The paleocontinental margins have frequent and intensive tectonic movement and various ore forming processes. According to their tectono dynamic characteristics, the paleocontinental margins can be classified into t...The paleocontinental margins have frequent and intensive tectonic movement and various ore forming processes. According to their tectono dynamic characteristics, the paleocontinental margins can be classified into three types: the divergent, the convergent and the transformational. Each type has its specific geological geochemical processes and metallogenic system. The paper discusses the tectonic evolution and ore forming features of the North China block margins, puts forward conceptions such as complexity, variety and multi stage development of metallogenic evolution in the paleocontinental margins, and expounds five factors controlling the formation of large superlarge ore deposits in the paleocontinental margins: (1) channelway, (2) rendezvous of fluids, (3) abundance of ore source, (4) thermo dynamic anomaly, (5) long duration of structural activities.展开更多
Several stratigraphic breaks and unconformities exist in the Mesoproterozoic successions in the northern margin of the North China Block. Geologic characters and spatial distributions of five of these un- conformities...Several stratigraphic breaks and unconformities exist in the Mesoproterozoic successions in the northern margin of the North China Block. Geologic characters and spatial distributions of five of these un- conformities, which have resulted from different geological processes, have been studied. The uncon- formity beneath the Dahongyu Formation is interpreted as a breakup unconformity, representing the time of transition from continental rift to passive continental margin. The unconformities beneath the Gaoyuzhuang and the Yangzhuang formations are considered to be the consequence of regional eustatic fluctuations, leading to the exposure of highlands in passive margins during low sea-level stands and transgressive deposition on coastal regions during high sea-level stands. The unconformity atop the Tieling Formation might be caused by uplift due to contractional deformation in a back-arc setting, whereas the uplift after the deposition of the Xiamaling Formation might be attributed to a continental collision event. It is assumed that the occurrences of these unconformities in the Mesoproterozoic successions in the northern margin of the North China Block had a close bearing on the assemblage and breakup of the Columbia and Rodinia supercontinents.展开更多
Objective Indosinian magmatic rocks mainly locate in west Qinling Orogen, which are, however, extremely rare in east Qingling Orogen （Lu Xinxiang, 2000; Zhang Guowei et al., 2001; Guo Xianqing et al., 2017）. The Zh...Objective Indosinian magmatic rocks mainly locate in west Qinling Orogen, which are, however, extremely rare in east Qingling Orogen （Lu Xinxiang, 2000; Zhang Guowei et al., 2001; Guo Xianqing et al., 2017）. The Zhifang Huangzhuang （ZH） area in south Songxian County is located in the southern margin of the North China Craton （Fig. l a）, which is an important lndosinian alkaline magmatic occurrence including 32 syenite bodies and syenitic dykes in east Qinling Orogen. There are five syenite bodes in the ZH area, i.e., the Lang＇aogou, Mogou, Longtou, Jiaogou and Wusanggou from west to east （Fig. l b）.展开更多
1 Introduction Voluminous Mesozoic magmatic rocks containing abundant Au-Mo polymetallic mineralization resources are developed in the Xiaoqinling-Xiong’ershan district of the southern margin of the North China Crato...1 Introduction Voluminous Mesozoic magmatic rocks containing abundant Au-Mo polymetallic mineralization resources are developed in the Xiaoqinling-Xiong’ershan district of the southern margin of the North China Craton(NCC).展开更多
1 Introduction The Wulong glomerophyric diorite porphyry has an extremely peculiar texture with plagioclase phenocrysts clustered as flower-like glomerocrysts(Figs.1a&b),which is never discovered elsewhere of the ...1 Introduction The Wulong glomerophyric diorite porphyry has an extremely peculiar texture with plagioclase phenocrysts clustered as flower-like glomerocrysts(Figs.1a&b),which is never discovered elsewhere of the world.The展开更多
The Paleoproterozoic Xiong’er Group is composed of mafic to felsic volcanic rocks and minor sedimentary rocks,distributed along the southern margin of the North China craton(NCC).It is a key marker for regional
