On the basis of establishment of radiolarian biostratigraphy and conodont biostratigraphy, a radiolarian Albaillella fauna in the transitional environment from Guadalupian to Lopingian Series in Permian was found at a...On the basis of establishment of radiolarian biostratigraphy and conodont biostratigraphy, a radiolarian Albaillella fauna in the transitional environment from Guadalupian to Lopingian Series in Permian was found at a pelagic chert section in southeast Guangxi, South China. Radiolarian Albaillella is one of the most sensitive biology to the transitional environment. The Albaillella fauna shows an ecological evolutionary process from Guadalupian to Lopingian: declined stage-recovery stage-flourishing stage. The study of characteristics of the Albaillella fauna in the transitional environment may provide more information, not only for the subdivision and correlation of a high-resolution biostratigraphy, but also for influence of radiolarian Albaillella fauna on the pre-Lopingian mass extinction.展开更多
The Late Permian was marked by a series of important geological events and widespread organic-rich black shale depositions,acting as important unconventional hydrocarbon source rocks.However,the mechanism of organic m...The Late Permian was marked by a series of important geological events and widespread organic-rich black shale depositions,acting as important unconventional hydrocarbon source rocks.However,the mechanism of organic matter(OM)enrichment throughout this period is still controversial.Based on geochemical data,the marine redox conditions,paleogeographic and hydrographic environment,primary productivity,volcanism,and terrigenous input during the Late Permian in the Lower Yangtze region have been studied from the Putaoling section,Chaohu,to provide new insights into OM accumulation.Five Phases are distinguished based on the TOC and environmental variations.In Phase I,anoxic conditions driven by water restriction enhanced OM preservation.In Phase II,euxinic and cycling hydrological environments were the two most substantial controlling factors for the massive OM deposition.During Phase III,intensified terrestrial input potentially diluted the OM in sediment and the presence of oxygen in bottom water weakened the preservation condition.Phase IV was characterized by a relatively higher abundance of mercury(Hg)and TOC(peak at 16.98 wt%),indicating that enhanced volcanism potentially stimulated higher productivity and a euxinic environment.In Phase V,extremely lean OM was preserved as a result of terrestrial dilutions and decreasing primary productivity.Phases I,II and IV are characterized as the most prominent OM-rich zones due to the effective interactions of the controlling factors,namely paleogeographic,hydrographic environment,volcanism,and redox conditions.展开更多
This study recovered the Guadalupian conodont faunas from Shangsi （上寺） Section in Northeast Sichuan （四川）. Four genera and nine species were identified, and three conodont zones were recognized and established;...This study recovered the Guadalupian conodont faunas from Shangsi （上寺） Section in Northeast Sichuan （四川）. Four genera and nine species were identified, and three conodont zones were recognized and established; they include Jinogondolella nankingensis Zone, J. aserrata Zone, and J. postserrata Zone. The Roadian and Wordian boundary is set in the interval 5 m from the top of Bed 86 by the first appearance of the conodont J. aserrata. The Wordian and Capitanian boundary is set in the interval 2.3 m from the top of the Bed 95 by the first appearance ofJ. postserrata. Most of the specimens demonstrated low color alteration index （CAI） as 1.5-3, indicating that most part of the Maokou （茅口） Formation may have the suitable thermal conditions for the formation of oil source rocks.展开更多
In order to discuss the geochemical characteristic of REEs(rare earth elements) and their geological application,we measured the contents of rare earth elements,trace elements and minerals of 29 Lopingian(Late Permian...In order to discuss the geochemical characteristic of REEs(rare earth elements) and their geological application,we measured the contents of rare earth elements,trace elements and minerals of 29 Lopingian(Late Permian) mudstone samples in Panxian county,carrying out ICP-MS and XRD analysis.The results show that the amount of REEs(185.56-729.46 10à6) is high.The ratios of w(LREE)/w(HREE)(6.84-13.86) and w(La)N/w(Yb)N(1.01-3.02) show clear differentiation of LREEs and HREEs.RREE has a significantly or critically positive correlation with lithophile elements Th,Nb,Ta,Ti,Ga,Sc,Cs,Zr,Hf,Sr,Be and chalcophile element Zn,a critically negative correlation with siderophile element Fe and a slightly positive correlation with illite,illite smectite mixed layers and siderite.REEs originate mainly from terrigenous minerals,in an inorganic phase.Source rocks of our samples consist of Emeishan basalt and a small part of sedimentary rocks,as suggested by the distribution patterns of REEs and w(PREE)-w(La)/w(Yb) diagram.Moreover,abnormal surfaces near the sequence boundaries(SB2,SB3,SB4) are related with the boundaries,identifled by geochemical characteristics of the REEs,such as PREE,w(LREE)/w(HREE),Eu/Eu and Ceanom.展开更多
