Multistage deformation events have occurred in the northeastern Jiangshao Fault （Suture） Belt. The earliest two are ductile deformation events. The first is the ca. 820 Ma top-to-the-northwest ductile thrusting, whi...Multistage deformation events have occurred in the northeastern Jiangshao Fault （Suture） Belt. The earliest two are ductile deformation events. The first is the ca. 820 Ma top-to-the-northwest ductile thrusting, which directly resulted from the collision between the Cathaysia Old Land and the Chencai Arc （？） during the Late Neoproterozoic, and the Jiangnan Orogenic Belt that formed as the ocean closed between the Yangtze Plate and the jointed Cathaysia Old Land and the Chencai Arc due to continuous compression. The second is the ductile left-lateral strike-slipping that occurred in the latest Early Paleozoic. Since the Jinning period, all deformation events represent the reactivation or inversion of intraplate structures due to the collisions between the North China and Yangtze plates during the Triassic and between the Philippine Sea and Eurasian plates during the Cenozoic. In the Triassic, brittle right-lateral strike-slipping and subsequent top-to-the south thrusting occurred along the whole northeastern Jiangshao Fault Zone because of the collision between the North China and Yangtze plates. In the Late Mesozoic, regional extension took place across southeastern China. In the Cenozoic, the collision between the Philippine Sea and Eurasian plates resulted in brittle thrusts along the whole Jiangnan Old land in the Miocene. The Jiangshao Fault Belt is a weak zone in the crust with long history, and its reactivation is one of important characteristics of the deformation in South China; however, late-stage deformation events did not occur beyond the Jiangnan Old Land and most of them are parallel to the strike of the Old Land, which is similar to the Cenozoic deformation in Central Asia. In addition, the Jiangnan old Land is not a collisional boundary between the Yangtze Plate and Cathaysia Old Land in the Triassic.展开更多
The Cathaysla flora, one of the most prominent floras of the Carboniferous and Permian, was mainly distributed In East Asia and was characterized by numerous endemic elements. China Is one of the most Important locali...The Cathaysla flora, one of the most prominent floras of the Carboniferous and Permian, was mainly distributed In East Asia and was characterized by numerous endemic elements. China Is one of the most Important localities of the Cathaysla flora and It ;s also the center of origin of this flora. This paper reviews and discusses the characteristics of the Cathaysla flora and the blogeographlcally mixed Permian Cathayslan-Angaran floras of East Asia. In addition, the formative mechanism of the mixed Permian floras Is also discussed.展开更多
The Eastern Guangxi area locates in the southwestern part of the transition zone between Yangtze and Cathaysia blocks, which is an important region because the boundary between two blocks probablycrosses there. We det...The Eastern Guangxi area locates in the southwestern part of the transition zone between Yangtze and Cathaysia blocks, which is an important region because the boundary between two blocks probablycrosses there. We determined LA-ICPMS U-Pb ages for detrital zircons extracted from three sandstone samples in the Sinian-Cambrian strata in this region. The resulting ages are in the range of the Archeozoic and Neoproterozoic, with three notable concentrates at 991 Ma, 974 Ma, and 964 Ma, all of which are coeval to the Grenvillian magmatic activity. The new age distribution is similar to the data reported in the Precambrian strata of the adjacent southwestern Cathaysia Block, suggesting that most of our detrital zircons are likely derived from the Cathaysia Block. Combined with others＇ research, we are more inclined to accept the opinion that there was not an ocean basin between the two blocks during the Sinian-Cambrian period in Eastern Guangxi area if the timing of collision is the Early Neoproterzoic. But if the timing of collision is the Early Paleozoic, we conclude that Luzhai uplift（i.e., the uplift between Guilin-Yongfu faultand Lipu fault） beyond the west of Dayaoshan regoin might be one part of southwestern sedimentation boundary of Cathaysia Block and Yangtze Block. We also get a few of detrital zircons with ages of ~590 Ma which probably sourced from northeastern Gondwana and 13 detrital zircons with over 3 000 Ma U-Pb ages which record the early formation of the earth.展开更多
