Reconstruction of the Yangtze Ramp during Floian to Darriwilian(Ordovician)in South China:Its Morphology,Controlling Factors and Significances  

作　　者：LUAN Xiaocong Andre DESROCHERS WU Rongchang LIU Jianbo WANG Guangxu LIANG Yan ZHANG Yuchen WEI Xin LI Lixia ZHAN Renbin 

机构地区：[1]State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,and Center for Excellence in Life and Paleoenvironment,Chinese Academy of Sciences,Nanjing 210008,China [2]Department of Geological Science,University of Saskatchewan,Saskatoon,Saskatchewan S7N 5E2,Canada [3]Department of Earth and Environmental Sciences,University of Ottawa,Ottawa,Ontario K1N 6N5,Canada [4]Paleontology and Stratigraphy,School of Earth and Space Sciences,Peking University,Beijing 100871,China [5]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Acta Geologica Sinica(English Edition)》2023年第6期1756-1777,共22页地质学报（英文版）

基　　金：funded by National Natural Science Foundation of China(Grant Nos.42102130,41972011);Natural Science Foundation of Jiangsu Province(Grant No.BK20191101);Chinese Academy of Sciences(Grant No.XDB26000000);China Scholarship Council(Grant No.202004910207);State Key Laboratory of Palaeobiology and Stratigraphy。

摘　　要：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.

关 键 词：mixed siliciclastic-carbonate sedimentation RAMP Stage Slice lithofacies major elements Great Ordovician Biodiversification Event(GOBE) 

分 类 号：P534.42[天文地球—古生物学与地层学]