The Fenghuangshan Pluton is located in the Tongling polymineral-cluster district in the middle-lower section of the Yangtze metallogenic belt. In tectonic terms, it is in the middle of the Guichi-Fanchang faulted fold...The Fenghuangshan Pluton is located in the Tongling polymineral-cluster district in the middle-lower section of the Yangtze metallogenic belt. In tectonic terms, it is in the middle of the Guichi-Fanchang faulted fold bundle of the lower Yangtze Platform fold belt between the Dabie Orogenic Belt and the Jiangnan Massif. Analyses of the structural deformation characteristics of both the contact zone and the interior of the pluton are used to explain its emplacement mechanism. The foliation and lineation of the pluton, consisting of the oriented distribution of dark minerals and xenoliths, mainly concentrate along the margin of the pluton. Toward the center of the pluton, the foliation structure becomes weak, showing intense compression formation at the margin, and reflecting the conformable intrusion of the pluton. The relatively gentle lineation is evidence of a rotatory emplacement mechanism. Relatively steep marginal foliation reflects compression expanding. Affected by the thermal power of the pluton, the metamorphism of the contact zone has zonation. Both the strike of the axial plane of fold at the contact zone and that of the flow cleavage of the ductile shear zone are consistent with the boundary of the pluton, which reflects the speciality of conformable intrusion. The hinges of the folds are mostly inclined and erect, reflecting both the rotation of the pluton and its upward spiraling emplacement mechanism. Boudins developed in both the contact zone and the steep strata indicate the emplacement characteristic of the ballon expanding. The surrounding rock of the contact zone shortens horizontally. The average percentage of shortening is 39.7%, which further proves the mechanism of the pluton expanding, and the space occupied by the active expanding intrusion was provided by the shortening of the surrounding rock. The left-lateral shear shown by the ductile shear zone and the rheomorphic fold reveals that the pluton emplacement and the deformation of surrounding rock are controlled by a NNE-striking left-l展开更多
The Xinqiao S-Fe-Cu-Au orefield is located in the Tongling ore cluster in the middle and lower reaches of the Yangtze River in East China. There have been many researches regarding the genesis of the Xinqiao orefield ...The Xinqiao S-Fe-Cu-Au orefield is located in the Tongling ore cluster in the middle and lower reaches of the Yangtze River in East China. There have been many researches regarding the genesis of the Xinqiao orefield in recent years, showing that it belongs to various types, such as sedimentary-reformed type, stratabound-skarn type, sedimentary submarine rocks-hosted exhalative type. We propose that it was formed in two periods of mineralization base on systematic field observation and Pb and S isotopic analyses in nearly ten years. The first period was formed during a syngenetic sedimentary process, whereas the massive sulphide orebodies are mainly related to the Yanshanian granitic magmatism. Sulfide metallic mineral associations show zoning around a granite intrusion, i.e. magnetite and pyrite→pyrite, chalcopyrite and native gold→pyrite, sphalerite and galena. Gold orebodies occur outside the contact zone of the granite intrusion.展开更多
The central Fujian Province, situated on the juncture of paleo-uplift of Wuyishan, Yongmei Late Paleozoic depression and the eastern volcanic rift-faulting zone, is mainly composed of the outcropped metamorphic baseme...The central Fujian Province, situated on the juncture of paleo-uplift of Wuyishan, Yongmei Late Paleozoic depression and the eastern volcanic rift-faulting zone, is mainly composed of the outcropped metamorphic basements in the Middle-Late and Early Proterozoic, which constitute two upper and lower giant thick formations of Precambrian volcanic-sedimentary cycles, respectively. The formation of Dongyan Group is an important Middle-Upper Proterozoic component, and the Dongyan Group is directly related to massive sulfide deposit in this area. In recent years, plenty of lead, zinc, copper, silver and gold deposits have been found and explored. The Precambrian paleorift setting of the central Fujian Province served as a favorite metallogenic background for the formation of large- and superlarge-scale volcanic massive sulfide (VMS) lead and zinc polymetal deposits. The Dongyan Group consists chiefly of a set of ancient volcanic sedimentary formations that are composed mainly of greenschist. Its major lithologic types comprise greenschist, marble, quartzite and granofels class including various components. The metamorphic rocks of Dongyan Group are the main composition of Middle and Upper Proterozoic volcanic-sedimentary cycle. The original rock of Dongyan Group, a stable rock association, is volcanic sedimentation and normal marine sedimentation. But the original volcanic rocks, basic and acid, are bimodal. The volcanic rocks were formed in the extensional continental rift setting.展开更多
基金the Major State Basic Research Program(No.G1999043206)the Project of National Natrual Science Foundation of China(No.40372050) the Project of Resources Assessment of the China Geological Survey(No.200310200064).
