古太平洋淮南—小达尔生物地理区的初步确认及其意义——重建新元古代Rodinia超大陆的古生物学证据

The Tentative Establishment of Palaeopacific Huainan Litlle dal Biogeographic Demaration and its Significace——on the Palaeontological Evidence About Reestablishing Newproterozoic Rodinia Supercontinent

淮南生物群和小达尔生物群化石分别产于我国华北地台和北美劳伦古陆新元古代地层中。在我国华南地块、前苏联西伯利亚地台、南亚印度古陆、澳大利亚和北欧波罗的海地盾等都有发现。在今天的地理分布上 ,它们或远隔重洋 ,或处于欧亚大陆东西两端 ,然而它们为什么会有如此相同的化石组合和大体相同时代的地层层位呢 ?以前从事前寒武纪地层古生物研究的国内外学者很少探讨这一问题。近年来 ,国内外学者根据各大陆新元古代地层构造资料并参照古地磁学研究成果重建的新元古Rodinia超大陆似乎较好地回答了这一问题。笔者将淮南生物群和小达尔生物群化石在各大陆的分布同新元古超大陆Rodinia各古陆块相对位置对照研究后发现 :淮南—小达尔生物群主要分布在古太平洋海槽南北两侧 ,形成一个以淮南生物群和小达尔生物群为代表的生物地理区系。古太平洋淮南—小达尔生物地理区系的初步识别和确认 ,为重建新元古Rodinia超大陆提供了古生物学上的直接证据 ,具有地层学。

Huainan Biota, named by professor Zheng Winwu (郑文武, 1979), except for the abundant stromatolites, contains mainly magascopic algal fossils and worm(metazoan) fossils, as well as acritarchs in the Newproterozoic strata of North China Platform. There are 19 genera of magascopic algal fossils, including Chuaria, Shouhsienia, Morania?, Ovidiscina, Fuxiania,Bipatinella, Nephroformis, Linguiformis,Cylindraceusa, Pumilibaxa, Tachymacrus,Mesonactus,Glossophyton,Qinggouziella, Tawuia, Sinenia,Tyrasotaenia,Fasciculella, Longfengshania, and 10 genera of worm (metazoan) fossils,including Dickinsonia, Huainanella,Pararenicola, Protoarenicola, Huaiyuanella, Ruedemannella, Anhuiella, Paleorhynchus, Sabellidites, Paleolina in Huainan biota. Chuaria Tawuia assemblage of magascopic algal fossils was widely distributed from North China, South China, Baltica,Siberia, Laurentia, Australia, and India blocks, and Pararenicola Paleolina assemblage of worm(metazoan) fossils was only distributed from North China, Siberia and India blocks in Newproterozoic Rodinia Supercontinent(see fig.1). Rodinia was the supercontinent assembled in the global orogenic Grenvillian event at the close of Mesoproterozoic time, ca.1 000 Ma,and fragmented during the New proterozoic,ca. 750 Ma.In Newproterozoic Rodinia Supercontinent, there was a palaeosea basin named the Palaeopacific Ocean between North China, Siberia, South China, Australia, India blocks and Baltica, Laurentia,East Antactica blocks.Huainan Little Dal Biota was distributed along the both of northern and southern front of the Palaeopacific Ocean, forming the Palaeopacific Ocean Huainan Little Dal Biogeographic Demaration.The confirmation of the Palaeopacific Ocean Biogeographic Demaration in Newproterozoic Rodinia Supercontinent is of important significance not only in the subdivision and correlation of Newproterozoic strata but also in the reestablishing Newproterozoic Rodinia Supercontinent.