhasa-Chayu partition, Lazi-Qusong partition, the partition of theKangma-Longzi and North Himalayan, High Himalayan zone. The Yarlung Zangbofracture as the representative, the region developments a large number of faults, thegeological background also complexity, therefore, how to use the existing geochemicaldata in a scientific way to filter out abnormal geochemical from the complexbackground is the key.On the basis of analyse the regional geological metallogenic background, theauthor studys and evaluates the geochemical exploration data distributioncharacteristics、 the divide of the geochemical background and abnormal、 theextraction and filtering of geochemical anomaly information and the mineralizationpotential of the abnormal.After text the data we found that some important elements of the stream sedimentof the regionalization exploration do not follow a normal distribution or lognormaldistribution. The stream sediment contact with geological units of underlying bedrockclosely which have different values of geochemical background.Use the Exploration data processing (EDA method) to statistics the outlies of(lower limit of abnormal)each geological unit or sub-district. Utilize the “subintervalarea anomaly threshold contrast filtering method” and the “Geochemical explorationweak information extraction method” to processing the raw data of the1:200,000stream sediment data, Preliminary delineation the single element anomalies and themulti-element composite abnormal.According to the abnormal combination of elements、the center of the abnormalconcentration etc, with the distribution of various types of proven industrial deposits,author screens26comprehensive exception,16exception of Class A,10abnormalof Class B in the study area. The author sorts the anomalous zone based on thepossibility of mineralization, as the order for the work of verify abnormal.