Both gradual and sharp decrease in organic and carbonate carbon isotope values were detected across the Permian-Triassic boundary in the Meishan section, Changxing, Zhejiang Province, China. The gradual decrease in or...Both gradual and sharp decrease in organic and carbonate carbon isotope values were detected across the Permian-Triassic boundary in the Meishan section, Changxing, Zhejiang Province, China. The gradual decrease in organic carbon isotope values started at the bottom of Bed 23, coinciding with the strong oscillations of total organic carbon (TOC) contents, indicates increasing fluxes from carbonate to organic carbon reservoir during this interval. A 2.3‰ sharp drop of inorganic carbon isotope values occurred at the uppermost part of Bed 24e. A 3.7‰ sharp drop of organic carbon isotope values occurred in Bed 26. The dramatic drop of inorganic carbon isotope value of 8‰ reported previously is not confirmed from the unweathered carbonate samples in Bed 27. The large-scale fluctuation of organic carbon isotope values in the Yinkeng Formation reflects different extent of mixing of marine and terrestrial organic matters. The gradual depletion and subsequent sharp drop of carbon isotopes near the展开更多
In this paper, we consider a bisexual Galton-Watson branching process whose offspring probability distribution is controlled by a random environment proccss. Some results for the probability generating functions assoc...In this paper, we consider a bisexual Galton-Watson branching process whose offspring probability distribution is controlled by a random environment proccss. Some results for the probability generating functions associated with the process are obtained and sufficient conditions for certain extinction and for non-certain extinction are established.展开更多
This paper reports a Lower Triassic inorganic carbon isotope profile from the North Pingdingshan Section in Chaohu, Anhui Province, China, which was situated in a deep part of the Lower Yangtze carbonate ramp. The ...This paper reports a Lower Triassic inorganic carbon isotope profile from the North Pingdingshan Section in Chaohu, Anhui Province, China, which was situated in a deep part of the Lower Yangtze carbonate ramp. The δ ( 13 C) excursion shows two periods from the Permian Triassic boundary to the lower Spathian substage, corresponding to the ecosystem undergoing evolution and recovery after the end Permian mass extinction and related events. The first period starts at the δ ( 13 C) depletion caused by the mass extinction and evolves with a gradual δ ( 13 C) increase resulting from the development of some disaster taxa during the Induan. The strong Smithian δ ( 13 C) depletion in the second period might be formed by the collapse of the disaster ecosystem and the biotic recovery occurred with the explosive increase of bioproductivity in the Spathian. Thus the δ ( 13 C) excursion in the Lower Triassic expresses patterns of biotic evolution and recovery during the erratic ecosystem that followed the great end Permian mass extinction.展开更多
To better understand the potential causes of visibility impairment in autumn and winter in Chengdu,relative humidity(RH),visibility,the concentrations of PM2.5 and its chemical components were on-line measured continu...To better understand the potential causes of visibility impairment in autumn and winter in Chengdu,relative humidity(RH),visibility,the concentrations of PM2.5 and its chemical components were on-line measured continuously in Chengdu from Nov.2016 to Jan.2017.Six obvious haze episodes occurred in Chengdu,with the total time of haze episodes accounted for more than 90%of the total observation period,and higher NO2 concentrations and RH were related to the high particle concentrations in haze episodes.The visibility decreased in a non-linear tendency under different RH conditions with the increase of PM2.5 concentrations,which was more sensitive to RH under lower PM2.5 concentrations.The threshold concentration of PM2.5 got more smaller with the increase of RH.During the entire observation period,organic matter(OM)was the largest contributor(31.12%to extinction coefficient(bext)),followed by NH4NO3 and(NH4)2SO4 with 28.03%and 23.01%,respectively.However,with the visibility impairment from Type I(visibility>10 km)to Type IV(visibility≤2 km),the contribution of OM to bextdecreased from 38.12%to 26.77%,while the contribution of NH4NO3 and(NH4)2SO4 to bextincreased from 19.09%and 20.20%to 34.29%and 24.35%,respectively,and NH4NO3 became the largest contributor to bextat Type IV.The results showed that OM and NH4NO3 were the key components of PM2.5 for visibility impairment in Chengdu,indicating that the control of precursors emissions of carbonaceous species and NH4NO3 could effectively improve the visibility in Chengdu.展开更多
