The Nanyuan Formation contains information related to the Mesozoic tectonic transformation.In this study,three representative profiles were surveyed from the Nanyuan Formation,and multiple analyses were conducted.Zirc...The Nanyuan Formation contains information related to the Mesozoic tectonic transformation.In this study,three representative profiles were surveyed from the Nanyuan Formation,and multiple analyses were conducted.Zircon U-Pb dating yielded their ages as approximately 158–146 Ma.The volcanic rocks are enriched in Rb,Th,U,K,and Pb and depleted in Nb,Ta,P,and Ti,implying their affinity for I-type granites.TheεNd(t)values(-8.3 to-6.0),^(87)Sr/^(86)Sr)i values(0.7077–0.7094)of the volcanic rock,andεHf(t)values(-8.71 to 0.12)of the Mesozoic zircons suggest that the Nanyuan Formation magma originated in the lower crust with the involvement of depleted mantle materials.The parent rocks of the rhyolitic and dacitic volcanic rocks formed by partial melting of basement rocks in South China and the andesitic volcanic rocks were derived from partial melting of the metasomatites generated by slab-mantle interaction.The fractional crystallization also played an important role in later stage.Discrimination diagrams of the volcanic rocks indicated that they formed in a volcanic arc environment.Combined with previous data,the Nanyuan Formation recorded subduction of the Paleo-Pacific Plate before regional tectonic transformation.The compressive stress field endured until the end of the Late Jurassic.展开更多
Mapping mineral prospectivity in vegetated areas is a challenge. For this reason, we aimed to map spatial distribution characteristics of linear structures detected in remote sensing images using fractal and multifrac...Mapping mineral prospectivity in vegetated areas is a challenge. For this reason, we aimed to map spatial distribution characteristics of linear structures detected in remote sensing images using fractal and multifractal models. The selected study area was the Pinghe District of the Fujian Province（China）, located in the Shanghang-Yunxiao polymetallic and alunite ore belt（within the Wuyishan polymetallic belt）, where mineral resources such as copper, molybdenum, gold, silver, iron, lead, zinc, alunite and pyrophyllite have been discovered. The results of our study showed that：（1） the values of fractal dimension for all lineaments, NW-trending lineaments, and NE-trending lineaments, are 1.36, 1.32, and 1.23, respectively, indicating that these lineaments are statistically self-similar;（2） the fractal dimensions of the spatial distribution of the linear structures in the four selected hydrothermal-type ore deposits of the Pinghe District, named Zhongteng, Panchi, Xiaofanshan and Fanshan, are 1.43, 1.52, 1.37 and 1.37, respectively, which are higher than the mean value in South China;（3） the spatial distribution of the linear structures extracted from the remote sensing image and displayed by the contour map of fractal dimensions, correlates well with the known hydrothermal ore deposits; and（4） the results of the anomaly map decomposed by the spectrum-area（S-A） multifractal model is much better than the original fractal dimension contour map, which showed most of the known hydrothermal-type deposits occur in the high anomalous area. It is suggested that a high step tendency possibly matches with the boundary of the volcanic edifice and the deep fault controlling the development of the rock mass and the volcanic edifice. The complexity of the spatial distribution of mapped lineations（faults） in the Pinghe District, characterized by high values in the anomaly map, may be associated with the hydrothermal polymetallic ore mineralization in the study area.展开更多
基金supported by the Deep Resources Exploration and Mining Project(Grant No.2019YFC0605202)China Geological Survey Project(Grant Nos.DD20221684,DD20221795,DD20201173)。
文摘The Nanyuan Formation contains information related to the Mesozoic tectonic transformation.In this study,three representative profiles were surveyed from the Nanyuan Formation,and multiple analyses were conducted.Zircon U-Pb dating yielded their ages as approximately 158–146 Ma.The volcanic rocks are enriched in Rb,Th,U,K,and Pb and depleted in Nb,Ta,P,and Ti,implying their affinity for I-type granites.TheεNd(t)values(-8.3 to-6.0),^(87)Sr/^(86)Sr)i values(0.7077–0.7094)of the volcanic rock,andεHf(t)values(-8.71 to 0.12)of the Mesozoic zircons suggest that the Nanyuan Formation magma originated in the lower crust with the involvement of depleted mantle materials.The parent rocks of the rhyolitic and dacitic volcanic rocks formed by partial melting of basement rocks in South China and the andesitic volcanic rocks were derived from partial melting of the metasomatites generated by slab-mantle interaction.The fractional crystallization also played an important role in later stage.Discrimination diagrams of the volcanic rocks indicated that they formed in a volcanic arc environment.Combined with previous data,the Nanyuan Formation recorded subduction of the Paleo-Pacific Plate before regional tectonic transformation.The compressive stress field endured until the end of the Late Jurassic.
基金supported by the“Quantitative Models for Prediction of Strategic Mineral Resources in China”(No.201211022)by the Ministry of Land and Resources of China and“Integrated Prediction Theory for Mineral Resource in Desert and Grassland Covered Areas and Geoinformation Extraction of Buried Mineral Resource”(No.41430320)by the National Natural Science Foundation of China
文摘Mapping mineral prospectivity in vegetated areas is a challenge. For this reason, we aimed to map spatial distribution characteristics of linear structures detected in remote sensing images using fractal and multifractal models. The selected study area was the Pinghe District of the Fujian Province（China）, located in the Shanghang-Yunxiao polymetallic and alunite ore belt（within the Wuyishan polymetallic belt）, where mineral resources such as copper, molybdenum, gold, silver, iron, lead, zinc, alunite and pyrophyllite have been discovered. The results of our study showed that：（1） the values of fractal dimension for all lineaments, NW-trending lineaments, and NE-trending lineaments, are 1.36, 1.32, and 1.23, respectively, indicating that these lineaments are statistically self-similar;（2） the fractal dimensions of the spatial distribution of the linear structures in the four selected hydrothermal-type ore deposits of the Pinghe District, named Zhongteng, Panchi, Xiaofanshan and Fanshan, are 1.43, 1.52, 1.37 and 1.37, respectively, which are higher than the mean value in South China;（3） the spatial distribution of the linear structures extracted from the remote sensing image and displayed by the contour map of fractal dimensions, correlates well with the known hydrothermal ore deposits; and（4） the results of the anomaly map decomposed by the spectrum-area（S-A） multifractal model is much better than the original fractal dimension contour map, which showed most of the known hydrothermal-type deposits occur in the high anomalous area. It is suggested that a high step tendency possibly matches with the boundary of the volcanic edifice and the deep fault controlling the development of the rock mass and the volcanic edifice. The complexity of the spatial distribution of mapped lineations（faults） in the Pinghe District, characterized by high values in the anomaly map, may be associated with the hydrothermal polymetallic ore mineralization in the study area.