Five Paleogene volcanics sampled from the northern South China Sea were analyzed via LA-ICP-MS zircon U-Pb dating, including basalt and andesite from Borehole SCSVI and volcanic agglomerate from Borehole SCSV2, respec...Five Paleogene volcanics sampled from the northern South China Sea were analyzed via LA-ICP-MS zircon U-Pb dating, including basalt and andesite from Borehole SCSVI and volcanic agglomerate from Borehole SCSV2, respectively. A total of 162 zircon U-Pb dates for them cover an age range from Neoarchean to Eocene, in which the pre-Paleocene data dominate. The Paleogene dates of 62.5±2.2 Ma and 42.1±2.9 Ma are associated with two igneous episodes prior to opening of South China Sea basin. Those pre-Paleocene zircons are inherited zircons mostly with magmatogenic oscillatory zones, and have REE features of crustal zircon. Zircon U-Pb dates of 2518-2481 Ma, 1933- 1724 Ma, and 1094-1040 Ma from the SCSV1 volcanics, and 2810-2718 Ma, 2458-2421 Ma, and 1850-993.4 Ma from the SCSV2 volcanics reveal part of Precambrian evolution of the northern South China Sea, well comparable with age records dated from the Cathaysia block. The data of 927.0±6.9 Ma and 781±38 Ma dated from the SCSV2 coincide with amalgamation between Yangtze and Cathaysia blocks and breakup of the Rodinia, respectively. The age records of Caledonian orogeny from the Cathaysia block are widely found from our volcanic samples with concordant mean ages of 432.0±5.8 Ma from the SCSV1 and of 437±15 Ma from the SCSV2. The part of the northern South China Sea resembling the Cathaysia underwent Indosinian and Yanshannian tectonothermal events. Their age signatures from the SCSV1 cover 266.5±3.5 Ma, 241.1±6.0 Ma, 184.0±4.2 Ma, 160.9±4.2 Ma and 102.8±2.6 Ma, and from the SCSV2 are 244±15 Ma, 158.1±3.5 Ma, 141±13 Ma and 96.3±2.1 Ma. Our pre-Paleogene U-Pb age spectra of zircons from the borehole volcanics indicate that the northern South China Sea underwent an evolution from formation of Precambrian basement, Caledonian orogeny, and Indosinian orogeny to Yanshannian magmatism. This process can be well comparable with the tectonic evolution of South China, largely supporting the areas of the northern South China Sea as part of southward extension of the展开更多
Recent research results showed that the Cathaysia flora originated and developed from the global uniform Lepidodendropsis flora of the Early Carboniferous, which had already become an independent flora in the early La...Recent research results showed that the Cathaysia flora originated and developed from the global uniform Lepidodendropsis flora of the Early Carboniferous, which had already become an independent flora in the early Late Carboniferous (Namurian B to C). The center of origin of the Cathaysia flora is restricted to the North China Plate. On the basis of the successional characteristics of the Cathaysia flora in different geological ages, it may be divided into seven evolutionary stages. The evolutionary trend of the Cathaysia flora, as a whole, was characterized by the gradual increase of the typical Cathaysian elements in the sequence from the early Late Carboniferous to the early Late Permian, which began to decline during the late Late Permian. The climatic differentiation, tectonic movement,oceanic circulation, palaeogeographical environment, extraterrestrial event and plant evolution caused the mass extinction of the Cathaysia flora on a large scale by the end of the Permian.展开更多
This paper reports the geochemical and zircon U-Pb dating data of the Sinian to Cambrian low-grade metamorphic rocks in the Miaoer Mountain area,Guangxi and the Jinjiling area,Hunan Province.Petrographic and geochemic...This paper reports the geochemical and zircon U-Pb dating data of the Sinian to Cambrian low-grade metamorphic rocks in the Miaoer Mountain area,Guangxi and the Jinjiling area,Hunan Province.Petrographic and geochemical features indicate that protoliths of these metamorphic rocks are clastic sedimentary rocks with medium weathering,which were formed in the passive continental margin.Geochemistry and zircon U-Pb ages indicate that the Sinian and Cambrian sedimentary rocks in the Jinjiling area have similar detritus components,which are characterized by abundant Grenvillian detrital zircons,suggesting a close affinity with the Cathaysia Block.The Cambrian sedimentary rocks in the Miaoer Mountain area have similar geochemistry and zircon geochronology to those in the Jinjiling area,showing an affinity with the Cathaysia Block.However,the Sinian sedimentary rocks in the Miaoer Mountain area show different geochemical features from the Cambrian sedimentary rocks and those in the Jinjiling area,and are characterized by abundant 840–700 Ma detrital zircons and less^2.0 Ga ones,showing a close