On the basis of a study of the acanthomorphic acritarchs discovered in the Late Proterozoicto Early Cambrian Meishucunian Stage in different regions of China, especially in southernShaanxi and the Yangtze Platform, co...On the basis of a study of the acanthomorphic acritarchs discovered in the Late Proterozoicto Early Cambrian Meishucunian Stage in different regions of China, especially in southernShaanxi and the Yangtze Platform, coupled with a study of the assemblages, morphological cor-relation, microstructure, and evolutional relations of the acanthorphic acritarchs, as well as awide correlation with those found in different regions of the world, the authors discuss the earlyevolutionary stages of the acanthomorphs, features of their assemblages in various stages, theirbiostratigraphical significance, and their evolutionary trend in China.展开更多
Abundant phosphatized acritarchs are preserved in the late Precambrian （Ediacaran） Doushantuo Formation at Weng＇an, Guizhou Province, southwest China. Most of them are large with various spinous ornaments and multi...Abundant phosphatized acritarchs are preserved in the late Precambrian （Ediacaran） Doushantuo Formation at Weng＇an, Guizhou Province, southwest China. Most of them are large with various spinous ornaments and multilayered outer walls. The general characters of these fossils are quite similar to those found from the homochronous deposits of the Yangtze Gorges, southern China. Therefore the Doushantuo Formation in the Weng＇an area can be correlated directly with the Doushantuo Formation of the Yangtze Gorges. Four species in four genera, including two new genera, two new species and one uncertain species are systematically described for the first time from the studied locality. The taxa are Bacatisphaera baokangensis Zhou, Brasier et Xue, 2001, Taeniosphaera doushantuoensis gen. et sp. nov., Rugospinasphaera speciosa gen. et sp. nov. and Meghystichosphaeridium sp. The new data enriches the famous Weng＇an biota, especially the marine microplankton flora in the Ediacaran Doushantuo Formation.展开更多
The latest Permian extinction(252 Myr ago)was the most severe in the geologic record.On land,widespread Late Permian gymnosperm/seed-fern dominated forests appear to have suffered rapid and almost complete destruction...The latest Permian extinction(252 Myr ago)was the most severe in the geologic record.On land,widespread Late Permian gymnosperm/seed-fern dominated forests appear to have suffered rapid and almost complete destruction,as evidenced by increased soil erosion and changes in fluvial style in deforested areas,signs of wildfires,replacement of trees by lower plants,and almost complete loss of peat-forming and fire-susceptible vegetation.Permian-Triassic boundary strata at many sites show two widespread palynological events in the wake of the forest destruction:The fungal event,evidenced by a thin zone with>95%fungal cells(Reduviasporonites)and woody debris,found in terrestrial and marine sediments,and the acritarch event,marked by the sudden flood of unusual phytoplankton in the marine realm.These two events represent the global temporary explosive spread of stress-tolerant and opportunistic organisms on land and in the sea just after the latest Permian disaster.They represent unique events,and thus they can provide a time marker in correlating latest Permian marine and terrestrial sequences.展开更多
STAPLIN revealed that palaeoenvironment changes seem to control acritarch distribution patterns. However, scientists have been puzzled by the fact that characteristic offshore acritarchs occur with nearshore ones. Thi...STAPLIN revealed that palaeoenvironment changes seem to control acritarch distribution patterns. However, scientists have been puzzled by the fact that characteristic offshore acritarchs occur with nearshore ones. This note demonstrates depth zonation of Arenigian acritarchs in South China and reveals the variation of water depth in South China during the Arenig Age.展开更多
Recently, we delved into Precambrian shale-facies microfossils of China by observation from petrographic thin sections. After having examined a large number of thin sections cut parallel to lamination under the light ...Recently, we delved into Precambrian shale-facies microfossils of China by observation from petrographic thin sections. After having examined a large number of thin sections cut parallel to lamination under the light microscope, we discovered an interesting phenomenon, acritarchs with post-burial contraction cracks.展开更多