The late Permian(Lopingian)was a crucial climate transition period from the late Paleozoic Ice Age to the early Triassic of exceptionally high temperatures.However,the origins of the third-order sea-level changes duri...The late Permian(Lopingian)was a crucial climate transition period from the late Paleozoic Ice Age to the early Triassic of exceptionally high temperatures.However,the origins of the third-order sea-level changes during the Lopingian Epoch remain unclear.Here,we presented astronomically calibrated gamma-ray(GR)log and non-U GR(computed gamma ray or CGR)curves from the clastic and carbonate successions of well GFD-1 in the Pingle Depression of South China for studying the sea-level oscillations during the Lopingian.Spectral analyses of the 405 kyr-calibrated GR and CGR time data revealed periodicities close to about 405,about 100,about 44.2,about 35.1,about 21,and about 17.5 kyr,supporting the existence of Milankovitch forcing in the sedimentary records.A high-resolution astronomical time scale and high-resolution sedimentation rate curve of the Lopingian from well GFD-1 were constructed by cyclostratigraphic analysis.The eccentricity and obliquity amplitude modulation cycles suggested long periodicities of about 2.4 and about 1.2 myr,respectively.In the Wuchiapingian greenhouse of the Lopingian,the about 2.4 myr eccentricity oscillation controlled‘weak’glacio-eustasy and/or aquifer eustatic changes related to the global third-order sea-level changes and that a lowstand(W2)was initiated by an eccentricity oscillation minimum.In contrast,during the Changhsingian,which exhibited a cooling event,an about 1.2 myr obliquity cycle was probably strong,with the sea-level records highlighting the link between the‘icehouse’sea-level lowering(C2 and C1)and the obliquity nodes.Moreover,dynamic sedimentary noise model as an indicator of sea-level showed local third-order sea-level variations,the coevolution trends in the orbital power,global and local sea-level changes,and sedimentation rate had significant implications for establishing the global nature and synchronicity of these million-year-scale eustatic records and reconstructing the temporal depositional history at a regional scale.In addition,the volcanism and tectonism that continued into the early-middle Wuchiapingian probably led to a series of climate changes that drove the hydrological cycles not paced by the Milankovitch cycles.展开更多
The Permian-Triassic transition saw extreme climatic changes that severely impacted the terrestrial ecosystem.Fossil plants,particularly fossil woods,are sensitive to climatic changes,and they,therefore,are unique mat...The Permian-Triassic transition saw extreme climatic changes that severely impacted the terrestrial ecosystem.Fossil plants,particularly fossil woods,are sensitive to climatic changes,and they,therefore,are unique materials revealing extreme environmental and climatic changes on land at that time.Abundant conifer woods were discovered in the Lopingian(Late Permian)strata of the Sunjiagou Formation in Shanxi Province,North China.The newly finding permineralized woods record the unique landscape of Lopingian North China.They represent a new conifer genus and species:Shanxiopitys zhangziensis gen.et sp.nov.Analyses of growth pattern and anatomical characteristics of the fossil woods indicate these trees grew under optimal growing conditions,and without seasonal growth cessation.However,climate signals from leaf fossils,vertebrate fossils and sedimentary evidences indicate a strongly seasonal climate in North China during the Lopingian.Thus,it is speculated that these trees likely lived in the gallery forests,which were distributed along the paleo-rivers within a seasonal landscape in the central North China block during the Lopingian.展开更多
文摘On the basis of establishment of radiolarian biostratigraphy and conodont biostratigraphy, a radiolarian Albaillella fauna in the transitional environment from Guadalupian to Lopingian Series in Permian was found at a pelagic chert section in southeast Guangxi, South China. Radiolarian Albaillella is one of the most sensitive biology to the transitional environment. The Albaillella fauna shows an ecological evolutionary process from Guadalupian to Lopingian: declined stage-recovery stage-flourishing stage. The study of characteristics of the Albaillella fauna in the transitional environment may provide more information, not only for the subdivision and correlation of a high-resolution biostratigraphy, but also for influence of radiolarian Albaillella fauna on the pre-Lopingian mass extinction.
