The late Neoarchean metamorphosed volcanic rocks in the southern Liaoning Terrane(SLT) of the eastern North China Craton(NCC) are mainly composed of amphibolites and felsic gneisses and can be chemically classified as...The late Neoarchean metamorphosed volcanic rocks in the southern Liaoning Terrane(SLT) of the eastern North China Craton(NCC) are mainly composed of amphibolites and felsic gneisses and can be chemically classified as basalt(Group#1),basaltic andesite(Group#2),dacite(Group#3) and rhyodacite(Group#4).LA-ICP-MS zircon U-Th-Pb dating reveals that they formed at ~2.53-2.51 Ga.Group#1 samples are characterized by approximately flat chondrite-normalized rare earth element(REE) patterns with low(La/Yb)_N ratios and a narrow range of(Hf/Sm)N ratios,and their magmatic precursors were generated by partial melting of a depleted mantle wedge weakly metasomatized by subducted slab fluids.Compared to Group#1 samples,Group#2 samples display strongly fractionated REE patterns with higher(La/Yb)_N ratios and more scattered(Hf/Sm)N ratios,indicative of a depleted mantle wedge that had been intensely metasomatized by slab-derived melts and fluids.Group#3 samples are characterized by high MgO and transition trace element concentrations and fractionated REE patterns,which resemble typical high-Si adakites,and the magmatic precursors were derived from partial melting of a subducted oceanic slab.Group#4 samples have the highest SiO_2 and the lowest MgO and transition trace element contents,and were derived from partial melting of basaltic rocks at lower crust levels.Integrating these tholeiitic to calcalkaline volcanic rocks with the mass of contemporaneous dioritic-tonalitic-trondhjemitic-granodioritic gneisses,the late Neoarchean volcanic rocks in the SLT were most likely produced in an active continental margin.Furthermore,the affinities in lithological assemblages,metamorphism and tectonic regime among SLT,eastern Hebei to western Liaoning Terrane(EH-WLT),northern Liaoning to southern Jilin Terrane(NL-SJT),AnshanBenxi continental nucleus(ABN) and Yishui complex(YSC) collectively indicate that an integral and much larger continental block had been formed in the late Neoarchean and the craton-scale lateral accretion was a dominantly geodynamic mechanism in the eastern NCC.展开更多
The Mesozoic Yanshanian Movement affected the tectonic evolution of the North China Craton(NCC).It is proposed that Mesozoic cratonic destruction peaked~125 Ma,possibly influenced by subduction of the western Pacific ...The Mesozoic Yanshanian Movement affected the tectonic evolution of the North China Craton(NCC).It is proposed that Mesozoic cratonic destruction peaked~125 Ma,possibly influenced by subduction of the western Pacific Plate beneath the Euro-Asian Plate in the Early Cretaceous.The southern Jinzhou area in the eastern block of the NCC preserves clues about the tectonic events and related geological resources.Studies of the regional stress field evolution from the Cretaceous to the Cenozoic can enhance our understanding of the tectonics and dynamics of the NCC.Borehole image logging technology was used to identify and collect attitudes of tensile fractures from 11 boreholes;these were subdivided into four groups according to dip direction,i.e.,NNW-SSE,NWW-SEE,W-E and NE-SW.The development of these fractures was controlled primarily by the regional tectonic stress field;temperature,lithology,and depth contributed to some extent.In 136-125 Ma in the Early Cretaceous,the area was characterized by extension that was oriented NNW-SSE and NWW-SEE;from 125-101 Ma the extension was oriented W-E;after 101 Ma it was NE-SW.This counterclockwise trend has persisted to the present,probably related to oblique subduction of the Pacific Plate,and is characterized by ongoing extension that is nearly N-S-oriented and NEE-SWW-oriented compression.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
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 North China Craton is the oldest continental block,and has suffered from large-scale lithospheric thinning and destruction,which in turn led to gold deposits in northern China.The decratonic gold deposits in the N...The North China Craton is the oldest continental block,and has suffered from large-scale lithospheric thinning and destruction,which in turn led to gold deposits in northern China.The decratonic gold deposits in the North China Craton became the most important gold deposits in China,and geophysical methods are key means to detect and discover gold deposits there.In this paper,based on the geological and petrophysical characteristics of the North China Craton,the geological model of the decratonic gold deposits is transformed into a geophysical model.At present,two methods of geophysical exploration of decratonic gold deposits are in use:rapid and efficient exploration on the scale of the ore concentration area,and large depth exploration on the scale of the deposit area.In detail,the airborne electromagnetic,magnetic and gravity methods are used to detect the shallow(1,500 m)anomaly area on the scale of the ore concentration area.Through the ground-controlled source electromagnetic and ground magnetotelluric methods,explorations for targets at significant depth(5,000 m)are carried out in the mining area.Then,taking the Liaodong ore concentration area as an example,geophysical methods are used to discover two prospecting areas around the Jianshanzi Fault in the Qingchengzi ore concentration area,Baiyun-Xiaotongjiapuzi deep prospecting area,and Qingchengzi deep prospecting area.Next,three prospecting areas are delineated around the Jixingou Fault in the Wulong mining area,Wulong deep prospecting area,Weishagou deep prospecting area,and Chang’an deep prospecting area.The anomalies in the ore concentration area and mining area are revealed by means of three-dimensional exploration methods,thereby providing technical support for the exploration of metal minerals such as decratonic gold deposits.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41530207 and 41772188)。