文摘The Fenghuangshan Pluton is located in the Tongling polymineral-cluster district in the middle-lower section of the Yangtze metallogenic belt. In tectonic terms, it is in the middle of the Guichi-Fanchang faulted fold bundle of the lower Yangtze Platform fold belt between the Dabie Orogenic Belt and the Jiangnan Massif. Analyses of the structural deformation characteristics of both the contact zone and the interior of the pluton are used to explain its emplacement mechanism. The foliation and lineation of the pluton, consisting of the oriented distribution of dark minerals and xenoliths, mainly concentrate along the margin of the pluton. Toward the center of the pluton, the foliation structure becomes weak, showing intense compression formation at the margin, and reflecting the conformable intrusion of the pluton. The relatively gentle lineation is evidence of a rotatory emplacement mechanism. Relatively steep marginal foliation reflects compression expanding. Affected by the thermal power of the pluton, the metamorphism of the contact zone has zonation. Both the strike of the axial plane of fold at the contact zone and that of the flow cleavage of the ductile shear zone are consistent with the boundary of the pluton, which reflects the speciality of conformable intrusion. The hinges of the folds are mostly inclined and erect, reflecting both the rotation of the pluton and its upward spiraling emplacement mechanism. Boudins developed in both the contact zone and the steep strata indicate the emplacement characteristic of the ballon expanding. The surrounding rock of the contact zone shortens horizontally. The average percentage of shortening is 39.7%, which further proves the mechanism of the pluton expanding, and the space occupied by the active expanding intrusion was provided by the shortening of the surrounding rock. The left-lateral shear shown by the ductile shear zone and the rheomorphic fold reveals that the pluton emplacement and the deformation of surrounding rock are controlled by a NNE-striking left-l
基金the State Key Basic Research Program of China(No.G1999043206)the National Natural Science Foundation of China(No.40372050)+1 种基金the Project of Resources Assessment of the Geological Surveyof China(No.200310200064) the Key Laboratory of Lithospheric Tectonics and Lithoprobing Technology.
文摘The Xinqiao S-Fe-Cu-Au orefield is located in the Tongling ore cluster in the middle and lower reaches of the Yangtze River in East China. There have been many researches regarding the genesis of the Xinqiao orefield in recent years, showing that it belongs to various types, such as sedimentary-reformed type, stratabound-skarn type, sedimentary submarine rocks-hosted exhalative type. We propose that it was formed in two periods of mineralization base on systematic field observation and Pb and S isotopic analyses in nearly ten years. The first period was formed during a syngenetic sedimentary process, whereas the massive sulphide orebodies are mainly related to the Yanshanian granitic magmatism. Sulfide metallic mineral associations show zoning around a granite intrusion, i.e. magnetite and pyrite→pyrite, chalcopyrite and native gold→pyrite, sphalerite and galena. Gold orebodies occur outside the contact zone of the granite intrusion.
文摘The central Fujian Province, situated on the juncture of paleo-uplift of Wuyishan, Yongmei Late Paleozoic depression and the eastern volcanic rift-faulting zone, is mainly composed of the outcropped metamorphic basements in the Middle-Late and Early Proterozoic, which constitute two upper and lower giant thick formations of Precambrian volcanic-sedimentary cycles, respectively. The formation of Dongyan Group is an important Middle-Upper Proterozoic component, and the Dongyan Group is directly related to massive sulfide deposit in this area. In recent years, plenty of lead, zinc, copper, silver and gold deposits have been found and explored. The Precambrian paleorift setting of the central Fujian Province served as a favorite metallogenic background for the formation of large- and superlarge-scale volcanic massive sulfide (VMS) lead and zinc polymetal deposits. The Dongyan Group consists chiefly of a set of ancient volcanic sedimentary formations that are composed mainly of greenschist. Its major lithologic types comprise greenschist, marble, quartzite and granofels class including various components. The metamorphic rocks of Dongyan Group are the main composition of Middle and Upper Proterozoic volcanic-sedimentary cycle. The original rock of Dongyan Group, a stable rock association, is volcanic sedimentation and normal marine sedimentation. But the original volcanic rocks, basic and acid, are bimodal. The volcanic rocks were formed in the extensional continental rift setting.