基金supported by the Fundamental and Commonwealth Geological Survey of Oil and Gas of China(Grant No.DD 20221662)the National Natural Science Foundation of China(NSFC)Program(Grant No.42302124).
文摘The Late Permian was marked by a series of important geological events and widespread organic-rich black shale depositions,acting as important unconventional hydrocarbon source rocks.However,the mechanism of organic matter(OM)enrichment throughout this period is still controversial.Based on geochemical data,the marine redox conditions,paleogeographic and hydrographic environment,primary productivity,volcanism,and terrigenous input during the Late Permian in the Lower Yangtze region have been studied from the Putaoling section,Chaohu,to provide new insights into OM accumulation.Five Phases are distinguished based on the TOC and environmental variations.In Phase I,anoxic conditions driven by water restriction enhanced OM preservation.In Phase II,euxinic and cycling hydrological environments were the two most substantial controlling factors for the massive OM deposition.During Phase III,intensified terrestrial input potentially diluted the OM in sediment and the presence of oxygen in bottom water weakened the preservation condition.Phase IV was characterized by a relatively higher abundance of mercury(Hg)and TOC(peak at 16.98 wt%),indicating that enhanced volcanism potentially stimulated higher productivity and a euxinic environment.In Phase V,extremely lean OM was preserved as a result of terrestrial dilutions and decreasing primary productivity.Phases I,II and IV are characterized as the most prominent OM-rich zones due to the effective interactions of the controlling factors,namely paleogeographic,hydrographic environment,volcanism,and redox conditions.
基金supported by the SINOPEC project (G0800-06-ZS-319)the National Natural Science Foundation of China (No. 40621002)+1 种基金the Program for Changjiang Scholars and Innovative Research Team (IRT0546)the "111" Project (No. B08030)
文摘This study recovered the Guadalupian conodont faunas from Shangsi （上寺） Section in Northeast Sichuan （四川）. Four genera and nine species were identified, and three conodont zones were recognized and established; they include Jinogondolella nankingensis Zone, J. aserrata Zone, and J. postserrata Zone. The Roadian and Wordian boundary is set in the interval 5 m from the top of Bed 86 by the first appearance of the conodont J. aserrata. The Wordian and Capitanian boundary is set in the interval 2.3 m from the top of the Bed 95 by the first appearance ofJ. postserrata. Most of the specimens demonstrated low color alteration index （CAI） as 1.5-3, indicating that most part of the Maokou （茅口） Formation may have the suitable thermal conditions for the formation of oil source rocks.