Gold is commonly associated with arsenic in As-rich pyrite or arsenopyrite in a variety types of gold deposit,such as sediment-hosted gold deposits,epithermal Au-Ag deposits,Au-rich VMS deposits,and mesothermal lode g...Gold is commonly associated with arsenic in As-rich pyrite or arsenopyrite in a variety types of gold deposit,such as sediment-hosted gold deposits,epithermal Au-Ag deposits,Au-rich VMS deposits,and mesothermal lode gold deposits(Ciobanu and Cook,2002;Pals et al.展开更多
Soft-sediment deformation structures are abundant in the Cambrian Zhushadong and Mantou formations of the Dengfeng area, Henan Province, China. Soft-sediment deformation structures of the Zhushadong Formation consist ...Soft-sediment deformation structures are abundant in the Cambrian Zhushadong and Mantou formations of the Dengfeng area, Henan Province, China. Soft-sediment deformation structures of the Zhushadong Formation consist of fluidized deformation, synsedimentary faults, seismo-folds and plastic deformation; the Mantou Formation is dominated by small-scale horst faults, intruded dikes, fluidized veins, and seismo-cracks. These structures are demonstrated to be earthquake-related by analysis of trigger mechanisms, and may indicate the activity of the Qinling tectonic belt during the early Cambrian. Furthermore, the assemblages of soft-sediment deformation structures altered with time： large-scale, intense deformation in the Zhushadong Formation alters to small-scale, weak deformation in the Mantou Formation. This striking feature may have been caused by changes in hypocentral depth from deep-focus to shallow-focus earthquakes, indicating that the Qinling tectonic belt developed from the subduction of the Shangdan Ocean to the extension of the Erlangping back-arc basin. This study suggests that soft-sediment deformation structures can be used to reveal the activity of a tectonic belt, and, more importantly, changes in deformation assemblages can track the evolution of a tectonic belt.展开更多
Late Carboniferous fossils(such as Boultonia? sp., Tabulata, and spiriferoid specimens with smooth shells), bioclastic material(such as crinoid stems and sponge fragments), and Late Ordovician microfossils of the cono...Late Carboniferous fossils(such as Boultonia? sp., Tabulata, and spiriferoid specimens with smooth shells), bioclastic material(such as crinoid stems and sponge fragments), and Late Ordovician microfossils of the conodont Belodina have been discovered in the lower part of the strata typically referred to as the Neoproterozoic on the boundary of the provinces of Anhui and Henan in the southern margin of the North China Block. These findings prove that the strata contain macrofossils belonging to the Late Carboniferous, which belonged to a carbonate debris flow deposit that was formed under a carbonate slope environment. The conodont fossils might belong to a detrital deposit. Thus, it is possible to reset the stratigraphic sequences and tectonic attributes belonging to the North Huaiyang tectonic belt and limit the Shouxian fault to the boundary between the Dabie Orogen and North China Block.展开更多
Late Mesozoic granitic magmatism(158–112 Ma) are widespread in the southern margin of the North China Craton(NCC), contemporary with many world-class Mo-Au-Ag-Pb-Zn polymetallic deposits. There are abrupt changes in ...Late Mesozoic granitic magmatism(158–112 Ma) are widespread in the southern margin of the North China Craton(NCC), contemporary with many world-class Mo-Au-Ag-Pb-Zn polymetallic deposits. There are abrupt changes in the elements and isotopic compositions of these granites at about 127 Ma. The early stage(158–128 Ma) granites show slightly or no negative Eu anomalies, large ion lithophile elements enriched and heavy REE depleted(such as Y and Yb), belonging to typical I-type granite. The late stage(126–112 Ma) granites are characterized by A-type and/or highly fractionated I-type granite, with higher contents of SiO2, K2 O, Y, Yb and Rb/Sr ratio and lower contents of Sr, δEu value and Sr/Y ratio than that of the early-stage granites.Moreover, the whole rock Nd and Hf isotopic compositions of the granites younger than 127 Ma show more depleted than those of the older one. The two stages of Late Mesozoic granites were derived from a source region of the ancient basement of the southern margin of the NCC incorporated the mantle material. The late stage(126–112 Ma) granites contain more fractions of mantle material with depleted isotopic composition than the early ones. The granites record evidence for a strong crust-mantle interaction. They formed in an intracontinental extensional setting which was related to lithospheric thinning and asthenospheric upwelling in this region, which was possibly caused by westward subduction of the Paleo-Pacific plate. 127 Ma is an critical period of the transformation of the tectonic regime.展开更多