文摘The late Neoarchean metamorphosed volcanic rocks in the southern Liaoning Terrane(SLT) of the eastern North China Craton(NCC) are mainly composed of amphibolites and felsic gneisses and can be chemically classified as basalt(Group#1),basaltic andesite(Group#2),dacite(Group#3) and rhyodacite(Group#4).LA-ICP-MS zircon U-Th-Pb dating reveals that they formed at ~2.53-2.51 Ga.Group#1 samples are characterized by approximately flat chondrite-normalized rare earth element(REE) patterns with low(La/Yb)_N ratios and a narrow range of(Hf/Sm)N ratios,and their magmatic precursors were generated by partial melting of a depleted mantle wedge weakly metasomatized by subducted slab fluids.Compared to Group#1 samples,Group#2 samples display strongly fractionated REE patterns with higher(La/Yb)_N ratios and more scattered(Hf/Sm)N ratios,indicative of a depleted mantle wedge that had been intensely metasomatized by slab-derived melts and fluids.Group#3 samples are characterized by high MgO and transition trace element concentrations and fractionated REE patterns,which resemble typical high-Si adakites,and the magmatic precursors were derived from partial melting of a subducted oceanic slab.Group#4 samples have the highest SiO_2 and the lowest MgO and transition trace element contents,and were derived from partial melting of basaltic rocks at lower crust levels.Integrating these tholeiitic to calcalkaline volcanic rocks with the mass of contemporaneous dioritic-tonalitic-trondhjemitic-granodioritic gneisses,the late Neoarchean volcanic rocks in the SLT were most likely produced in an active continental margin.Furthermore,the affinities in lithological assemblages,metamorphism and tectonic regime among SLT,eastern Hebei to western Liaoning Terrane(EH-WLT),northern Liaoning to southern Jilin Terrane(NL-SJT),AnshanBenxi continental nucleus(ABN) and Yishui complex(YSC) collectively indicate that an integral and much larger continental block had been formed in the late Neoarchean and the craton-scale lateral accretion was a dominantly geodynamic mechanism in the eastern NCC.
基金supported by the National Natural Science Foundation of China(41574088)。
文摘The Mesozoic Yanshanian Movement affected the tectonic evolution of the North China Craton(NCC).It is proposed that Mesozoic cratonic destruction peaked~125 Ma,possibly influenced by subduction of the western Pacific Plate beneath the Euro-Asian Plate in the Early Cretaceous.The southern Jinzhou area in the eastern block of the NCC preserves clues about the tectonic events and related geological resources.Studies of the regional stress field evolution from the Cretaceous to the Cenozoic can enhance our understanding of the tectonics and dynamics of the NCC.Borehole image logging technology was used to identify and collect attitudes of tensile fractures from 11 boreholes;these were subdivided into four groups according to dip direction,i.e.,NNW-SSE,NWW-SEE,W-E and NE-SW.The development of these fractures was controlled primarily by the regional tectonic stress field;temperature,lithology,and depth contributed to some extent.In 136-125 Ma in the Early Cretaceous,the area was characterized by extension that was oriented NNW-SSE and NWW-SEE;from 125-101 Ma the extension was oriented W-E;after 101 Ma it was NE-SW.This counterclockwise trend has persisted to the present,probably related to oblique subduction of the Pacific Plate,and is characterized by ongoing extension that is nearly N-S-oriented and NEE-SWW-oriented compression.
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 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 Key Research and Development Program“Deep Earth Resources Exploration and Exploitation”(Grant No.2016YFC0600101)the Beijing Science and Technology Program“Deep Earth Exploration Technology Research and Development”Special Funding(Grant No.Z181100005718001)the National Natural Science Foundation Key Project(Grant No.42030106)。
文摘The North China Craton is the oldest continental block,and has suffered from large-scale lithospheric thinning and destruction,which in turn led to gold deposits in northern China.The decratonic gold deposits in the North China Craton became the most important gold deposits in China,and geophysical methods are key means to detect and discover gold deposits there.In this paper,based on the geological and petrophysical characteristics of the North China Craton,the geological model of the decratonic gold deposits is transformed into a geophysical model.At present,two methods of geophysical exploration of decratonic gold deposits are in use:rapid and efficient exploration on the scale of the ore concentration area,and large depth exploration on the scale of the deposit area.In detail,the airborne electromagnetic,magnetic and gravity methods are used to detect the shallow(1,500 m)anomaly area on the scale of the ore concentration area.Through the ground-controlled source electromagnetic and ground magnetotelluric methods,explorations for targets at significant depth(5,000 m)are carried out in the mining area.Then,taking the Liaodong ore concentration area as an example,geophysical methods are used to discover two prospecting areas around the Jianshanzi Fault in the Qingchengzi ore concentration area,Baiyun-Xiaotongjiapuzi deep prospecting area,and Qingchengzi deep prospecting area.Next,three prospecting areas are delineated around the Jixingou Fault in the Wulong mining area,Wulong deep prospecting area,Weishagou deep prospecting area,and Chang’an deep prospecting area.The anomalies in the ore concentration area and mining area are revealed by means of three-dimensional exploration methods,thereby providing technical support for the exploration of metal minerals such as decratonic gold deposits.