Fluorescence properties of Early Cambrian acri-tarchs were investigated using Leica das Mikroskop(DM)microscopy with a mercury lamp.Well-preserved autoflures-cence properties show a correlation between acritarchs morp...Fluorescence properties of Early Cambrian acri-tarchs were investigated using Leica das Mikroskop(DM)microscopy with a mercury lamp.Well-preserved autoflures-cence properties show a correlation between acritarchs morphology and the intensity of emitted fluorescence.In accordance with the fluorescence intensity of organic cell walls,two groups of microfossils were distinguished.Results of observation in this study,which are consistent with those of the previous foreign studies,are in good agreement with regular difference in autofluorescence intensity among paly-nomorphs reported by McPhilemy(1998).Spores and algae,including Botryococcus,have very bright fluorescence while acritarchs often show less intense fluorescence.Dark brown microfossils have been reworked,and have little or no fluorescence.展开更多
As primary producers,acritarchs that represented the base of the food chain in the Early Paleozoic marine ecosystem formed the marine phytoplankton communities whose distributions might affect those of other faunas.Te...As primary producers,acritarchs that represented the base of the food chain in the Early Paleozoic marine ecosystem formed the marine phytoplankton communities whose distributions might affect those of other faunas.Ten acritarch ecological assemblages with their distributions controlled by the environmental factors were recognized in the Meitan Formation of the Honghuayuan section,Tongzi,Guizhou Province,the Dawan Formation of the Huanghuachang and Daping section,Yichang,Hubei Province,and the Dacao Formation and the Yingpan Formation of the Houping section,Chengkou,Chongqing through cluster and principle component analysis.展开更多
As the primary producers, acritarchs represent the base of the food chain in the Paleozoic marine ecosystem which links with the evolution of acritarchs. Based on high precision quantitative research, much information...As the primary producers, acritarchs represent the base of the food chain in the Paleozoic marine ecosystem which links with the evolution of acritarchs. Based on high precision quantitative research, much information about Paleozoic marine ecosystem is provided. A quantitative analysis of Early-Middle Ordovician acritarch diversity changes in the Meitan Formation, Honghuayuan section, Tongzi, Guizhou is made and the the acritarch diversity curves are compared with sea level curves. We found that acritarch diversity changes were related to sea level changes during the Early-Middle Ordovician. Whereas sea level rose, and acritarch diversity also increased. An inshore-offshore model of acritarchs best explains the relative abundance changes of some acritarch taxa in relation to sea level changes.展开更多
基金Note:This study was supported by the China National Natural Science Foundation Grant No.49172071 and the Foundation for Development of Geological Science and Technology of the Ministry of Geology and Mineral Resources
文摘On the basis of a study of the acanthomorphic acritarchs discovered in the Late Proterozoicto Early Cambrian Meishucunian Stage in different regions of China, especially in southernShaanxi and the Yangtze Platform, coupled with a study of the assemblages, morphological cor-relation, microstructure, and evolutional relations of the acanthorphic acritarchs, as well as awide correlation with those found in different regions of the world, the authors discuss the earlyevolutionary stages of the acanthomorphs, features of their assemblages in various stages, theirbiostratigraphical significance, and their evolutionary trend in China.
基金funded by the National Natural Science Foundation of China(Grant No.440272015)the China Geological Survey(Grant No.200213000042).
文摘Abundant phosphatized acritarchs are preserved in the late Precambrian （Ediacaran） Doushantuo Formation at Weng＇an, Guizhou Province, southwest China. Most of them are large with various spinous ornaments and multilayered outer walls. The general characters of these fossils are quite similar to those found from the homochronous deposits of the Yangtze Gorges, southern China. Therefore the Doushantuo Formation in the Weng＇an area can be correlated directly with the Doushantuo Formation of the Yangtze Gorges. Four species in four genera, including two new genera, two new species and one uncertain species are systematically described for the first time from the studied locality. The taxa are Bacatisphaera baokangensis Zhou, Brasier et Xue, 2001, Taeniosphaera doushantuoensis gen. et sp. nov., Rugospinasphaera speciosa gen. et sp. nov. and Meghystichosphaeridium sp. The new data enriches the famous Weng＇an biota, especially the marine microplankton flora in the Ediacaran Doushantuo Formation.
