Approximately 230 million years ago in the middle of the Carnian stage of the Upper Triassic, the sedimentary records in different regional basins display dramatic changes. Tropical carbonate platforms abruptly ended,...Approximately 230 million years ago in the middle of the Carnian stage of the Upper Triassic, the sedimentary records in different regional basins display dramatic changes. Tropical carbonate platforms abruptly ended, and engorged river systems left widespread sand-rich layers across inland basins and coastal regions. This pulse lasted less than a million years in some basins, but constituted a permanent shift in others. Following this event, the Late Carnian has the earliest record of significant dinosaurs on land and the emergence of the calcareous nannoplankton in the oceans that now govern Earth＇s carbon cycle. This ＂most distinctive climate change within the Tri- assic＂ has been interpreted by some geoscientists as a global disruption of the Earth＇s land-ocean-biological system. The eruption of the Wrangellia large igneous province may have been the trigger for a sudden carbon-dioxide-induced warming and associated increased rainfall in some of these regions. Indeed, some workers have proposed that this ＂wet intermezzo＂ warming event is a useful analog to aid in predicting the effects of our future greenhouse on land ecosystems and ocean chemistry. However, the understanding of the onset, duration, global impacts and relatively rapid termination of this postulated warming pulse has been hindered by lack of a global dataset with inter-calibrated terrestrial and marine biostratigraphy, precise radio-isotopic ages, stable isotope records of temperature and the carbon system, and cycle-calibrated rates of regional and global change.展开更多
Successive evolutionary trends control the genera Paragondolella Mosher and Meta- polygnathus Hayashi over the about 20 Ma long Aegean-Tuvalian timespan. In consideration of their evolutionary criteria, these genera h...Successive evolutionary trends control the genera Paragondolella Mosher and Meta- polygnathus Hayashi over the about 20 Ma long Aegean-Tuvalian timespan. In consideration of their evolutionary criteria, these genera have been retained together with Carnepigondolella Kozur and the two new genera proposed herein, MazzaeUa （type species M. carnica） and Hayashiella （type species H. nodosa）. Mazzaella n. gen. represents a Late Julian side branch ofMetapolygnathus, harbouring a platform ornamentation similar to the several million years younger Tuvalian lineage of Carnepigondolella, issued from Hayashiella n. gen. that is intermediary between Metapolygnathus and CarnepigondoleUa, based on appearance and platform ornamentation.展开更多
The Carnian Pluvial Episode(CPE)fingerprints global environmental perturbations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province(LIP).However,the correlat...The Carnian Pluvial Episode(CPE)fingerprints global environmental perturbations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province(LIP).However,the correlation between terrestrial environmental changes and Wrangellia volcanism in the Ordos Basin during the CPE remains poorly understood.Records of negative carbon isotopic excursions(NCIEs),mercury(Hg),Hg/TOC,and Hg enrichment factor(HgEF)from oil shales in a large-scale terrestrial Ordos Basin in the Eastern Tethys were correlated with marine and other terrestrial successions.The three significant NCIEs in the study section were consistently correlated with those in the CPE successions of Europe,the UK,and South and North China.The U-Pb geochronology indicates a Ladinian-Carnian age for the Chang 7 Member.A comprehensive overview of the geochronology,NCIE correlation,and previous bio-and chronostratigraphic frameworks shows that the Ladinian-Carnian boundary is located in the lower part of Chang 7 in the Yishicun section.HgEF may be a more reliable proxy for tracing volcanic eruptions than the Hg/TOC ratio because the accumulation rates of TOC content largely vary in terrestrial and marine successions.The records of Hg,Hg/TOC,HgEF,and NCIEs in the Ordos Basin aligned with Carnian successions worldwide and were marked by similar anomalies,indicating a global response to the Wrangellia LIP during the CPE.Anoxia,a warm-humid climate,enhancement of detrital input,and NCIEs are synchronous with the CPE interval in the Ordos Basin,which suggests that the CPE combined with the regional Qinling Orogeny should dominate the enhanced rate of terrigenous input and paleoenvironmental evolution in the Ordos Basin.展开更多
