In this paper,25 new terrestrial heat flow values newly observed along the mid-segment of the Tancheng-Lujiang fault zone are listed.With these geothermal data and 37 other terrestrial heat flow values(previously publ...In this paper,25 new terrestrial heat flow values newly observed along the mid-segment of the Tancheng-Lujiang fault zone are listed.With these geothermal data and 37 other terrestrial heat flow values(previously published),we describe the distribution features of terrestrial heat flows in the area.In this research,the two-dimensional temperature structure from the surface to lithospheric bottom of the Huaibei-Sixian-Jinhu profile is inferred by using the finite-element method and the temperature and heat flow of sedimentary,granitic,and basaltic layers is calculated.展开更多
A comprehensive discussion on the deep seated genesis of gold metallogenic materials and the tectono magmatic controls over gold deposits is given in this paper, which is based on the crustal and upper mantle struct...A comprehensive discussion on the deep seated genesis of gold metallogenic materials and the tectono magmatic controls over gold deposits is given in this paper, which is based on the crustal and upper mantle structural characteristics of the Jiaodong massif, the property, activation history and styles of the Tancheng Lujiang fault zone, as well as a series of accompanying tectono magmatic events. Prediction for further prospecting gold deposits in the area is also made.展开更多
The great Tancheng earthquake of M81/2 occurred in 1668 was the largest seismic event ever recorded in history in eastern China. This study determines the fault geometry of this earthquake by inverting seismological ...The great Tancheng earthquake of M81/2 occurred in 1668 was the largest seismic event ever recorded in history in eastern China. This study determines the fault geometry of this earthquake by inverting seismological data of present-day moderate-small earthquakes in the focal area. We relocated those earthquakes with the double-difference method and found focal mechanism solutions using gird test method. The inversion results are as follows： the strike is 21.6°, the dip angle is 89.5°, the slip angle is 170°, the fault length is about 160 km, the lower-boundary depth is about 32 km and the buried depth of upper boundary is about 4 km. This shows that the seismic fault is a NNE-trending upright right-lateral strike-slip fault and has cut through the crust. Moreover, the surface seismic fault, intensity distribution of the earthquake, earthquake-depth distribution and seismic-wave velocity profile in the focal area all verified our study result.展开更多
The Tan-Lu fault zone is a large NNE-trending fault zone in eastern China.Investigations of the structures of the fault zone and its surrounding areas have attracted much attention.In this study,we used dense-array am...The Tan-Lu fault zone is a large NNE-trending fault zone in eastern China.Investigations of the structures of the fault zone and its surrounding areas have attracted much attention.In this study,we used dense-array ambient noise tomography to construct a threedimensional shear wave velocity model of shallow crust in an area about 80km×70km in Lujiang,Anhui Province,eastern China.For approximately one month we collected continuous ambient noise signals recorded by 90 short-period seismographs in the region,and obtained the short-period Rayleigh wave empirical Green's functions between stations by the cross-correlation method;we also extracted 0.5–8 s fundamental mode Rayleigh wave group velocity and phase velocity dispersion curves.Based on the direct surface wave tomography method,we jointly inverted the group velocity and phase velocity dispersion data of all paths and obtained the 3-D shear wave velocity structure in the depth range of 0–5 km.The results revealed important geological structural features of the study area.In the north region,the sedimentary center of the Hefei Basin—the southwestern part of the Chaohu Lake—shows a significant low-velocity anomaly to a depth of at least 5 km.The southwestern and southeastern regions of the array are the eastern margin of the Dabie orogenic belt and the intrusion area of Luzong volcanic rocks,respectively,and both show obvious high-speed anomalies;the sedimentary area within the Tan-Lu fault zone(about 10 km wide)shows low-velocity anomalies.However,the volcanic rock intrusion area in the fault zone is shown as high velocity.Our shallow crustal imaging results reflect the characteristics of different structures in the study area,especially the high-speed intrusive rocks in the Tan-Lu fault zone,which were probably partially derived from the magmatic activity of Luzong volcanic basin.From the Late Cretaceous to Early Tertiary,the Tan-Lu fault zone was in a period of extensional activity;the special stress environment and the fractured fault zone morphology provided conditions for magma in the Luzong volcanic basin to intrude into the Tan-Lu fault zone in the west.Our 3-D model can also provide important information for deep resource exploration and earthquake strong ground motion simulation.展开更多
Four samples of plagioclase and biotite from the Shaxi porphyry in the lower part of the Yangtze metallogenic belt were analyzed for age determination with the ^40 Ar/^39Ar method. The results yield reproducible ages ...Four samples of plagioclase and biotite from the Shaxi porphyry in the lower part of the Yangtze metallogenic belt were analyzed for age determination with the ^40 Ar/^39Ar method. The results yield reproducible ages of 126 Ma to 135 Ma with a high level of confidence according to the agreement between isochron and plateau ages. The four Ar-Ar ages are relatively consistent within the analytical error. These ages are also consistent with, but more precise than, previous K-Ar and Rb-Sr ages and thus provide better constraints on the time of porphyry formation and associated Cu-Au mineralization along the middle to lower part of the Yangtze metallogenic belt. The ages of 126 to 135 Ma are interpreted to represent the intrusive time of the Shaxi porphyry, so that the Cu-Au mineralization should have occurred later due to the post-magmatic hydrothermal event.展开更多
文摘In this paper,25 new terrestrial heat flow values newly observed along the mid-segment of the Tancheng-Lujiang fault zone are listed.With these geothermal data and 37 other terrestrial heat flow values(previously published),we describe the distribution features of terrestrial heat flows in the area.In this research,the two-dimensional temperature structure from the surface to lithospheric bottom of the Huaibei-Sixian-Jinhu profile is inferred by using the finite-element method and the temperature and heat flow of sedimentary,granitic,and basaltic layers is calculated.