In this work, a one-year observation focusing on high time resolution characteristics of components in fine particles was conducted at an urban site in Shanghai. Contributions of different components on visibility imp...In this work, a one-year observation focusing on high time resolution characteristics of components in fine particles was conducted at an urban site in Shanghai. Contributions of different components on visibility impairment were also studied. Our research indicates that the major components of PM2.5 in Shanghai are water-soluble inorganic ions and carbonaceous aerosol, accounting for about 60% and 30% respectively. Higher concentrations of sulfate （SO42-） and organic carbon （OC） in PM2.s occurred in fall and summer, while higher concentrations of nitrate （NO3-） were observed in winter and spring. The mass concentrations of Cl- and K＋ were higher in winter. Moreover, NO3- increased significantly during PM2.s pollution episodes. The high values observed for the sulfate oxidizing rate （SOR）, nitrate oxidizing rate （NOR） and secondary organic carbon （SOC） in OC indicate that photochemical reactions were quite active in Shanghai. The IMPROVE （Interagency Monitoring of Protected Visual Environments） formula was used in this study to investigate the contributions of individual PM2.5 chemical components to the light extinction efficient in Shanghai. Both NH4NO3 and （NH4）aSO4 had close relationships with visibility impairment in Shanghai. Our results show that the reduction of anthropogenic SO2, NOx and NH3 would have a significant effect on the improvement of air qualitv and visibility in Shanghai.展开更多
The event Permian-Triassic boundary (EPTB) is well marked by the famous 'white clay' of bed 25 in Mei-shan Section located in Changxing county, Zhejiang province of China. In this note, the white clay as well ...The event Permian-Triassic boundary (EPTB) is well marked by the famous 'white clay' of bed 25 in Mei-shan Section located in Changxing county, Zhejiang province of China. In this note, the white clay as well as its overlying and underlying sequences is investigated particularly for mineralogical records. The investigation yields three findings that contribute to better understanding the scenario of the EPTB mass extinction. (i) A red goethite-rich microlayer (0.3 mm) is first recognized to be horizontally widespread on the base of the white clay in the section. The microlayer should be considered as a macro geochemical indicator naturally tracing a catastrophic initiation at the EPTB. (ii) An interruption of marine carbonate deposition is discovered due to blank of carbonate minerals in the white clay. The discovery provides significant evidence of a marine acidification event that would occur in the paleo-ocean with marine acidity estimated at pH【4.0 at least and be triggered by the ultimate展开更多
The widespread microbialites deposition that followed the End-Permian mass extinction in the Tethyan realm have been intensively studied because of the evidence they provide on the nature of this crisis and its afterm...The widespread microbialites deposition that followed the End-Permian mass extinction in the Tethyan realm have been intensively studied because of the evidence they provide on the nature of this crisis and its aftermath. However, the age of the microbialite event remains controversial. New conodont collection across the Permian–Triassic（P–T） transition from Dajiang（Guizhou Province, South China） in this study enable us to discriminate four conodont zones, in ascending order, they are： Hindeodus parvus zone, Isarcicella lobata zone, Isarcicella isarcica zone and Hindeodus sosioensis zone. The age of microbialite in the P–T transition at the Dajiang Section is considered to be within the Hindeodus parvus zone and thus to clearly post-date the main extinction crisis. Reviewing the age of onset of microbialites throughout the Tethyan regions reveals two different ages： a Hindeodus changxingensis zone age is dominant in south-western and westernmost Tethys, whilst most other regions show microbialite deposition began in the Hindeodus parvus zone. Our investigation also indicates that two conodont changes occur at this time： an increase of hindeodid species immediately following a sequence boundary and the mass extinction, and a phase of extinction losses in the earliest Triassic Isarcicella isarcica zone during highstand development.展开更多
The greatest Phanerozoic mass extinction happened at the end-Permian to earliest Triassic. About 95% species, 82% genera, and more than half families became extinct, constituting the sole macro-mass extinction in geol...The greatest Phanerozoic mass extinction happened at the end-Permian to earliest Triassic. About 95% species, 82% genera, and more than half families became extinct, constituting the sole macro-mass extinction in geological history. This event not only caused the great extinction but also destroyed the 200 Myr-long Paleozoic marine ecosystem, prompted its transition to Mesozoic ecosystem, and induced coal gap on land as well as reef gap and chert gap in ocean. The biotic crisis during the Paleozoic-Mesozoic transition was a long process of co-evolution between geospheres and biosphere. The event sequence at the Permian-Triassic boundary （PTB） reveals two-episodic pattern of rapidly deteriorating global changes and biotic mass ex- tinction and the intimate relationship between them. The severe global changes coupling multiple geospheres may have affect- ed the Pangea integration on the Earth＇s surface spheres, which include： the Pangea integration→enhanced mountain height and basin depth, changes of wind and ocean current systems; enhanced ocean basin depth→the greatest Phanerozoic regression at PTB, disappearance of epeiric seas