NORTHWEST Sichuan, a hotspot for geologic study, recently has yielded a series of large-medi-um scale gold deposits in the Upper Triassic. It is of great importance to determination andsubdivision of the Triassic Syst...NORTHWEST Sichuan, a hotspot for geologic study, recently has yielded a series of large-medi-um scale gold deposits in the Upper Triassic. It is of great importance to determination andsubdivision of the Triassic System and eventually to exact locating of the gold deposits.The Triassic Zagunao Formation in northwestern Sichuan has greatly changed in sensesince it was named in 1961. Now the Zagunao Formation only includes the metamorphic sand-stone with interlayers of slate lying between the Zhuwo Formation （T<sub>3</sub>） and the Zagashan For-展开更多
为研究卡尼期雨幕事件在鄂尔多斯盆地南部的响应,对该盆地ZH2钻孔延长组进行孢粉化石、有机碳同位素、草莓状黄铁矿和主量元素分析。孢粉化石由下至上划分出Punctatisporites-Verrucosisporites-Osmundacidites组合Ⅰ和Asseretospora-Ap...为研究卡尼期雨幕事件在鄂尔多斯盆地南部的响应,对该盆地ZH2钻孔延长组进行孢粉化石、有机碳同位素、草莓状黄铁矿和主量元素分析。孢粉化石由下至上划分出Punctatisporites-Verrucosisporites-Osmundacidites组合Ⅰ和Asseretospora-Apiculatisporis组合Ⅱ,地质年代分别为中三叠世拉丁期和晚三叠世卡尼期。在孢粉组合Ⅱ下部张家滩页岩中总有机碳富集、有机碳同位素发生负漂移,漂移量为4.88‰,同时草莓状黄铁矿指标指示着该层位形成于贫氧的环境,Al_(2)O_(3)/MgO比值和化学蚀变指数(chemical index of alteration,CIA)值在该层位均处于高值,指示着高温、湿润、强化学风化的环境。以上特征表明卡尼期雨幕事件在鄂尔多斯盆地造成了显著影响。进一步分析显示这些指标在张家滩页岩中可划分为4个独立的高温、湿润、缺氧、有机碳富集片段,指示了卡尼期雨幕事件(Carnian pluvial event,CPE)在鄂尔多斯盆地的4次气候波动,分别命名为:CPEⅠ、CPEⅡ、CPEⅢ、CPEⅣ。展开更多
In recent years,two species of fossil plants,i.e.Ctenozamites sarrani Zeiller and Equisetites arenaceus(Jaeger)Bronn,have been found for the first time in the Xiaowa Formation in Guanling County,Guizhou.They occur tog...In recent years,two species of fossil plants,i.e.Ctenozamites sarrani Zeiller and Equisetites arenaceus(Jaeger)Bronn,have been found for the first time in the Xiaowa Formation in Guanling County,Guizhou.They occur together with marine reptiles,crinoids,ammonites,bivalves,conodonts,fishes,brachiopods etc.The Xiaowa Formation is composed of a sequence of marine deposits,in which fossil plants may have been carried to the bay from the land not far from the coast by rivers and deposited there.This finding not only adds a new element to the Guanling biota,but also provides further evidence for determining this biota to be of Carnian age.展开更多
基金Support for this Mid-Carnian preparation wasprovided by a visiting professorship at the State Key Laboratory of Geobiology and Environmental Geology of the China University of Geosciences at Wuhan, China,and by a visiting-scholar sabbatical hosted by the Geosciences Australia in Canberra, Australia
文摘Approximately 230 million years ago in the middle of the Carnian stage of the Upper Triassic, the sedimentary records in different regional basins display dramatic changes. Tropical carbonate platforms abruptly ended, and engorged river systems left widespread sand-rich layers across inland basins and coastal regions. This pulse lasted less than a million years in some basins, but constituted a permanent shift in others. Following this event, the Late Carnian has the earliest record of significant dinosaurs on land and the emergence of the calcareous nannoplankton in the oceans that now govern Earth＇s carbon cycle. This ＂most distinctive climate change within the Tri- assic＂ has been interpreted by some geoscientists as a global disruption of the Earth＇s land-ocean-biological system. The eruption of the Wrangellia large igneous province may have been the trigger for a sudden carbon-dioxide-induced warming and associated increased rainfall in some of these regions. Indeed, some workers have proposed that this ＂wet intermezzo＂ warming event is a useful analog to aid in predicting the effects of our future greenhouse on land ecosystems and ocean chemistry. However, the understanding of the onset, duration, global impacts and relatively rapid termination of this postulated warming pulse has been hindered by lack of a global dataset with inter-calibrated terrestrial and marine biostratigraphy, precise radio-isotopic ages, stable isotope records of temperature and the carbon system, and cycle-calibrated rates of regional and global change.
文摘Successive evolutionary trends control the genera Paragondolella Mosher and Meta- polygnathus Hayashi over the about 20 Ma long Aegean-Tuvalian timespan. In consideration of their evolutionary criteria, these genera have been retained together with Carnepigondolella Kozur and the two new genera proposed herein, MazzaeUa （type species M. carnica） and Hayashiella （type species H. nodosa）. Mazzaella n. gen. represents a Late Julian side branch ofMetapolygnathus, harbouring a platform ornamentation similar to the several million years younger Tuvalian lineage of Carnepigondolella, issued from Hayashiella n. gen. that is intermediary between Metapolygnathus and CarnepigondoleUa, based on appearance and platform ornamentation.