affinity with the Yangtze Block.These variations suggest that the Jinjiling area continuously accepted the fragments from the Cathaysia from the Sinian to the Cambrian,whereas the provenance of the Miaoer Mountain sedimentary basin changed from the Yangtze Block to the Cathaysia Block during this interval.This change implies a tectonic movement,which caused the further sinking of the basin in the Miaoer Mountain area and northwestward transferring of the basin center before the Middle Cambrian,so that the Miaoer Mountain basin received the detritus from the Cathaysia Block in the Middle Cambrian.This fact also proves that the Yangtze and Cathaysia blocks have converged at least in Middle Cambrian,and the southwestern boundary between them is located between the Miaoer Mountain and Jinjiling areas.展开更多
The Dajiangbian Formation in South China is a siliciclastic-dominated sedimentary succession with low-grade metamorphism deposited on the western margin of the Cathaysia Block, and is capped by a glaciogenic diamictit...The Dajiangbian Formation in South China is a siliciclastic-dominated sedimentary succession with low-grade metamorphism deposited on the western margin of the Cathaysia Block, and is capped by a glaciogenic diamictite（the Sizhoushan Formation）. The Sizhoushan glaciogenic strata can be attributed to the Jiangkou glacial（Sturtian glacial） episode as they share stratigraphic and lithological similarities with Jiangkou strata in South China. Some carbonate, chert and shale units throughout the upper part of the Dajiangbian Formation were sampled for carbonate carbon isotope（δ^（13）C_（carb）） and organic carbon isotope（δ^（13）C_（org）） analyses. A range of geochemical indices including oxygen isotopes（δ^（18）O） and Mn/Sr（Fe/Sr） ratios suggest that primary carbon isotope values were preserved in the upper Dajiangbian Formation. The upper Dajiangbian Formation shows δ^（13）C_（carb） of-0.1‰, upward decreasing towards to-5.4‰. We suggest that the negative δ^（13）C excursion beneath the Sizhoushan diamictite is correlative with the Pre-Sturtian Islay δ^（13）C_（carb） anomaly and allows correlation with the global Neoproterozoic isotope stratigraphy. We find that carbonate and organic carbon isotope data of the upper Dajiangbian Formation are coupled, consistent with the δ^（13）C_（carb）-δ^（13）C_（org） pattern observed on multiple continents.展开更多
The Ediacaran and early Cambrian black shales are widespread across the South China Craton （Yangtze and Cathaysia blocks）. However, the trace element distribution patterns of the Ediacaran and early Cambrian black s...The Ediacaran and early Cambrian black shales are widespread across the South China Craton （Yangtze and Cathaysia blocks）. However, the trace element distribution patterns of the Ediacaran and early Cambrian black shales in the Cathaysia Block are still unclear. In this study, thirty- four black shale samples in the Lechangxia Group （Ediacaran） and thirteen black shale samples in the lower Bacun Group （early Cambrian） from Guangning area, western Guangdong Province, South China, were analyzed for major and trace elements concentrations. Compared to the upper continental crust, the Ediacaran black shales exhibit strongly enriched Se, Ga, and As with enrichment factor values （EF） higher than 10, significantly enrichedBi and Rb （10〉EF〉5）, weakly enriched Mo, Ba, Cs, V, In, Be, TI, and Th （5〉EF〉2）, normal U, Cr, Cd, Sc, Pb, Cu, and Li （2〉EF〉0.5）, and depleted Ni, Zn, Sr, and Co. Early Cambrian black shales display strongly enriched Se, Ga, and As, significantly enriched Ba, Bi, and Rb, weakly enriched Mo, Cs, Cd, V, U, Be, In, and TI, normal Sc, Th, Cr, Li, Cu, Ni, and Pb and depleted Co, Zn, and Sr. Moreover, Se is the most enriched trace element in the Ediacaran and early Cambrian black shales： concentrations vary from 0.25 to 30.09 ppm and 0.54 to 5.01 ppm, and averaging 4.84 and 1.72 ppm, with average EF values of 96.87 and 34.32, for the Ediacaran and early Cambrian shales respectively. The average concentration of Se in the Ediacaran black shales is 2.8 times higher than that of early Cambrian black shales. Se contents in the Ediacaran and early Cambrian black shales exhibit significant variation （P = 0.03）. Provenance analysis showed that Se contents of both the Ediacaran and early Cambrian black shales were without detrital provenance and volcanoclastic sources, hut of hydrothermal origin. The deep sources of Se and the presence of pyrite may explain the higher Se contents in the Ediacaran black shales. Similar with the Se-rich characteristics of the contemporaneo展开更多