基金supported by the Key Program of the National Natural Science Foundation of China (No. 40730422)
文摘In order to discuss the geochemical characteristic of REEs(rare earth elements) and their geological application,we measured the contents of rare earth elements,trace elements and minerals of 29 Lopingian(Late Permian) mudstone samples in Panxian county,carrying out ICP-MS and XRD analysis.The results show that the amount of REEs(185.56-729.46 10à6) is high.The ratios of w(LREE)/w(HREE)(6.84-13.86) and w(La)N/w(Yb)N(1.01-3.02) show clear differentiation of LREEs and HREEs.RREE has a significantly or critically positive correlation with lithophile elements Th,Nb,Ta,Ti,Ga,Sc,Cs,Zr,Hf,Sr,Be and chalcophile element Zn,a critically negative correlation with siderophile element Fe and a slightly positive correlation with illite,illite smectite mixed layers and siderite.REEs originate mainly from terrigenous minerals,in an inorganic phase.Source rocks of our samples consist of Emeishan basalt and a small part of sedimentary rocks,as suggested by the distribution patterns of REEs and w(PREE)-w(La)/w(Yb) diagram.Moreover,abnormal surfaces near the sequence boundaries(SB2,SB3,SB4) are related with the boundaries,identifled by geochemical characteristics of the REEs,such as PREE,w(LREE)/w(HREE),Eu/Eu and Ceanom.
基金This work was supported by a National Natural Science Foundation of China(Grant No.91958210)the Government Finance Level II Project(No.DD20190083)‘the 13th Five-Year Plan’National Science and Technology Major Project(No.2016ZX05034001-003).
文摘The late Permian(Lopingian)was a crucial climate transition period from the late Paleozoic Ice Age to the early Triassic of exceptionally high temperatures.However,the origins of the third-order sea-level changes during the Lopingian Epoch remain unclear.Here,we presented astronomically calibrated gamma-ray(GR)log and non-U GR(computed gamma ray or CGR)curves from the clastic and carbonate successions of well GFD-1 in the Pingle Depression of South China for studying the sea-level oscillations during the Lopingian.Spectral analyses of the 405 kyr-calibrated GR and CGR time data revealed periodicities close to about 405,about 100,about 44.2,about 35.1,about 21,and about 17.5 kyr,supporting the existence of Milankovitch forcing in the sedimentary records.A high-resolution astronomical time scale and high-resolution sedimentation rate curve of the Lopingian from well GFD-1 were constructed by cyclostratigraphic analysis.The eccentricity and obliquity amplitude modulation cycles suggested long periodicities of about 2.4 and about 1.2 myr,respectively.In the Wuchiapingian greenhouse of the Lopingian,the about 2.4 myr eccentricity oscillation controlled‘weak’glacio-eustasy and/or aquifer eustatic changes related to the global third-order sea-level changes and that a lowstand(W2)was initiated by an eccentricity oscillation minimum.In contrast,during the Changhsingian,which exhibited a cooling event,an about 1.2 myr obliquity cycle was probably strong,with the sea-level records highlighting the link between the‘icehouse’sea-level lowering(C2 and C1)and the obliquity nodes.Moreover,dynamic sedimentary noise model as an indicator of sea-level showed local third-order sea-level variations,the coevolution trends in the orbital power,global and local sea-level changes,and sedimentation rate had significant implications for establishing the global nature and synchronicity of these million-year-scale eustatic records and reconstructing the temporal depositional history at a regional scale.In addition,the volcanism and tectonism that continued into the early-middle Wuchiapingian probably led to a series of climate changes that drove the hydrological cycles not paced by the Milankovitch cycles.
基金supported by the National Natural Sciences Foundation of China(Nos.92055201 and 31700183)。
文摘The Permian-Triassic transition saw extreme climatic changes that severely impacted the terrestrial ecosystem.Fossil plants,particularly fossil woods,are sensitive to climatic changes,and they,therefore,are unique materials revealing extreme environmental and climatic changes on land at that time.Abundant conifer woods were discovered in the Lopingian(Late Permian)strata of the Sunjiagou Formation in Shanxi Province,North China.The newly finding permineralized woods record the unique landscape of Lopingian North China.They represent a new conifer genus and species:Shanxiopitys zhangziensis gen.et sp.nov.Analyses of growth pattern and anatomical characteristics of the fossil woods indicate these trees grew under optimal growing conditions,and without seasonal growth cessation.However,climate signals from leaf fossils,vertebrate fossils and sedimentary evidences indicate a strongly seasonal climate in North China during the Lopingian.Thus,it is speculated that these trees likely lived in the gallery forests,which were distributed along the paleo-rivers within a seasonal landscape in the central North China block during the Lopingian.