and subsequent rapid transgression; the Pangea integration→thermal isolation effect of continental lithosphere and decrease of mid-ocean ridges→development of continental volcanism; two-episode volcanism causing LIPs of the Emeishan Basalt and the Siberian Trap （25%251 Ma）→global warming and mass extinction; continental aridification and replacement of monsoon system by latitudinal wind system→destruction of vegetation; enhanced weathering and CH4 emission→negative excursion of δ^13C; mantle plume→crust doming→regression; possible relation between the Illawarra magnetic reversal and the PTB extinction, and so on. Mantle plume produced the Late Permian LIPs and mantle convection may have caused the process of the Pangea integration. Subduction, delamination, and accumulation of the earth＇s cool lithospheric material at the ＂D＂ layer of CMB started mantl展开更多
The objective of this study was to reconstruct light extinction coefficients （b ext ） according to chemical composition components of particulate matter up to 2.5 μm in size （PM 2.5 ）. PM 2.5 samples were collect...The objective of this study was to reconstruct light extinction coefficients （b ext ） according to chemical composition components of particulate matter up to 2.5 μm in size （PM 2.5 ）. PM 2.5 samples were collected at the monitoring station of the South China of Institute of Environmental Science （SCIES, Guangzhou, China） during January 2010, and the online absorbing and scattering coefficients were obtained using an aethalometer and a nephelometer. The measured values of light absorption coefficient by particle （b ap ） and light scattering coefficient by particle （b sp ） significantly correlated （R 2 0.95） with values of b ap and b sp that were reconstructed using the Interagency Monitoring of Protected Visual Environments （IMPROVE） formula when RH was 70%. The measured b ext had a good correlation （R 2 0.83） with the calculated b ext under ambient RH conditions. The result of source apportionment of b ext showed that ammonium sulfate [（NH 4 ） 2 SO 4 ] was the largest contributor （35.0%） to b ext , followed by ammonium nitrate （NH 4 NO 3 , 22.9%）, organic matter （16.1%）, elemental carbon （11.8%）, sea salt （4.7%）, and nitrogen dioxide （NO 2 , 9.6%）. To improve visibility in Guangzhou, the effective control of secondary particles like sulfates, nitrates, and ammonia should be given more attention in urban environmental management.展开更多
基金This work was supported by the Major Basic Research Projects of the Ministry of Science Technology of China (Grant No. G2000077700) Opening Laboratory of Palaeobiology and Stratigraphy of Nanjing Institute of Geology and Palaeontology, the Chinese
文摘Both gradual and sharp decrease in organic and carbonate carbon isotope values were detected across the Permian-Triassic boundary in the Meishan section, Changxing, Zhejiang Province, China. The gradual decrease in organic carbon isotope values started at the bottom of Bed 23, coinciding with the strong oscillations of total organic carbon (TOC) contents, indicates increasing fluxes from carbonate to organic carbon reservoir during this interval. A 2.3‰ sharp drop of inorganic carbon isotope values occurred at the uppermost part of Bed 24e. A 3.7‰ sharp drop of organic carbon isotope values occurred in Bed 26. The dramatic drop of inorganic carbon isotope value of 8‰ reported previously is not confirmed from the unweathered carbonate samples in Bed 27. The large-scale fluctuation of organic carbon isotope values in the Yinkeng Formation reflects different extent of mixing of marine and terrestrial organic matters. The gradual depletion and subsequent sharp drop of carbon isotopes near the
文摘In this paper, we consider a bisexual Galton-Watson branching process whose offspring probability distribution is controlled by a random environment proccss. Some results for the probability generating functions associated with the process are obtained and sufficient conditions for certain extinction and for non-certain extinction are established.
基金ThisresearchissupportedbytheChinese" 973Program" (No .G2 0 0 0 0 7770 5 ) theNationalNaturalScienceFoundationofChina (No .40 0 72 0 11) theChinaNationalCommissiononStratigraphyandtheYichangCenterofStratigraphyandPaleontology .
文摘This paper reports a Lower Triassic inorganic carbon isotope profile from the North Pingdingshan Section in Chaohu, Anhui Province, China, which was situated in a deep part of the Lower Yangtze carbonate ramp. The δ ( 13 C) excursion shows two periods from the Permian Triassic boundary to the lower Spathian substage, corresponding to the ecosystem undergoing evolution and recovery after the end Permian mass extinction and related events. The first period starts at the δ ( 13 C) depletion caused by the mass extinction and evolves with a gradual δ ( 13 C) increase resulting from the development of some disaster taxa during the Induan. The strong Smithian δ ( 13 C) depletion in the second period might be formed by the collapse of the disaster ecosystem and the biotic recovery occurred with the explosive increase of bioproductivity in the Spathian. Thus the δ ( 13 C) excursion in the Lower Triassic expresses patterns of biotic evolution and recovery during the erratic ecosystem that followed the great end Permian mass extinction.