The helium and argon isotopic compositions of the ore-forming fluids from the molybdenum deposits such as Jinduicheng, Donggou, Shijiawan, and Sandaozhuang, which are located in the East Qinling molybdenum belt in sou...The helium and argon isotopic compositions of the ore-forming fluids from the molybdenum deposits such as Jinduicheng, Donggou, Shijiawan, and Sandaozhuang, which are located in the East Qinling molybdenum belt in south margin of North China Block (SMCNB), are reported in this paper. The origin and the evolution of the ore-forming fluids and their coupled-relationships with the intra-continental collision and orogenic process of Qinling Orogen in Mesozoic-Cenozoic have been discussed. The 3He/4He and 40Ar/36Ar values (3He/4He=1.38―3.64 Ra, and 40Ar/36Ar=295.68―346.39, respectively) of the fluid inclusions in pyrite from the molybdenum deposits in East Qinling suggest that, the ore-forming fluid system is mixed by two end members. One is the high temperature deep-derived fluid congenetic with the porphyries generated by crust-mantle mixing, and the other is the low-temperature meteoric water which is rich in crustal radiogenic He with the component of atmospheric Ar. From the Pb isotopic composition, and ore-bearing potential of the porphyry and the regional stratum, we can conclude that the ore-forming materials of the deposits in the East Qinling molybdenum belt are derived from the deep source by the mixing of lower crust and upper mantle. Therefore, the formation of the molybdenum deposits in SMNCB can be related to the crust-mantle interaction, which is accompanied by the intra-continental orogenic and extension process in the post-collision period of Qinling Orogen. The granitic porphyries which are related to Mo mineralization are not simple crust-remelting type granites or S type granites, but belong to syntexis-type or mantle-derived granites, hence their formation has a profound and regional geodynamic background.展开更多
文摘The paleocontinental margins have frequent and intensive tectonic movement and various ore forming processes. According to their tectono dynamic characteristics, the paleocontinental margins can be classified into three types: the divergent, the convergent and the transformational. Each type has its specific geological geochemical processes and metallogenic system. The paper discusses the tectonic evolution and ore forming features of the North China block margins, puts forward conceptions such as complexity, variety and multi stage development of metallogenic evolution in the paleocontinental margins, and expounds five factors controlling the formation of large superlarge ore deposits in the paleocontinental margins: (1) channelway, (2) rendezvous of fluids, (3) abundance of ore source, (4) thermo dynamic anomaly, (5) long duration of structural activities.
文摘Several stratigraphic breaks and unconformities exist in the Mesoproterozoic successions in the northern margin of the North China Block. Geologic characters and spatial distributions of five of these un- conformities, which have resulted from different geological processes, have been studied. The uncon- formity beneath the Dahongyu Formation is interpreted as a breakup unconformity, representing the time of transition from continental rift to passive continental margin. The unconformities beneath the Gaoyuzhuang and the Yangzhuang formations are considered to be the consequence of regional eustatic fluctuations, leading to the exposure of highlands in passive margins during low sea-level stands and transgressive deposition on coastal regions during high sea-level stands. The unconformity atop the Tieling Formation might be caused by uplift due to contractional deformation in a back-arc setting, whereas the uplift after the deposition of the Xiamaling Formation might be attributed to a continental collision event. It is assumed that the occurrences of these unconformities in the Mesoproterozoic successions in the northern margin of the North China Block had a close bearing on the assemblage and breakup of the Columbia and Rodinia supercontinents.
