1 Introduction As one of the major groups in the Great Ordovician Biodiversification Event(GOBE),cephalopods may have played a critical role in the marine ecosystem in late Cambrian and Ordovician.Among the few predat...1 Introduction As one of the major groups in the Great Ordovician Biodiversification Event(GOBE),cephalopods may have played a critical role in the marine ecosystem in late Cambrian and Ordovician.Among the few predators in the Ordovician,cephalopods are typified by their big sizes and the development of swimming ability.展开更多
A robust stratigraphic framework and a coherent depositional ramp model for the Zitai,Dawan,Meitan and Ningkuo formations of Floian–Darriwilian age(Early–Middle Ordovician)in the Yangtze(Daoba,Xiangshuidong,Daling,G...A robust stratigraphic framework and a coherent depositional ramp model for the Zitai,Dawan,Meitan and Ningkuo formations of Floian–Darriwilian age(Early–Middle Ordovician)in the Yangtze(Daoba,Xiangshuidong,Daling,Gudongkou and Honghuayuan sections)and Jiangnan regions(Nanba section)was created based on lithofacies and major element analysis.Three siliciclastic(LF1–3)and six carbonate(LF4–9)lithofacies are recognized representing sediments that were deposited in mixed siliciclastic and carbonate ramp environment.The intensity of mixed sedimentation and terrigenous input were evaluated using the elemental proxies Intensity of Mixed sedimentation(IM)and Aluminum Accumulation Rate(Al AR),as well as their mean values during certain time intervals.Mixed sediments are most well-developed along the marginal Yangtze region,strongly impacted by recurrent influx of westerly derived terrigenous materials in response to global eustatic changes and regional tectonic movements,shaping the gently southeast-dipping morphology.Regular terrigenous influx resulted in periods of enhanced primary productivity on the Yangtze Ramp as evidenced by matching biodiversity peaks in planktonic organisms,i.e.,chitinozoans and acritarchs.Brachiopods and other shelly fauna were also able to proliferate as new niches developed along the gently dipping ramp floor with substrate changes.The biodiversification patterns suggest that terrigenous influx controlled in part by regional tectonics played a more important role than previously thought in the development of Great Ordovician Biodiversification Event in South China.展开更多
Ostracods are described for the first time from the red-coloured marine sandstones of Arisu section(Arisu red beds)of the Upper Ordovician Tierekeawati Formation in Kalpin area of northwestern Tarim Basin, Xinjiang Uy...Ostracods are described for the first time from the red-coloured marine sandstones of Arisu section(Arisu red beds)of the Upper Ordovician Tierekeawati Formation in Kalpin area of northwestern Tarim Basin, Xinjiang Uygur Autonomous Region(Xinjiang), Northwest China. Twenty-two species belonging to thirteen genera are described and figured. The ostracod fauna suggests a probable Sandbian–Katian age for these beds. The palaeoecological assemblage of ostracod fauna implies the deposition in a nearshore-offshore environment during a regression when the Arisu red beds of the Tierekeawati Formation were laid down in the Tarim Basin. Many cosmopolitan and provincial genera were present in diversified ostracod fauna of the Arisu red beds, suggesting the possible biogeographic relationships among the Tarim, Tibet, and South China plates, as well as Europe and North America continents during the Late Ordovician. Ostracods experienced faunal exchanges between Laurentia and the Tarim Plate during the Late Ordovician Period.展开更多
基金supported by the Chinese Academy of Sciences(Grant Nos.XDB26000000,XDB10010100)the Ministry of Science and Technology of China(Grant Nos.2013FY111000,2017ZX05036-001-004)+1 种基金the National Natural Science Foundation of China(Grant No.41772005)IGCP project 653’The Onset of the Great Ordovician Biodiversification Event’.
文摘1 Introduction As one of the major groups in the Great Ordovician Biodiversification Event(GOBE),cephalopods may have played a critical role in the marine ecosystem in late Cambrian and Ordovician.Among the few predators in the Ordovician,cephalopods are typified by their big sizes and the development of swimming ability.
基金funded by National Natural Science Foundation of China(Grant Nos.42102130,41972011)Natural Science Foundation of Jiangsu Province(Grant No.BK20191101)+2 种基金Chinese Academy of Sciences(Grant No.XDB26000000)China Scholarship Council(Grant No.202004910207)State Key Laboratory of Palaeobiology and Stratigraphy。
文摘A robust stratigraphic framework and a coherent depositional ramp model for the Zitai,Dawan,Meitan and Ningkuo formations of Floian–Darriwilian age(Early–Middle Ordovician)in the Yangtze(Daoba,Xiangshuidong,Daling,Gudongkou and Honghuayuan sections)and Jiangnan regions(Nanba section)was created based on lithofacies and major element analysis.Three siliciclastic(LF1–3)and six carbonate(LF4–9)lithofacies are recognized representing sediments that were deposited in mixed siliciclastic and carbonate ramp environment.The intensity of mixed sedimentation and terrigenous input were evaluated using the elemental proxies Intensity of Mixed sedimentation(IM)and Aluminum Accumulation Rate(Al AR),as well as their mean values during certain time intervals.Mixed sediments are most well-developed along the marginal Yangtze region,strongly impacted by recurrent influx of westerly derived terrigenous materials in response to global eustatic changes and regional tectonic movements,shaping the gently southeast-dipping morphology.Regular terrigenous influx resulted in periods of enhanced primary productivity on the Yangtze Ramp as evidenced by matching biodiversity peaks in planktonic organisms,i.e.,chitinozoans and acritarchs.Brachiopods and other shelly fauna were also able to proliferate as new niches developed along the gently dipping ramp floor with substrate changes.The biodiversification patterns suggest that terrigenous influx controlled in part by regional tectonics played a more important role than previously thought in the development of Great Ordovician Biodiversification Event in South China.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 41802002,41872035 and 41702003)Strategic Priority Research Program (B) of Chinese Academy of Sciences(Grant No. XDB26000000)。
文摘Ostracods are described for the first time from the red-coloured marine sandstones of Arisu section(Arisu red beds)of the Upper Ordovician Tierekeawati Formation in Kalpin area of northwestern Tarim Basin, Xinjiang Uygur Autonomous Region(Xinjiang), Northwest China. Twenty-two species belonging to thirteen genera are described and figured. The ostracod fauna suggests a probable Sandbian–Katian age for these beds. The palaeoecological assemblage of ostracod fauna implies the deposition in a nearshore-offshore environment during a regression when the Arisu red beds of the Tierekeawati Formation were laid down in the Tarim Basin. Many cosmopolitan and provincial genera were present in diversified ostracod fauna of the Arisu red beds, suggesting the possible biogeographic relationships among the Tarim, Tibet, and South China plates, as well as Europe and North America continents during the Late Ordovician. Ostracods experienced faunal exchanges between Laurentia and the Tarim Plate during the Late Ordovician Period.