基金supported by the National Natural Science Foundation of China(Grant Nos.42172109,41872113,42172108)China National Petroleum Corporation-China University of Petroleum(Beijing)Strategic Cooperation Science and Technology Project(Grant No.ZLZX2020-02)+1 种基金State's Key Project of Research and Development Plan(Grant No.2018YFA0702405)Science Foundation of China University of Petroleum(Beijing)(Grant Nos.2462020BJRC002,2462020YXZZ020)。
文摘The Carnian Pluvial Episode(CPE)fingerprints global environmental perturbations and biological extinction on land and oceans and is potentially linked to the Wrangellia Large Igneous Province(LIP).However,the correlation between terrestrial environmental changes and Wrangellia volcanism in the Ordos Basin during the CPE remains poorly understood.Records of negative carbon isotopic excursions(NCIEs),mercury(Hg),Hg/TOC,and Hg enrichment factor(HgEF)from oil shales in a large-scale terrestrial Ordos Basin in the Eastern Tethys were correlated with marine and other terrestrial successions.The three significant NCIEs in the study section were consistently correlated with those in the CPE successions of Europe,the UK,and South and North China.The U-Pb geochronology indicates a Ladinian-Carnian age for the Chang 7 Member.A comprehensive overview of the geochronology,NCIE correlation,and previous bio-and chronostratigraphic frameworks shows that the Ladinian-Carnian boundary is located in the lower part of Chang 7 in the Yishicun section.HgEF may be a more reliable proxy for tracing volcanic eruptions than the Hg/TOC ratio because the accumulation rates of TOC content largely vary in terrestrial and marine successions.The records of Hg,Hg/TOC,HgEF,and NCIEs in the Ordos Basin aligned with Carnian successions worldwide and were marked by similar anomalies,indicating a global response to the Wrangellia LIP during the CPE.Anoxia,a warm-humid climate,enhancement of detrital input,and NCIEs are synchronous with the CPE interval in the Ordos Basin,which suggests that the CPE combined with the regional Qinling Orogeny should dominate the enhanced rate of terrigenous input and paleoenvironmental evolution in the Ordos Basin.
文摘NORTHWEST Sichuan, a hotspot for geologic study, recently has yielded a series of large-medi-um scale gold deposits in the Upper Triassic. It is of great importance to determination andsubdivision of the Triassic System and eventually to exact locating of the gold deposits.The Triassic Zagunao Formation in northwestern Sichuan has greatly changed in sensesince it was named in 1961. Now the Zagunao Formation only includes the metamorphic sand-stone with interlayers of slate lying between the Zhuwo Formation （T<sub>3</sub>） and the Zagashan For-
文摘为研究卡尼期雨幕事件在鄂尔多斯盆地南部的响应,对该盆地ZH2钻孔延长组进行孢粉化石、有机碳同位素、草莓状黄铁矿和主量元素分析。孢粉化石由下至上划分出Punctatisporites-Verrucosisporites-Osmundacidites组合Ⅰ和Asseretospora-Apiculatisporis组合Ⅱ,地质年代分别为中三叠世拉丁期和晚三叠世卡尼期。在孢粉组合Ⅱ下部张家滩页岩中总有机碳富集、有机碳同位素发生负漂移,漂移量为4.88‰,同时草莓状黄铁矿指标指示着该层位形成于贫氧的环境,Al_(2)O_(3)/MgO比值和化学蚀变指数(chemical index of alteration,CIA)值在该层位均处于高值,指示着高温、湿润、强化学风化的环境。以上特征表明卡尼期雨幕事件在鄂尔多斯盆地造成了显著影响。进一步分析显示这些指标在张家滩页岩中可划分为4个独立的高温、湿润、缺氧、有机碳富集片段,指示了卡尼期雨幕事件(Carnian pluvial event,CPE)在鄂尔多斯盆地的4次气候波动,分别命名为:CPEⅠ、CPEⅡ、CPEⅢ、CPEⅣ。
文摘In recent years,two species of fossil plants,i.e.Ctenozamites sarrani Zeiller and Equisetites arenaceus(Jaeger)Bronn,have been found for the first time in the Xiaowa Formation in Guanling County,Guizhou.They occur together with marine reptiles,crinoids,ammonites,bivalves,conodonts,fishes,brachiopods etc.The Xiaowa Formation is composed of a sequence of marine deposits,in which fossil plants may have been carried to the bay from the land not far from the coast by rivers and deposited there.This finding not only adds a new element to the Guanling biota,but also provides further evidence for determining this biota to be of Carnian age.