基金funded by the Nonprofit Special Research Program"The formation and destruction of northeastern segment of Cathaysia-the Yangtze Plate Suture Zone and their mineralization"(No.200811015)from the Ministry of Land and Resourcethe Land Resource Survey Project of the Ministry of Land and Natural Resources,China"The convergence and breakup process of main blocks of China and their geological background for mineralization"(Nos.1212011121064,1212011121068)from the China Geological Survey
文摘Multistage deformation events have occurred in the northeastern Jiangshao Fault （Suture） Belt. The earliest two are ductile deformation events. The first is the ca. 820 Ma top-to-the-northwest ductile thrusting, which directly resulted from the collision between the Cathaysia Old Land and the Chencai Arc （？） during the Late Neoproterozoic, and the Jiangnan Orogenic Belt that formed as the ocean closed between the Yangtze Plate and the jointed Cathaysia Old Land and the Chencai Arc due to continuous compression. The second is the ductile left-lateral strike-slipping that occurred in the latest Early Paleozoic. Since the Jinning period, all deformation events represent the reactivation or inversion of intraplate structures due to the collisions between the North China and Yangtze plates during the Triassic and between the Philippine Sea and Eurasian plates during the Cenozoic. In the Triassic, brittle right-lateral strike-slipping and subsequent top-to-the south thrusting occurred along the whole northeastern Jiangshao Fault Zone because of the collision between the North China and Yangtze plates. In the Late Mesozoic, regional extension took place across southeastern China. In the Cenozoic, the collision between the Philippine Sea and Eurasian plates resulted in brittle thrusts along the whole Jiangnan Old land in the Miocene. The Jiangshao Fault Belt is a weak zone in the crust with long history, and its reactivation is one of important characteristics of the deformation in South China; however, late-stage deformation events did not occur beyond the Jiangnan Old Land and most of them are parallel to the strike of the Old Land, which is similar to the Cenozoic deformation in Central Asia. In addition, the Jiangnan old Land is not a collisional boundary between the Yangtze Plate and Cathaysia Old Land in the Triassic.
文摘The Cathaysla flora, one of the most prominent floras of the Carboniferous and Permian, was mainly distributed In East Asia and was characterized by numerous endemic elements. China Is one of the most Important localities of the Cathaysla flora and It ;s also the center of origin of this flora. This paper reviews and discusses the characteristics of the Cathaysla flora and the blogeographlcally mixed Permian Cathayslan-Angaran floras of East Asia. In addition, the formative mechanism of the mixed Permian floras Is also discussed.
基金jointly supported by the National Natural Science Foundation of China (No.41102131)the Fundamental Research Funds for the Central Universities of China (No.12lgpy22)+3 种基金Guangdong Natural Science Foundation (No.2015A030313193)China Geological Survey (No.1212011121064)Chinese Association for science and technology project (No.2014XSJLW01-02)China Scholarship Council
文摘The Eastern Guangxi area locates in the southwestern part of the transition zone between Yangtze and Cathaysia blocks, which is an important region because the boundary between two blocks probablycrosses there. We determined LA-ICPMS U-Pb ages for detrital zircons extracted from three sandstone samples in the Sinian-Cambrian strata in this region. The resulting ages are in the range of the Archeozoic and Neoproterozoic, with three notable concentrates at 991 Ma, 974 Ma, and 964 Ma, all of which are coeval to the Grenvillian magmatic activity. The new age distribution is similar to the data reported in the Precambrian strata of the adjacent southwestern Cathaysia Block, suggesting that most of our detrital zircons are likely derived from the Cathaysia Block. Combined with others＇ research, we are more inclined to accept the opinion that there was not an ocean basin between the two blocks during the Sinian-Cambrian period in Eastern Guangxi area if the timing of collision is the Early Neoproterzoic. But if the timing of collision is the Early Paleozoic, we conclude that Luzhai uplift（i.e., the uplift between Guilin-Yongfu faultand Lipu fault） beyond the west of Dayaoshan regoin might be one part of southwestern sedimentation boundary of Cathaysia Block and Yangtze Block. We also get a few of detrital zircons with ages of ~590 Ma which probably sourced from northeastern Gondwana and 13 detrital zircons with over 3 000 Ma U-Pb ages which record the early formation of the earth.
