As direct prospecting data,geochemical data play an important role in modelling prospect potential.Geochemical element assemblage anomalies are usually reflected by the correlation between elements.Correlation coeffic...As direct prospecting data,geochemical data play an important role in modelling prospect potential.Geochemical element assemblage anomalies are usually reflected by the correlation between elements.Correlation coefficients are computed from the values of two elements,which reflect only the correlation at a global level.Thus,the spatial details of the correlation structure are ignored.In fact,an element combination anomaly often exists in geological backgrounds,such as on a fault zone or within a lithological unit.This anomaly may cause some combination of anomalies that are submerged inside the overall area and thus cannot be effectively extracted.To address this problem,we propose a local correlation coefficient based on spatial neighbourhoods to reflect the global distribution of elements.In this method,the sampling area is first divided into a set of uniform grid cells.A moving window with a size of 3×3 is defined with an integer of 3 to represent the sampling unit.The local correlation in each unit is expressed by the Pearson correlation coefficient.The whole area is scanned by the moving window,which produces a correlation coefficient matrix,and the result is portrayed with a thermal diagram.The local correlation approach was tested on two selected geochemical soil survey sites in Xiao Mountain,Henan Province.The results show that the areas of high correlation are mainly distributed in the fault zone or the known mineral spots.Therefore,the local correlation method is effective in extracting geochemical element combination anomalies.展开更多
Observations made in different superlarge\|large gold deposits in Ailaoshan gold metallogenic belts, Yunnan Province, China, on the eastern margin of the Qingzang (Himalayas—Karakoram—Tibet) were investigated. Geote...Observations made in different superlarge\|large gold deposits in Ailaoshan gold metallogenic belts, Yunnan Province, China, on the eastern margin of the Qingzang (Himalayas—Karakoram—Tibet) were investigated. Geotectonically, the study area is situated in the conjoint between the Tethys and Himalayas tectonic domain, characterized by very complex geological structure, with strongly influenced by the Himalayas in late development.1\ Regional geology and gold deposits\;Ailaoshan gold metallogenic belts is localized between Ailaoshan super lithospheric faults and Jiujia—Anding brittle\|ductile shear zone, with NNW\|trending about 250km long. To southward, Zhenyuan supergiant gold deposits, Mojiang large gold deposits, and Daping giant gold deposits hosted in low metamorphic volcanic\|sedimentary rocks (D—C). Ore types include gold\|bearing quartz veins, gold\|bearing altered rocks, and the mixing of the two types. Most of gold orebodies took their positions in the substructures of the brittle\|ductile shear zone.展开更多
基金supported by the National Natural Science Foundation of China(Nos.41272359,210100069)。
文摘As direct prospecting data,geochemical data play an important role in modelling prospect potential.Geochemical element assemblage anomalies are usually reflected by the correlation between elements.Correlation coefficients are computed from the values of two elements,which reflect only the correlation at a global level.Thus,the spatial details of the correlation structure are ignored.In fact,an element combination anomaly often exists in geological backgrounds,such as on a fault zone or within a lithological unit.This anomaly may cause some combination of anomalies that are submerged inside the overall area and thus cannot be effectively extracted.To address this problem,we propose a local correlation coefficient based on spatial neighbourhoods to reflect the global distribution of elements.In this method,the sampling area is first divided into a set of uniform grid cells.A moving window with a size of 3×3 is defined with an integer of 3 to represent the sampling unit.The local correlation in each unit is expressed by the Pearson correlation coefficient.The whole area is scanned by the moving window,which produces a correlation coefficient matrix,and the result is portrayed with a thermal diagram.The local correlation approach was tested on two selected geochemical soil survey sites in Xiao Mountain,Henan Province.The results show that the areas of high correlation are mainly distributed in the fault zone or the known mineral spots.Therefore,the local correlation method is effective in extracting geochemical element combination anomalies.
文摘Observations made in different superlarge\|large gold deposits in Ailaoshan gold metallogenic belts, Yunnan Province, China, on the eastern margin of the Qingzang (Himalayas—Karakoram—Tibet) were investigated. Geotectonically, the study area is situated in the conjoint between the Tethys and Himalayas tectonic domain, characterized by very complex geological structure, with strongly influenced by the Himalayas in late development.1\ Regional geology and gold deposits\;Ailaoshan gold metallogenic belts is localized between Ailaoshan super lithospheric faults and Jiujia—Anding brittle\|ductile shear zone, with NNW\|trending about 250km long. To southward, Zhenyuan supergiant gold deposits, Mojiang large gold deposits, and Daping giant gold deposits hosted in low metamorphic volcanic\|sedimentary rocks (D—C). Ore types include gold\|bearing quartz veins, gold\|bearing altered rocks, and the mixing of the two types. Most of gold orebodies took their positions in the substructures of the brittle\|ductile shear zone.