基金supported by the National Nature Science Foundation of China(grant No.U1504405)
文摘Objective Indosinian magmatic rocks mainly locate in west Qinling Orogen, which are, however, extremely rare in east Qingling Orogen （Lu Xinxiang, 2000; Zhang Guowei et al., 2001; Guo Xianqing et al., 2017）. The Zhifang Huangzhuang （ZH） area in south Songxian County is located in the southern margin of the North China Craton （Fig. l a）, which is an important lndosinian alkaline magmatic occurrence including 32 syenite bodies and syenitic dykes in east Qinling Orogen. There are five syenite bodes in the ZH area, i.e., the Lang＇aogou, Mogou, Longtou, Jiaogou and Wusanggou from west to east （Fig. l b）.
基金supported by the NSFC (41373039)the DREAM project of MOST, China (2016YFC0600403)
文摘1 Introduction Voluminous Mesozoic magmatic rocks containing abundant Au-Mo polymetallic mineralization resources are developed in the Xiaoqinling-Xiong’ershan district of the southern margin of the North China Craton(NCC).
基金financially supported by the National Natural Science Foundation of China(No.41502046,41530211 and 41272079)
文摘1 Introduction The Wulong glomerophyric diorite porphyry has an extremely peculiar texture with plagioclase phenocrysts clustered as flower-like glomerocrysts(Figs.1a&b),which is never discovered elsewhere of the world.The
文摘The Paleoproterozoic Xiong’er Group is composed of mafic to felsic volcanic rocks and minor sedimentary rocks,distributed along the southern margin of the North China craton(NCC).It is a key marker for regional
基金supported by the Natural Science Foundation of China(grants 9081400440821061)the 111 Project(B07039)
文摘Gold is commonly associated with arsenic in As-rich pyrite or arsenopyrite in a variety types of gold deposit,such as sediment-hosted gold deposits,epithermal Au-Ag deposits,Au-rich VMS deposits,and mesothermal lode gold deposits(Ciobanu and Cook,2002;Pals et al.
基金granted by the doctor foundation of Henan Polytechnic University(NO:B2013-076)the National Nature Science Foundation of China(NO:4147208341440016)
文摘Soft-sediment deformation structures are abundant in the Cambrian Zhushadong and Mantou formations of the Dengfeng area, Henan Province, China. Soft-sediment deformation structures of the Zhushadong Formation consist of fluidized deformation, synsedimentary faults, seismo-folds and plastic deformation; the Mantou Formation is dominated by small-scale horst faults, intruded dikes, fluidized veins, and seismo-cracks. These structures are demonstrated to be earthquake-related by analysis of trigger mechanisms, and may indicate the activity of the Qinling tectonic belt during the early Cambrian. Furthermore, the assemblages of soft-sediment deformation structures altered with time： large-scale, intense deformation in the Zhushadong Formation alters to small-scale, weak deformation in the Mantou Formation. This striking feature may have been caused by changes in hypocentral depth from deep-focus to shallow-focus earthquakes, indicating that the Qinling tectonic belt developed from the subduction of the Shangdan Ocean to the extension of the Erlangping back-arc basin. This study suggests that soft-sediment deformation structures can be used to reveal the activity of a tectonic belt, and, more importantly, changes in deformation assemblages can track the evolution of a tectonic belt.