基金supported by the National Natural Science Foundation of China (grant no. 41272218)the Fundamental Research Funds for the Central Universitiesthe State Key Program of the National Natural Science of China (grant no. 2011ZX05023-003)
文摘Five Paleogene volcanics sampled from the northern South China Sea were analyzed via LA-ICP-MS zircon U-Pb dating, including basalt and andesite from Borehole SCSVI and volcanic agglomerate from Borehole SCSV2, respectively. A total of 162 zircon U-Pb dates for them cover an age range from Neoarchean to Eocene, in which the pre-Paleocene data dominate. The Paleogene dates of 62.5±2.2 Ma and 42.1±2.9 Ma are associated with two igneous episodes prior to opening of South China Sea basin. Those pre-Paleocene zircons are inherited zircons mostly with magmatogenic oscillatory zones, and have REE features of crustal zircon. Zircon U-Pb dates of 2518-2481 Ma, 1933- 1724 Ma, and 1094-1040 Ma from the SCSV1 volcanics, and 2810-2718 Ma, 2458-2421 Ma, and 1850-993.4 Ma from the SCSV2 volcanics reveal part of Precambrian evolution of the northern South China Sea, well comparable with age records dated from the Cathaysia block. The data of 927.0±6.9 Ma and 781±38 Ma dated from the SCSV2 coincide with amalgamation between Yangtze and Cathaysia blocks and breakup of the Rodinia, respectively. The age records of Caledonian orogeny from the Cathaysia block are widely found from our volcanic samples with concordant mean ages of 432.0±5.8 Ma from the SCSV1 and of 437±15 Ma from the SCSV2. The part of the northern South China Sea resembling the Cathaysia underwent Indosinian and Yanshannian tectonothermal events. Their age signatures from the SCSV1 cover 266.5±3.5 Ma, 241.1±6.0 Ma, 184.0±4.2 Ma, 160.9±4.2 Ma and 102.8±2.6 Ma, and from the SCSV2 are 244±15 Ma, 158.1±3.5 Ma, 141±13 Ma and 96.3±2.1 Ma. Our pre-Paleogene U-Pb age spectra of zircons from the borehole volcanics indicate that the northern South China Sea underwent an evolution from formation of Precambrian basement, Caledonian orogeny, and Indosinian orogeny to Yanshannian magmatism. This process can be well comparable with the tectonic evolution of South China, largely supporting the areas of the northern South China Sea as part of southward extension of the
文摘Recent research results showed that the Cathaysia flora originated and developed from the global uniform Lepidodendropsis flora of the Early Carboniferous, which had already become an independent flora in the early Late Carboniferous (Namurian B to C). The center of origin of the Cathaysia flora is restricted to the North China Plate. On the basis of the successional characteristics of the Cathaysia flora in different geological ages, it may be divided into seven evolutionary stages. The evolutionary trend of the Cathaysia flora, as a whole, was characterized by the gradual increase of the typical Cathaysian elements in the sequence from the early Late Carboniferous to the early Late Permian, which began to decline during the late Late Permian. The climatic differentiation, tectonic movement,oceanic circulation, palaeogeographical environment, extraterrestrial event and plant evolution caused the mass extinction of the Cathaysia flora on a large scale by the end of the Permian.
基金supported by the National Natural Science Foundation of China(Grant No.41272085)research grants from the Bureau of Nuclear Geology of China(YK11)+1 种基金the Major State Basic Research Program(Grant No.2012CB416701)the State Key Laboratory for Mineral Deposits Research(Nanjing University)(Grant No.ZZKT-201106)
文摘This paper reports the geochemical and zircon U-Pb dating data of the Sinian to Cambrian low-grade metamorphic rocks in the Miaoer Mountain area,Guangxi and the Jinjiling area,Hunan Province.Petrographic and geochemical features indicate that protoliths of these metamorphic rocks are clastic sedimentary rocks with medium weathering,which were formed in the passive continental margin.Geochemistry and zircon U-Pb ages indicate that the Sinian and Cambrian sedimentary rocks in the Jinjiling area have similar detritus components,which are characterized by abundant Grenvillian detrital zircons,suggesting a close affinity with the Cathaysia Block.The Cambrian sedimentary rocks in the Miaoer Mountain area have similar geochemistry and zircon geochronology to those in the Jinjiling area,showing an affinity with the Cathaysia Block.However,the Sinian sedimentary rocks in the Miaoer Mountain area show different geochemical features from the Cambrian sedimentary rocks and those in the Jinjiling area,and are characterized by abundant 840–700 Ma detrital zircons and less^2.0 Ga ones,showing a close affinity with the Yangtze Block.These variations suggest that the Jinjiling area continuously accepted the fragments from the Cathaysia from the Sinian to the Cambrian,whereas the provenance of the Miaoer Mountain sedimentary basin changed from the Yangtze Block to the Cathaysia Block during this interval.This change implies a tectonic movement,which caused the further sinking of the basin in the Miaoer Mountain area and northwestward transferring of the basin center before the Middle Cambrian,so that the Miaoer Mountain basin received the detritus from the Cathaysia Block in the Middle Cambrian.This fact also proves that the Yangtze and Cathaysia blocks have converged at least in Middle Cambrian,and the southwestern boundary between them is located between the Miaoer Mountain and Jinjiling areas.
