| Mineral resources supply is very important for the sustainable development of national economy,and the mineral resources prediction is one of the important technologies for the resources exploration.Direct mineralization information is generally serious lack in the geological covering zone,and the study of the geochemical element anomaly becomes the key point in the study on mineral exploration information.Geochemical element anomalies often reflect the mineralization enrichment information indirectly or directly.Therefore,the study of geochemical anomalies is the important content in resource prediction,such as the resource prospect area determination,classification of mineralization types.Based on the regional supergene geochemical element data,the fine evaluation of geochemical assemblage anomaly has been discussed by the comprehensive application of existing mathematical geological methods and model optimization scheme.Weak combination anomaly information has been taken from the element combination type division,and the comprehensive evaluation model has been established for the improving the accuracy and quality of geochemical composition anomaly method quantitative.Finally,the reliable geochemical anomaly information can be provided for the fine prediction of regional mineral resources.The southeast of Jilin province has been chosen as the study area,which is located in the west margin of the Yalu River metallogenic belt with intensive magmatic activity and tectonic activity.Drainage and soil are developed with intensive supergene action forming large scale vegetation coverage area.Geochemical survey is mainly based on soil survey and the distribution of the geochemical elements is special.Based on the above geological situations,a large number of shielding of element high value or inaccurate sampling values may be in the geochemical sampling,which interferes the medium and large scale of the geochemical exploration to a certain extent and affect the determination and evaluation of geochemical anomalies.Therefore,special treatment and fine evaluation of geochemical data for the study area are the main content for this paper.Based on the geochemical survey data(1:50000 scale for the Helong,1:10000 scale for the Sifangtai and 1:2000 sacle for the Xichuan in the SE Jilin province),the study work in this paper is the abnormal quantitative analysis.Different model of the geochemical composition anomaly has been established by the factor-universal Kriging method and multivariate canonical trend surface method,and the anomaly analysis of element combination in each region has been carried out.Then,the geochemical element assemblage anomaly type has been identified.The noise reduction has been carried out for the combination of anomalies by the wavelet analysis method in order to elimination of regional geo noise interference.In terms of the combined anomaly weak information,information amplification has been used by the combination matching analysis improving the combined anomaly analysis accuracy.Geological spatial specialization has been identified combined with the structural and stratigraphic lithologic characteristics for the combination anomaly.Isoline and distribution maps of regional geochemical anomaly have been compiled by the MapGIS and Surfer software.Finally,matching analysis,evaluation and interpretation have been carried out for the regional geochemical anomalies and distribution characteristics of known deposits and mineralized points.(1)In terms of the difficult points in the analysis of geochemical anomaly in vegetation coverage area,nonlinear geochemical spatial quantitative combination of different model has been established.The seeking difference method for single element has been improved in the theory and method,which greatly increased the richness and comprehensive level of geo-information and improved the location rediction accuracy of resource perspective.(2)The combination of quantitative differences and comparative analysis have been carried out for the middle and large sacle geochemical element data(1:50000,1:10000 and 1:2000)respectively.The applicability and accuracy of the spatial quantitative combination method of difference have been discussed under different scales and resolution ratio.(3)Based on the two-dimensional distribution conditions for the geochemical data,two dimensional noise reduction has been carried out for the geochemical assemblage anomaly by the wavelet analysis theory,which eliminated the system noise interference,screen out the partial false anomaly and improve the combination anomaly accuracy.(4)Based on the linear and nonlinear difference of geochemical quantitative combination model,combined abnormal weak signal in the region has been enlarged by the combined matching analysis method.Then,the tentative method for improving the precision and quality of the geochemical composition anomaly has been given under unbalance or lack of geological information.(5)In terms of the geochemical anomaly analysis of stream sediments,long axis vector composition rule of combined anomaly contour has been carried out for the tracing analysis,and the source of the combined anomaly has been discussed coupled with distribution features of the surface catchment basin.Vegetation cover geochemistry,Quantitative spatial composition anomaly,wavelet denoising,combined weak anomaly amplification and combination match analysis. |
PDF Full Text Request