A Comparison Study Of Anomaly Delineated Method For Geochemical Exploration In North Of Chengde

Exploration geochemistry is the method of prospecting by studying of the distribution of elements in geological body, discovering abnormity, explaining and evaluating then further delineating of ore prospecting areas and prospecting target area. As one of important prospecting technology, it mainly process-geochemical data. Its purpose is to effectively and reasonably distinct geochemistry background and geochemical anomalies, find geochemical anomalies related to mineralization from big data and then cooperate comprehensive information such as geology, geological prospecting and remote sensing for finding ore.Chengde, Hebei Province is the main output areas on gold, silver, copper, lead and zinc deposits. Besides Yu,erya gold mine postmagmatic hydrothermal gold deposit, the explored deposits are mostly small and medium size deposits, there are also a number of small deposits and known ore occurrences. The study area is the northern part of Chengde, where the main mineral are silver, lead, zinc polimetallic ore, object of study is mainly the 1:20 0000 stream sediment data（Au, Ag, Pb, Zn, Mo five elements）.Firstly, the paper counts characteristic parameters of the northern part of Chengde 2798 geochemical data, and analyze the correlation of the various elements, among which is mainly the R-point cluster analysis and factor analysis. So it is concluded that relevance among Ag, Pb, Zn, Mo is better, becoming a combination while Au and other elements have a poor relevance, as a combination.Secondly, this paper respectively calculates anomaly threshold of different elements by traditional statistical methods（mean + twice standard deviations）, 85% cumulative frequency method, content- area method, and combine with the known ore occurrences to comparatively analyze founding that Au、Ag elements are better in content- area method, Pb, Zn elements are better in traditional method, and Mo element is better in cumulative method. Ultimately determined the anomaly threshold is as follows: Au: 2.2×10^-9, Ag: 101.7×10^-6, Pb: 35.8×10^-6, Zn: 101.5×10^-6, Mo: 3.1×10^-6.Finally, this paper draws integrated anomaly map by combination of elements, combining the existing data, and totally circling six ore prospects, which has an important guiding role-of prospecting work.