基金supported by Sichuan Science and Technology Program (Nos. 2018SZ0316, 2018SZDZX0023)the Research on Forecasting Technology of Heavy Pollution Weather
文摘To better understand the potential causes of visibility impairment in autumn and winter in Chengdu,relative humidity(RH),visibility,the concentrations of PM2.5 and its chemical components were on-line measured continuously in Chengdu from Nov.2016 to Jan.2017.Six obvious haze episodes occurred in Chengdu,with the total time of haze episodes accounted for more than 90%of the total observation period,and higher NO2 concentrations and RH were related to the high particle concentrations in haze episodes.The visibility decreased in a non-linear tendency under different RH conditions with the increase of PM2.5 concentrations,which was more sensitive to RH under lower PM2.5 concentrations.The threshold concentration of PM2.5 got more smaller with the increase of RH.During the entire observation period,organic matter(OM)was the largest contributor(31.12%to extinction coefficient(bext)),followed by NH4NO3 and(NH4)2SO4 with 28.03%and 23.01%,respectively.However,with the visibility impairment from Type I(visibility>10 km)to Type IV(visibility≤2 km),the contribution of OM to bextdecreased from 38.12%to 26.77%,while the contribution of NH4NO3 and(NH4)2SO4 to bextincreased from 19.09%and 20.20%to 34.29%and 24.35%,respectively,and NH4NO3 became the largest contributor to bextat Type IV.The results showed that OM and NH4NO3 were the key components of PM2.5 for visibility impairment in Chengdu,indicating that the control of precursors emissions of carbonaceous species and NH4NO3 could effectively improve the visibility in Chengdu.
基金supported by the “Chinese National Key Technology R&D Program” (No. 2014BAC22B03)the “Chinese National Non-profit Scientific Research Program” (No. 201409008)the Key Research Project from the Science and Technology Commission of Shanghai Municipality Fund Project (No. 14DZ1202905)
文摘In this work, a one-year observation focusing on high time resolution characteristics of components in fine particles was conducted at an urban site in Shanghai. Contributions of different components on visibility impairment were also studied. Our research indicates that the major components of PM2.5 in Shanghai are water-soluble inorganic ions and carbonaceous aerosol, accounting for about 60% and 30% respectively. Higher concentrations of sulfate （SO42-） and organic carbon （OC） in PM2.s occurred in fall and summer, while higher concentrations of nitrate （NO3-） were observed in winter and spring. The mass concentrations of Cl- and K＋ were higher in winter. Moreover, NO3- increased significantly during PM2.s pollution episodes. The high values observed for the sulfate oxidizing rate （SOR）, nitrate oxidizing rate （NOR） and secondary organic carbon （SOC） in OC indicate that photochemical reactions were quite active in Shanghai. The IMPROVE （Interagency Monitoring of Protected Visual Environments） formula was used in this study to investigate the contributions of individual PM2.5 chemical components to the light extinction efficient in Shanghai. Both NH4NO3 and （NH4）aSO4 had close relationships with visibility impairment in Shanghai. Our results show that the reduction of anthropogenic SO2, NOx and NH3 would have a significant effect on the improvement of air qualitv and visibility in Shanghai.
基金This work was partly supported by the National Natural Science Foundation of China (Grant Nos. 40072055 and 40043010).