文摘A comprehensive discussion on the deep seated genesis of gold metallogenic materials and the tectono magmatic controls over gold deposits is given in this paper, which is based on the crustal and upper mantle structural characteristics of the Jiaodong massif, the property, activation history and styles of the Tancheng Lujiang fault zone, as well as a series of accompanying tectono magmatic events. Prediction for further prospecting gold deposits in the area is also made.
基金supported by the National Natural Science Foundation of China(No.90814002)the Natural Science Foundation of Shandong Province(No.Y2005E02)
文摘The great Tancheng earthquake of M81/2 occurred in 1668 was the largest seismic event ever recorded in history in eastern China. This study determines the fault geometry of this earthquake by inverting seismological data of present-day moderate-small earthquakes in the focal area. We relocated those earthquakes with the double-difference method and found focal mechanism solutions using gird test method. The inversion results are as follows： the strike is 21.6°, the dip angle is 89.5°, the slip angle is 170°, the fault length is about 160 km, the lower-boundary depth is about 32 km and the buried depth of upper boundary is about 4 km. This shows that the seismic fault is a NNE-trending upright right-lateral strike-slip fault and has cut through the crust. Moreover, the surface seismic fault, intensity distribution of the earthquake, earthquake-depth distribution and seismic-wave velocity profile in the focal area all verified our study result.
基金the National Natural Science Foundation of China(project 41790464)the China Postdoctoral Fund(BH2080000099).
文摘The Tan-Lu fault zone is a large NNE-trending fault zone in eastern China.Investigations of the structures of the fault zone and its surrounding areas have attracted much attention.In this study,we used dense-array ambient noise tomography to construct a threedimensional shear wave velocity model of shallow crust in an area about 80km×70km in Lujiang,Anhui Province,eastern China.For approximately one month we collected continuous ambient noise signals recorded by 90 short-period seismographs in the region,and obtained the short-period Rayleigh wave empirical Green's functions between stations by the cross-correlation method;we also extracted 0.5–8 s fundamental mode Rayleigh wave group velocity and phase velocity dispersion curves.Based on the direct surface wave tomography method,we jointly inverted the group velocity and phase velocity dispersion data of all paths and obtained the 3-D shear wave velocity structure in the depth range of 0–5 km.The results revealed important geological structural features of the study area.In the north region,the sedimentary center of the Hefei Basin—the southwestern part of the Chaohu Lake—shows a significant low-velocity anomaly to a depth of at least 5 km.The southwestern and southeastern regions of the array are the eastern margin of the Dabie orogenic belt and the intrusion area of Luzong volcanic rocks,respectively,and both show obvious high-speed anomalies;the sedimentary area within the Tan-Lu fault zone(about 10 km wide)shows low-velocity anomalies.However,the volcanic rock intrusion area in the fault zone is shown as high velocity.Our shallow crustal imaging results reflect the characteristics of different structures in the study area,especially the high-speed intrusive rocks in the Tan-Lu fault zone,which were probably partially derived from the magmatic activity of Luzong volcanic basin.From the Late Cretaceous to Early Tertiary,the Tan-Lu fault zone was in a period of extensional activity;the special stress environment and the fractured fault zone morphology provided conditions for magma in the Luzong volcanic basin to intrude into the Tan-Lu fault zone in the west.Our 3-D model can also provide important information for deep resource exploration and earthquake strong ground motion simulation.
基金This study is supported by funds from the Ministry of Science and Technology of China （2006CB403500） ； National Natural Science Foundation of China （40473021）.
文摘Four samples of plagioclase and biotite from the Shaxi porphyry in the lower part of the Yangtze metallogenic belt were analyzed for age determination with the ^40 Ar/^39Ar method. The results yield reproducible ages of 126 Ma to 135 Ma with a high level of confidence according to the agreement between isochron and plateau ages. The four Ar-Ar ages are relatively consistent within the analytical error. These ages are also consistent with, but more precise than, previous K-Ar and Rb-Sr ages and thus provide better constraints on the time of porphyry formation and associated Cu-Au mineralization along the middle to lower part of the Yangtze metallogenic belt. The ages of 126 to 135 Ma are interpreted to represent the intrusive time of the Shaxi porphyry, so that the Cu-Au mineralization should have occurred later due to the post-magmatic hydrothermal event.