基金supported by funds from the China Geological Survey(12120113094300)the National Natural Science Foundation of China(40972082 and 41172097)
文摘Late Carboniferous fossils(such as Boultonia? sp., Tabulata, and spiriferoid specimens with smooth shells), bioclastic material(such as crinoid stems and sponge fragments), and Late Ordovician microfossils of the conodont Belodina have been discovered in the lower part of the strata typically referred to as the Neoproterozoic on the boundary of the provinces of Anhui and Henan in the southern margin of the North China Block. These findings prove that the strata contain macrofossils belonging to the Late Carboniferous, which belonged to a carbonate debris flow deposit that was formed under a carbonate slope environment. The conodont fossils might belong to a detrital deposit. Thus, it is possible to reset the stratigraphic sequences and tectonic attributes belonging to the North Huaiyang tectonic belt and limit the Shouxian fault to the boundary between the Dabie Orogen and North China Block.
基金supported by the National Key Research and Development Program of China(Grant No.2016YFC0600106)the National Natural Science Foundation of China(Grant Nos.41402047&41373046)
文摘Late Mesozoic granitic magmatism(158–112 Ma) are widespread in the southern margin of the North China Craton(NCC), contemporary with many world-class Mo-Au-Ag-Pb-Zn polymetallic deposits. There are abrupt changes in the elements and isotopic compositions of these granites at about 127 Ma. The early stage(158–128 Ma) granites show slightly or no negative Eu anomalies, large ion lithophile elements enriched and heavy REE depleted(such as Y and Yb), belonging to typical I-type granite. The late stage(126–112 Ma) granites are characterized by A-type and/or highly fractionated I-type granite, with higher contents of SiO2, K2 O, Y, Yb and Rb/Sr ratio and lower contents of Sr, δEu value and Sr/Y ratio than that of the early-stage granites.Moreover, the whole rock Nd and Hf isotopic compositions of the granites younger than 127 Ma show more depleted than those of the older one. The two stages of Late Mesozoic granites were derived from a source region of the ancient basement of the southern margin of the NCC incorporated the mantle material. The late stage(126–112 Ma) granites contain more fractions of mantle material with depleted isotopic composition than the early ones. The granites record evidence for a strong crust-mantle interaction. They formed in an intracontinental extensional setting which was related to lithospheric thinning and asthenospheric upwelling in this region, which was possibly caused by westward subduction of the Paleo-Pacific plate. 127 Ma is an critical period of the transformation of the tectonic regime.
基金Supported by the National Basic Research Program of China (Grant No. 2006CB403502)National Natural Science Foundation of China (Grant No.40872071)+1 种基金Program of State Key Laboratory of Ore Deposit Geochemistry, Chinese Academy of Sciences (Grant No. 20060)Fundation of Educational Bureau of Shaanxi Province (Grant No. 07JK414)
文摘The helium and argon isotopic compositions of the ore-forming fluids from the molybdenum deposits such as Jinduicheng, Donggou, Shijiawan, and Sandaozhuang, which are located in the East Qinling molybdenum belt in south margin of North China Block (SMCNB), are reported in this paper. The origin and the evolution of the ore-forming fluids and their coupled-relationships with the intra-continental collision and orogenic process of Qinling Orogen in Mesozoic-Cenozoic have been discussed. The 3He/4He and 40Ar/36Ar values (3He/4He=1.38―3.64 Ra, and 40Ar/36Ar=295.68―346.39, respectively) of the fluid inclusions in pyrite from the molybdenum deposits in East Qinling suggest that, the ore-forming fluid system is mixed by two end members. One is the high temperature deep-derived fluid congenetic with the porphyries generated by crust-mantle mixing, and the other is the low-temperature meteoric water which is rich in crustal radiogenic He with the component of atmospheric Ar. From the Pb isotopic composition, and ore-bearing potential of the porphyry and the regional stratum, we can conclude that the ore-forming materials of the deposits in the East Qinling molybdenum belt are derived from the deep source by the mixing of lower crust and upper mantle. Therefore, the formation of the molybdenum deposits in SMNCB can be related to the crust-mantle interaction, which is accompanied by the intra-continental orogenic and extension process in the post-collision period of Qinling Orogen. The granitic porphyries which are related to Mo mineralization are not simple crust-remelting type granites or S type granites, but belong to syntexis-type or mantle-derived granites, hence their formation has a profound and regional geodynamic background.