文摘The event Permian-Triassic boundary (EPTB) is well marked by the famous 'white clay' of bed 25 in Mei-shan Section located in Changxing county, Zhejiang province of China. In this note, the white clay as well as its overlying and underlying sequences is investigated particularly for mineralogical records. The investigation yields three findings that contribute to better understanding the scenario of the EPTB mass extinction. (i) A red goethite-rich microlayer (0.3 mm) is first recognized to be horizontally widespread on the base of the white clay in the section. The microlayer should be considered as a macro geochemical indicator naturally tracing a catastrophic initiation at the EPTB. (ii) An interruption of marine carbonate deposition is discovered due to blank of carbonate minerals in the white clay. The discovery provides significant evidence of a marine acidification event that would occur in the paleo-ocean with marine acidity estimated at pH【4.0 at least and be triggered by the ultimate
基金supported by the Natural Science Foundation of China (Nos. 41172024, 41272044)the "973" Program (No. 2011CB808800)+2 种基金the "111" Project (No. B08030)the ‘Fundamental Research Funds for the Central Universities,China University of Geosciences (Wuhan)the State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences (No. GBL11202)
文摘The widespread microbialites deposition that followed the End-Permian mass extinction in the Tethyan realm have been intensively studied because of the evidence they provide on the nature of this crisis and its aftermath. However, the age of the microbialite event remains controversial. New conodont collection across the Permian–Triassic（P–T） transition from Dajiang（Guizhou Province, South China） in this study enable us to discriminate four conodont zones, in ascending order, they are： Hindeodus parvus zone, Isarcicella lobata zone, Isarcicella isarcica zone and Hindeodus sosioensis zone. The age of microbialite in the P–T transition at the Dajiang Section is considered to be within the Hindeodus parvus zone and thus to clearly post-date the main extinction crisis. Reviewing the age of onset of microbialites throughout the Tethyan regions reveals two different ages： a Hindeodus changxingensis zone age is dominant in south-western and westernmost Tethys, whilst most other regions show microbialite deposition began in the Hindeodus parvus zone. Our investigation also indicates that two conodont changes occur at this time： an increase of hindeodid species immediately following a sequence boundary and the mass extinction, and a phase of extinction losses in the earliest Triassic Isarcicella isarcica zone during highstand development.
基金supported by the National Basic Research Program of China(Grant No.2011CB808800)the 111 Project(Grant No.B08030)+1 种基金the National Natural Science Foundation of China(Grant Nos.40621002,40830212&40921062)the Fundamental Research Funds for the Central Universities(CUG130407)
文摘The greatest Phanerozoic mass extinction happened at the end-Permian to earliest Triassic. About 95% species, 82% genera, and more than half families became extinct, constituting the sole macro-mass extinction in geological history. This event not only caused the great extinction but also destroyed the 200 Myr-long Paleozoic marine ecosystem, prompted its transition to Mesozoic ecosystem, and induced coal gap on land as well as reef gap and chert gap in ocean. The biotic crisis during the Paleozoic-Mesozoic transition was a long process of co-evolution between geospheres and biosphere. The event sequence at the Permian-Triassic boundary （PTB） reveals two-episodic pattern of rapidly deteriorating global changes and biotic mass ex- tinction and the intimate relationship between them. The severe global changes coupling multiple geospheres may have affect- ed the Pangea integration on the Earth＇s surface spheres, which include： the Pangea integration→enhanced mountain height and basin depth, changes of wind and ocean current systems; enhanced ocean basin depth→the greatest Phanerozoic regression at PTB, disappearance of epeiric seas and subsequent rapid transgression; the Pangea integration→thermal isolation effect of continental lithosphere and decrease of mid-ocean ridges→development of continental volcanism; two-episode volcanism causing LIPs of the Emeishan Basalt and the Siberian Trap （25%251 Ma）→global warming and mass extinction; continental aridification and replacement of monsoon system by latitudinal wind system→destruction of vegetation; enhanced weathering and CH4 emission→negative excursion of δ^13C; mantle plume→crust doming→regression; possible relation between the Illawarra magnetic reversal and the PTB extinction, and so on. Mantle plume produced the Late Permian LIPs and mantle convection may have caused the process of the Pangea integration. Subduction, delamination, and accumulation of the earth＇s cool lithospheric material at the ＂D＂ layer of CMB started mantl
基金supported by the Special Scientific Research Funds for Environment Protection Commonweal Section (Grant Nos 200809143 and 201009001)Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No IAP09320)
文摘The objective of this study was to reconstruct light extinction coefficients （b ext ） according to chemical composition components of particulate matter up to 2.5 μm in size （PM 2.5 ）. PM 2.5 samples were collected at the monitoring station of the South China of Institute of Environmental Science （SCIES, Guangzhou, China） during January 2010, and the online absorbing and scattering coefficients were obtained using an aethalometer and a nephelometer. The measured values of light absorption coefficient by particle （b ap ） and light scattering coefficient by particle （b sp ） significantly correlated （R 2 0.95） with values of b ap and b sp that were reconstructed using the Interagency Monitoring of Protected Visual Environments （IMPROVE） formula when RH was 70%. The measured b ext had a good correlation （R 2 0.83） with the calculated b ext under ambient RH conditions. The result of source apportionment of b ext showed that ammonium sulfate [（NH 4 ） 2 SO 4 ] was the largest contributor （35.0%） to b ext , followed by ammonium nitrate （NH 4 NO 3 , 22.9%）, organic matter （16.1%）, elemental carbon （11.8%）, sea salt （4.7%）, and nitrogen dioxide （NO 2 , 9.6%）. To improve visibility in Guangzhou, the effective control of secondary particles like sulfates, nitrates, and ammonia should be given more attention in urban environmental management.
