Studies On Au-polymetallic Deposit Prognosis In Baishan Area

Baishan area of Jilin Province has been designated as a city in transition resources, which is located in the eastern section of north China platform, forming an important part of the northern margin metallogenic belt of the plate. Although the ore-forming geological conditions of superiority in Baishan area, most of which are in the coverage area, it has been discovered fewer large-scale minerals , and there have been 40 types of metal deposits which are small, medium and large scale and complex-forming type. Therefore, it is a very difficult area of geological prospecting. However, with increasing difficulty of geological prospecting, the dozens of metel mines in 1950s and 1960s had been largely discontinued due to resource depletion. New resources are urgently needed to maintain economic development and social stability . In this case, enhance the gold metallogenic prognosis, studying geological background of mineralization, ore-controlling geological factors, and mineralization information are particularly important and urgent. It can provid future exploration direction for the near further prospecting.Baishan region is imbalance in the level of geological research, Laoling region has higher degree of research in geological work ,but in the Changbai basalt area has the low level of research,and this is the major problem in geological prospecting of the area based on the collected the past 1:200,000 geophysics, geochemistry and other geological information in Baishan area, the paper focused on aeromagnetic and stream sediment data and other information on the latest methods of computer processing and integrated interpretation, developed a comprehensive information metallogenetic 1:20,000 scale forecast map of the district,and got the prediction of target delineation.The particular importance work is through the aeromagnetic data processing and interpretation, the author explained the identification of the entire Baishan region, especially the coverage area of basalt rock characteristics of the spatial distribution , structural framework and the regional characteristics of magmatic activity. Based on the logical study of the geological variables, the variables principle of the extraction , reasonable assignment and the spatial relationship were made some useful attempts and given the model of quantitative and positioning prediction g. The paper's work and achievements are summarized as follows:1. Geological data interpretation: based on geological research we can find that the region is exposed well in stratigraphy. Proterozic and Cenozoic basalts are much wider than others. Tectonic setting is mainly the eastern strike of the northern margin of the North China platform. Faults have the direction of NW, NE and NS ,specially the NW and NE to more development. In the regional tectonic movements happened with the magma multi-phase activities, relevant to the movement of Fuping and Wutai plutonic, the formation of the Mesozoic Indo-Chinese-Yanshanian movement in the acidic intrusive complex formation.2. Geophysical and geochemical data interpretation: in this study we collected the 1:200,000 aeromagnetic data and stream sediment survey data to interprete deeper geophysical and geochemical information on the structural framework, magmatic rocks inferred.Aeromagnetic data processing method is upward(20km, 10km, 5km, 2.5km) extension ,the direction of a different order derivation calculation and second derivation vertical calculation. Interpreted the aeromagnetic data from the magenetic point of view of the study area gold mineralization geological conditions, inferred from such phenomena as the structure, strata, intrusive rocks, extracted the aeromagnetic data information of the strata, intrusive rocks, structure from the interpreatation of the data ,inferred structure framework of the study through different heights relevance information ,inferred the typical formation ,instrusive complex 3D,which found a number of faults to the NW. Late this group faults is later than the North East structure ,and break the integtity of the North East stucture's.The North West tectonic controls the multi-metal ore deposit. Delineation of the location of buried rock, in particular, are found in the east-west basement control of the distribution of the basalt cap.The author use Krieger method, F-Krieger method and SPSS methods to study the hydrographic sediment of geochemical data. Geochemical anomalies are identified by the method of factors - universal kriging, and using this method to implement the spatial quantitative association anomaly of element. Obtains in the area after the explanation the Au coefficient of variation to be bigger than 1.4, has the changeability .The Au changes in the region is strong and show mineralization enrichment .47 gold abnormal regions had been circled , and their distribution have the characteristics of groups. Anomalies can be divided into the town of Banshi–Liudaogou and the town of Naerhong–Shengli . Abnormal distribution of Au distribute the edge of part of the substratum and the contaction zone of rock body. From the abnormal distribution of Au can be seen that NW tectonics control Au deposit .Au, Co, Ni element anomaly superimposed with high-value effects. Co, Ni is superior to Au, Co and Au in goodess of fit, Ni. It can be concluded that Co, Ni in the ore-forming process has the same genesis, but probably for different Au mineralization or ore-forming stage. Cu, Pb, Zn element has the effect of high-value stack. Cu anomalies centers are mainly in the rock mass for the inner zone, Pb, Zn for the outer, especially the rock art.Make use of factor - F-Krieger method to study the area of 1:200,000 geochemical data, space quantitative combination of abnormal and three-dimensional DEM model were established. The results showed that abnormal portfolio is divided into three zones:ⅠDistrict is located in the southeast, Mayi town of Linjian to Lishu town of Changbai, its exposed stratigraphy is basalt. Elements combination is Co-Mn-Ti, it revealed that under the basalt cover is great potential for finding Co ore.ⅡDistrict is located in the southwest, Sandaocha town to Huaqi town of Linjian city. Elements combination is As-Au-Sb, it revealed that the band is the gold-intensive area.ⅢDistrict is in the central of study area , Wangou-Naozhi-Songshu town. Elements combination is Cr-Ni. The band revealed that this abnormal band is a process of elements aggregation which is correct with ultrabasic rocks, mafic volcanic rock.3. On the basis of study of the regional metallogenic regularity and the typical deposit, we summed up prospecting criteria in geology, geochemistry, geophysics. Gold ore-forming conditions mainly in Baishan are follows: Tectonic setting is mainly the eastern part of the northern margin of the North China plate. The magmatite condition is the formation of the Mesozoic Indo-Chinese-Yanshanian movement in the acidic intrusive complex formation. NW direction of regional fracture structure is the major structure factor controlling the regional geologic bodies'distribution, it has long-period activity characteristic. Fossil-rich strata is Zhenzhumen marble rocks of Laoling Group with thin-layer thick dolomitic marble contact zone as well as the Dalizi Formation carbon sericite phyllite, silk cloud carbon sericite phyllite thin folder marble. The Earth gravity field area shows low in the southeast and high in the northwest. Regional geochemical charactetistic mainly are Au,Co,Ni,Cu,Pb and Zn having high background numerical value, having visible concentration core and folding the high value reciprocally.Analyzed by the metallogenic geological condition, it is considered that Gold and its'polymetallic deposit correlating with deep-geophysical information which is reflected by gravitational and aeromagnetic materials, the geochemical abnormality information also openes out that resource potentiality is optimistic.4. According to the theory of synthetic information mineralization prediction, the dissertation has made the large-scale gold mining prediction and evaluation in the study area. According to the prospecting model statistical units was delineated in the study area. It's delineated 48 statistical units totally, which has predicted 37 units and known 11 units. Prediction units has been evaluated through method of the cluster analysis, the number ofⅣand logical theory of information for the study area on the statistical units, study on favorable metallogenic, positioning prediction of mineral resources, quantitative prediction and estimates of resources. No. 32, 39, 43 are pointed out that the prediction for the most important long-term gold mine area; 8, 9, 17, 22, 26, 30, 31, 46 units have some prospect, you can work as a follow-up prospecting focus units; compared with the previous two units,4, 5, 14, 15, 16, 27, 34, 37 units are forming a favorable low, as long-term reserve prospecting units. This can be provided a scientific basis for the next phase of exploration in Baishan region.