Distinguishing geochemical anomalies from background is a basic task in exploratory geochemistry. The derivation of geochemical anomalies from stream sediment geochemical data and the decomposition of these anomalies ...Distinguishing geochemical anomalies from background is a basic task in exploratory geochemistry. The derivation of geochemical anomalies from stream sediment geochemical data and the decomposition of these anomalies into their component patterns were described. A set of stream sediment geochemical data was obtained for 1 880 km 2 of the Pangxidong area, which is in the southern part of the recently recognized Qinzhou-Hangzhou joint tectonic belt. This belt crosses southern China and tends to the northwest (NE) direction. The total number of collected samples was 7 236, and the concentrations of Ag, Au, Cu, As, Pb and Zn were measured for each sample. The spatial combination distribution law of geochemical elements and principal component analysis (PCA) were used to construct combination models for the identification of combinations of geochemical anomalies. Spectrum-area (S-A) fractal modeling was used to strengthen weak anomalies and separate them from the background. Composite anomaly modeling was combined with fractal filtering techniques to process and analyze the geochemical data. The raster maps of Au, Ag, Cu, As, Pb and Zn were obtained by the multifractal inverse distance weighted (MIDW) method. PCA was used to combine the Au, Ag, Cu, As, Pb, and Zn concentration values. The S-A fractal method was used to decompose the first component pattern achieved by the PCA. The results show that combination anomalies from a combination of variables coincide with the known mineralization of the study area. Although the combination anomalies cannot reflect local anomalies closely enough, high-anomaly areas indicate good sites for further exploration for unknown deposits. On this basis, anomaly and background separation from combination anomalies using fractal filtering techniques can provide guidance for later work.展开更多
Serving as a way to understand the material composition,structure,and dynamic process of the Earth's interior,deep earth exploration is driven by not only mankind's pursuit of natural mysteries but also mankin...Serving as a way to understand the material composition,structure,and dynamic process of the Earth's interior,deep earth exploration is driven by not only mankind's pursuit of natural mysteries but also mankind's basic need to obtain resources and guarantee economic and social development.The first phase of deep earth exploration of China(SinoProbe)was carried out from 2008 to 2016 and tremendous results were achieved.In 2016,the China Geological Survey launched a Deep Geological Survey Project(also referred to as the Project)to continuously explore the deep Earth.Focusing on the national energy resources strategy,the Belt and Road Initiative,and major basic issues of the geological survey,the Project was carried out in Songliao Basin(an important energy base in China)and major geological boundaries and tectonic units including Qilian Mountains-Tianshan Mountains and Qinzhou-Hangzhou juncture belt.The purpose of it is to reveal the process,structure,and forming patterns of the deep ore deposits and petroleum reservoirs,clarify the evolutionary pattern and controlling factors of Mesozoic environmental climate,and discover deep fine structures of key orogens,basins,and mountains by comprehensive geophysical exploration and scientific drilling.Great achievements have been obtained after more than three years of efforts,including a cumulative 1552 km of deep seismic reflection profiles and magnetotelluric profiles,an ultra-deep continental scientific crilling well,a scientific drilling pilot hole,and a magnetotelluric array and a portable broadband seismic array,both of which cover South China.Moreover,significant progress has been made in ultra-deep drilling technology,deep oil and gas discovery in Songliao Basin,and basic geological issues of Qilian Orogen and Qinzhou-Hangzhou juncture belt in South China,greatly accelerating the deep earth exploration in China and further consolidating China's position as a power in deep earth exploration.展开更多
基金Project(1212010071012) supported by Guangdong Pangxidong Mineral Prospect Investigation, ChinaProject(41004051) supported by the National Natural Science Foundation of ChinaProject ([2007]038-01-18) supported by Nationwide Mineral Resource Potential Evaluation Projects of Ministry of Land and Resources, China
文摘Distinguishing geochemical anomalies from background is a basic task in exploratory geochemistry. The derivation of geochemical anomalies from stream sediment geochemical data and the decomposition of these anomalies into their component patterns were described. A set of stream sediment geochemical data was obtained for 1 880 km 2 of the Pangxidong area, which is in the southern part of the recently recognized Qinzhou-Hangzhou joint tectonic belt. This belt crosses southern China and tends to the northwest (NE) direction. The total number of collected samples was 7 236, and the concentrations of Ag, Au, Cu, As, Pb and Zn were measured for each sample. The spatial combination distribution law of geochemical elements and principal component analysis (PCA) were used to construct combination models for the identification of combinations of geochemical anomalies. Spectrum-area (S-A) fractal modeling was used to strengthen weak anomalies and separate them from the background. Composite anomaly modeling was combined with fractal filtering techniques to process and analyze the geochemical data. The raster maps of Au, Ag, Cu, As, Pb and Zn were obtained by the multifractal inverse distance weighted (MIDW) method. PCA was used to combine the Au, Ag, Cu, As, Pb, and Zn concentration values. The S-A fractal method was used to decompose the first component pattern achieved by the PCA. The results show that combination anomalies from a combination of variables coincide with the known mineralization of the study area. Although the combination anomalies cannot reflect local anomalies closely enough, high-anomaly areas indicate good sites for further exploration for unknown deposits. On this basis, anomaly and background separation from combination anomalies using fractal filtering techniques can provide guidance for later work.
基金This work was co-supported by the China Geological Survey project(DD20190012,DD20190011,DD20190010,DD20160207,D20160209,DD2016008,DD20160082 and DD20189702).
文摘Serving as a way to understand the material composition,structure,and dynamic process of the Earth's interior,deep earth exploration is driven by not only mankind's pursuit of natural mysteries but also mankind's basic need to obtain resources and guarantee economic and social development.The first phase of deep earth exploration of China(SinoProbe)was carried out from 2008 to 2016 and tremendous results were achieved.In 2016,the China Geological Survey launched a Deep Geological Survey Project(also referred to as the Project)to continuously explore the deep Earth.Focusing on the national energy resources strategy,the Belt and Road Initiative,and major basic issues of the geological survey,the Project was carried out in Songliao Basin(an important energy base in China)and major geological boundaries and tectonic units including Qilian Mountains-Tianshan Mountains and Qinzhou-Hangzhou juncture belt.The purpose of it is to reveal the process,structure,and forming patterns of the deep ore deposits and petroleum reservoirs,clarify the evolutionary pattern and controlling factors of Mesozoic environmental climate,and discover deep fine structures of key orogens,basins,and mountains by comprehensive geophysical exploration and scientific drilling.Great achievements have been obtained after more than three years of efforts,including a cumulative 1552 km of deep seismic reflection profiles and magnetotelluric profiles,an ultra-deep continental scientific crilling well,a scientific drilling pilot hole,and a magnetotelluric array and a portable broadband seismic array,both of which cover South China.Moreover,significant progress has been made in ultra-deep drilling technology,deep oil and gas discovery in Songliao Basin,and basic geological issues of Qilian Orogen and Qinzhou-Hangzhou juncture belt in South China,greatly accelerating the deep earth exploration in China and further consolidating China's position as a power in deep earth exploration.