基金supported by the Chinese National "973" Project (No. 2013CB835005) to X. H. Li(Nos. 40603021, 41072145) to L. F.
文摘The Dajiangbian Formation in South China is a siliciclastic-dominated sedimentary succession with low-grade metamorphism deposited on the western margin of the Cathaysia Block, and is capped by a glaciogenic diamictite（the Sizhoushan Formation）. The Sizhoushan glaciogenic strata can be attributed to the Jiangkou glacial（Sturtian glacial） episode as they share stratigraphic and lithological similarities with Jiangkou strata in South China. Some carbonate, chert and shale units throughout the upper part of the Dajiangbian Formation were sampled for carbonate carbon isotope（δ^（13）C_（carb）） and organic carbon isotope（δ^（13）C_（org）） analyses. A range of geochemical indices including oxygen isotopes（δ^（18）O） and Mn/Sr（Fe/Sr） ratios suggest that primary carbon isotope values were preserved in the upper Dajiangbian Formation. The upper Dajiangbian Formation shows δ^（13）C_（carb） of-0.1‰, upward decreasing towards to-5.4‰. We suggest that the negative δ^（13）C excursion beneath the Sizhoushan diamictite is correlative with the Pre-Sturtian Islay δ^（13）C_（carb） anomaly and allows correlation with the global Neoproterozoic isotope stratigraphy. We find that carbonate and organic carbon isotope data of the upper Dajiangbian Formation are coupled, consistent with the δ^（13）C_（carb）-δ^（13）C_（org） pattern observed on multiple continents.
基金the National Natural Science Foundation of China (Grant No.41172310, 41472322 and 40872210)the National Basic Research Program of China (Grant No.2014CB238906)the Local Science and Technology Tasks "Distribution Patterns and Prospect of Exploitation and Utilization of Selenium in Foshan area, Guangdong" and "Construction for Laboratory of Selenium Resources Comprehensive Utilization"
文摘The Ediacaran and early Cambrian black shales are widespread across the South China Craton （Yangtze and Cathaysia blocks）. However, the trace element distribution patterns of the Ediacaran and early Cambrian black shales in the Cathaysia Block are still unclear. In this study, thirty- four black shale samples in the Lechangxia Group （Ediacaran） and thirteen black shale samples in the lower Bacun Group （early Cambrian） from Guangning area, western Guangdong Province, South China, were analyzed for major and trace elements concentrations. Compared to the upper continental crust, the Ediacaran black shales exhibit strongly enriched Se, Ga, and As with enrichment factor values （EF） higher than 10, significantly enrichedBi and Rb （10〉EF〉5）, weakly enriched Mo, Ba, Cs, V, In, Be, TI, and Th （5〉EF〉2）, normal U, Cr, Cd, Sc, Pb, Cu, and Li （2〉EF〉0.5）, and depleted Ni, Zn, Sr, and Co. Early Cambrian black shales display strongly enriched Se, Ga, and As, significantly enriched Ba, Bi, and Rb, weakly enriched Mo, Cs, Cd, V, U, Be, In, and TI, normal Sc, Th, Cr, Li, Cu, Ni, and Pb and depleted Co, Zn, and Sr. Moreover, Se is the most enriched trace element in the Ediacaran and early Cambrian black shales： concentrations vary from 0.25 to 30.09 ppm and 0.54 to 5.01 ppm, and averaging 4.84 and 1.72 ppm, with average EF values of 96.87 and 34.32, for the Ediacaran and early Cambrian shales respectively. The average concentration of Se in the Ediacaran black shales is 2.8 times higher than that of early Cambrian black shales. Se contents in the Ediacaran and early Cambrian black shales exhibit significant variation （P = 0.03）. Provenance analysis showed that Se contents of both the Ediacaran and early Cambrian black shales were without detrital provenance and volcanoclastic sources, hut of hydrothermal origin. The deep sources of Se and the presence of pyrite may explain the higher Se contents in the Ediacaran black shales. Similar with the Se-rich characteristics of the contemporaneo