文摘The latest Permian extinction(252 Myr ago)was the most severe in the geologic record.On land,widespread Late Permian gymnosperm/seed-fern dominated forests appear to have suffered rapid and almost complete destruction,as evidenced by increased soil erosion and changes in fluvial style in deforested areas,signs of wildfires,replacement of trees by lower plants,and almost complete loss of peat-forming and fire-susceptible vegetation.Permian-Triassic boundary strata at many sites show two widespread palynological events in the wake of the forest destruction:The fungal event,evidenced by a thin zone with>95%fungal cells(Reduviasporonites)and woody debris,found in terrestrial and marine sediments,and the acritarch event,marked by the sudden flood of unusual phytoplankton in the marine realm.These two events represent the global temporary explosive spread of stress-tolerant and opportunistic organisms on land and in the sea just after the latest Permian disaster.They represent unique events,and thus they can provide a time marker in correlating latest Permian marine and terrestrial sequences.
文摘STAPLIN revealed that palaeoenvironment changes seem to control acritarch distribution patterns. However, scientists have been puzzled by the fact that characteristic offshore acritarchs occur with nearshore ones. This note demonstrates depth zonation of Arenigian acritarchs in South China and reveals the variation of water depth in South China during the Arenig Age.
文摘Recently, we delved into Precambrian shale-facies microfossils of China by observation from petrographic thin sections. After having examined a large number of thin sections cut parallel to lamination under the light microscope, we discovered an interesting phenomenon, acritarchs with post-burial contraction cracks.
基金This work was supported by the“Western China Light”Science Foundation(Chinese Academy of Science)(No.0240401)State Key Laboratory of Palaeobiology and Stratigraphy(Nanjing Institute of Geology and Palaeontology,Chinese Academy of Science)(No.073105).
文摘Fluorescence properties of Early Cambrian acri-tarchs were investigated using Leica das Mikroskop(DM)microscopy with a mercury lamp.Well-preserved autoflures-cence properties show a correlation between acritarchs morphology and the intensity of emitted fluorescence.In accordance with the fluorescence intensity of organic cell walls,two groups of microfossils were distinguished.Results of observation in this study,which are consistent with those of the previous foreign studies,are in good agreement with regular difference in autofluorescence intensity among paly-nomorphs reported by McPhilemy(1998).Spores and algae,including Botryococcus,have very bright fluorescence while acritarchs often show less intense fluorescence.Dark brown microfossils have been reworked,and have little or no fluorescence.
基金supported by the National Natural Science Foundation of China (Grant Nos.40802006,40672014 and J0630967)LPS (Grant No.083108)
文摘As primary producers,acritarchs that represented the base of the food chain in the Early Paleozoic marine ecosystem formed the marine phytoplankton communities whose distributions might affect those of other faunas.Ten acritarch ecological assemblages with their distributions controlled by the environmental factors were recognized in the Meitan Formation of the Honghuayuan section,Tongzi,Guizhou Province,the Dawan Formation of the Huanghuachang and Daping section,Yichang,Hubei Province,and the Dacao Formation and the Yingpan Formation of the Houping section,Chengkou,Chongqing through cluster and principle component analysis.
基金supported by the National Natural Science Foundation of China(Grant No.40372009)Chinese Academy of Sciences(Grant Nos.KZCX2-SW-130,KZCX3-SW-149)the Ministry of Science and Technology of China(Grant Nos.G200077700,2003CB7 16805).
文摘As the primary producers, acritarchs represent the base of the food chain in the Paleozoic marine ecosystem which links with the evolution of acritarchs. Based on high precision quantitative research, much information about Paleozoic marine ecosystem is provided. A quantitative analysis of Early-Middle Ordovician acritarch diversity changes in the Meitan Formation, Honghuayuan section, Tongzi, Guizhou is made and the the acritarch diversity curves are compared with sea level curves. We found that acritarch diversity changes were related to sea level changes during the Early-Middle Ordovician. Whereas sea level rose, and acritarch diversity also increased. An inshore-offshore model of acritarchs best explains the relative abundance changes of some acritarch taxa in relation to sea level changes.
