Palaeontology And Stratigraphy Of The Late Sinian The West Yangtze Platform

On the basis of extensive field investigations and laboratory analyses on the Late Sinian strata and fossils in the west part of the Yangtze Platform, the Upper Sinian there has systematically been studied in lithostratigraphy, biostratigraphy and chronostratigraphy. At the same time, a diverse of fossils from this area have detailedly been described and discussed. Thus it is a significant new contribution on palaeontology and stratigraphy of the Upper Sinian in the west part of the Yangtze Platform.Ch.l Lithostratigraphy36 stratigraphical sections of the Upper Sinian have been described and cited. Inclouding 10 new measured sections. 16 reviewed sections and 4 cited sections. Based on the features of development, distribution, petrology and facies of strata, the Upper Sinian in this area can be further subdivided into secondary stratigraphical regions. In the subdivision of lithostratigraphical units, I reconsider the previous scenarios, and conclude that the lithostratigraphical units: Dengying Formation, Doushantuo Formation, Guanyin'ai Formation and Yangshui Formation are still valid and regard all other units of formation-grade as synonyms that thus should be abandoned. I also define each unit of formations and members, including characters of petrology and regional distribution. Finally, correlation between rock units of the Upper Sinian in different stratigraphical regions has been made and the stratigraphical framework has been constructed based on consistencies of petrology, facies and the relationships of rock units.Ch.2 BiostratigraphyFeatures, distribution and assemblage of seven group fossils from many of the 26 geological sections, including acritarch, macralgae, soft-bodied metazoans, spherical fossils, small shelly fossils and trace fossils, have been comprehensively discussed. And a series of fossil assemblages and biozones can be recognized. Finally, integrative correlation has been made.1) Acritarch assemblages:Assemblage IISubassemblage II -2(lower part of the Qiongzhusi Formation)Subassemblage II -2(the top of the Dengying Formation)Assemblage I Subassemblage I -4(lower and middle part of the DengyingFormation) Subassemblage I -3(upper part of the Doushantuo Formation) Subassemblage I -2(middle part of the Doushantuo Formation) Subassemblage I -1 (lower part of the Doushantuo Formation)2) Macroalgae assemblagesAssemblage II : Tyrasotaenia-Vendotaenia(Shibanian. Member, DengyingFormation)Assemblage I : Doushantuophyton-Gracilogia-Miaohenalla-Palaeocodium(At the top of Doushantuo Formation)3) Biozones of Small Shelly Fossils Meishucunstage:III: Lapworthella-Tannullolina-Sinosachites zone(Lower part of Qiongzhusi Form.)II : Paragloborilus-Siphogonuchites-Heraultipegma zone(Upper part ofZhongyichun Meb.) I : Anabarites trisulcatus-Protohertzina anabarica zone (Lower part ofZhongyichun Meb.) Doushantuocun stage: Sinocyclocyclicus-Sinoqudraticus zone(Upper Member, Doushantuo Formation)4) Globular fossilsIII: Archaeooides granulatus-Olivooides pearlforms Assamblage (Lower partof Qiongzhusi Formation) II: Archaeooides kuanchuanpuensis-Olivooides multisulcatus Assemblage(Kuanchuanpu Member, Dengying Formation)I : Archaeooides tuberculatus-Megaclonophycus-Parapandorina Assemblage (Upper Member, Doushantuo Formation)5) Soft-bodied metazoansIII: Cloudina-Sinotubulites-Qinella Assamblage (Baimatuo Melnber, DengyinForm.) II: Charnia dengyingensis-Gaojiashania cyclus Assamblage (Shibantan Meb.,Dengying Form.) I : Xiiinxiaella-Sanxiamedusa Assamblage (The top of Doushantuo Form.)6) Trace fossilsV: Rusophycus-Didymaulichnus Assamblage zone (Zhongyicun Member,Dengying Form.) IV: Chondrites-Helminitoida Assamblage zone (Baimatuo Member, DengyingForm.)III : Dengyingella-Tunisichnus Assamblage zone (Shibantan Member,Dengying Form.) II: Skolithos-Codonichnus Assamblage zone (Hamojing Member, DengyingForm.) I : Planotaenichnus-Linbotulichnus Assamblae zone...