埃迪卡拉紀，又稱艾迪卡拉紀、震旦紀、文德紀，是元古宙最後的一段時期，其後緊接著便是顯生宙的開端古生代的寒武紀。埃迪卡拉紀一般指 635541 億年前。學者曾用這個名字指稱不同階段，直到 2004 年 5 月 13 日，國際地質科學聯盟明確定義其年代，這是這個組織 120 年來首次對其加時期定義。最古老的動物遺跡可追溯至十億年前，但最早的動物化石出現於埃迪卡拉紀。 埃迪卡拉紀和震旦紀、文德紀 埃迪卡拉生物群因為發現於南澳洲的而得名。1946 年，一位澳洲地質學家在古代的沙岩板中留意到一曾在這裡發現顯生宙以前的化石。研究這些化石的科學家認為這是珊瑚、水母和蠕蟲的先驅。以後幾十年，南澳洲還找到很多的隱生宙化石，其他各大洲也找到一些。這些化石都叫作埃迪卡拉動物。一開始，人們認為埃迪卡拉動物是寒武紀的動物，但經過仔細的觀察，埃迪卡拉生物群比寒武紀還久遠，應屬於埃迪卡拉紀。 本紀曾被一些人稱為震旦紀（Sinian）見大英百科全書條目。震旦紀的名稱來源於中國，震旦 是中國的古稱。由於古印度人稱中國為 Cinisthana，在佛經中被譯為震旦，故名震旦紀。時至今日，中國學者仍經常這麼稱呼，中國教科書上一直稱此紀為震旦紀。俄國人又把埃迪卡拉紀稱為文德紀（Vendian），他們在這一時期的地層中又發現了一些古線蟲動物的化石。 上下邊界 縮圖 標誌著 GSSP 的 金穗 細分 絕對年代 生物群 埃迪卡拉生物群是 1946 年發現於南澳洲的末遠古系龐德石英岩中的化石群，這類化石群已在世界 30 多個地點被發現。它們是迄今已知最早的複雜多細胞生物。Wang W Guan C Hu Y et alSpatial and temporal evolution of Ediacaran carbon and sulfur cycles in the Lower Yangtze Block South China JPalaeogeography Palaeoclimatology Palaeoecology 2019 537109417DOI101016jpalaeo2019109417 簡單多細胞生物，如紅藻，在最晚 12 億年前已進化形成。 埃迪卡拉動物和今天的大多數動物截然不同，牠們既沒頭、尾、四肢，也無口部和消化器官，因此牠們大概只能從水中攝取養份。大多的埃迪卡拉動物固著在海底，和植物十分相近，其他的則平躺在淺海處，等待營養順水流而送上門來。埃迪卡拉動物化石出土越多，反而越沒有規律。有一些化石比較像後來動物的先驅。 在埃迪卡拉紀末期，埃迪卡拉動物分成兩支，牠們有的成功演化成更有活力，更具進攻性的動物，並在之後的寒武紀大爆發中大放異彩，成為現今大多數動物門的祖先。而有的則走向滅亡，牠們的特徵也永遠消失於歷史舞臺上。 天文因素 參見 埃迪卡拉紀末期滅絕事件 參考資料 腳註 書目 A Knoll M Walter G Narbonne and N ChristieBlick 2004 The Ediacaran Period A New Addition to the Geologic Time Scale Submitted on Behalf of the Terminal Proterozoic Subcommission of the International Commission on Stratigraphy Knoll A H Walter MR Narbonne G M ChristieBlick N 2004 A new period for the geologic time scale Science 305 5684 621622 Knoll A H Walter M R Narbonne G M and ChristieBlick N 2006 The Ediacaran Period A new addition to the geologic time scale Lethaia 39 1330 Geological time gets a new period Geologists have added a new period to their official calendar of Earths historythe first in 120 years London BBC 20040517 Accessed 27 December 2010 South Australian Museum Newsletter April 2005 Accessed 9 August 2010 B M Sokolov 1952 On the age of the old sedimentary cover of the Russian Platform Izvestiya Akademii Nauk SSSR Seriya eologicheskaya 5 2131 Sokolov BS 1997 Essays on the Advent of the Vendian System 153 pp KMK Scientific Press Moscow in Russian Sokolov B S 1965 Abstracts of AllUnion Symposium on Paleontology of the Precambrian and Early Cambrian Nauka Novosibirsk Rozanov AY Missarzhevskij VV Volkova NA Voronova LG Krylov IN Keller BM Korolyuk IK Lendzion K Michniak R Pykhova NG and Sidorov AD 1969 The Tommotian Stage and the problem of the lower boundary of the Cambrian Trudy Geologičeskogo Instituta AN SSSR 206 1380 M A Fedonkin B S Sokolov M A Semikhatov N M Chumakov 2007 Vendian versus Ediacaran priorities contents prospectives In The Rise and Fall of the Vendian Ediacaran Biota Origin of the Modern Biosphere Transactions of the International Conference on the IGCP Project 493n Moscow GEOS August 2031 2007 Khomentovsky V V 2008 The Yudomian of Siberia Vendian and Ediacaran systems of the International stratigraphic scale Stratigraphy and Geological Correlation 16 6 581598 Comments By B S Sokolov M A Semikhatov And M A Fedonkin 2004 Appendix 2 in The Ediacaran Period A New Addition to the Geologic Time Scale Submitted on Behalf of the Terminal Proterozoic Subcommission of the International Commission on Stratigraphy pp 3234 Bristow T F and Kennedy M J 2008 Carbon isotope excursions and the oxidant budget of the Ediacaran atmosphere and ocean Geology 36 11 863866 Retrieved 20070505 Le Guerroué E Allen P A Cozzi A 2006 Chemostratigraphic and sedimentological framework of the largest negative carbon isotopic excursion in Earth history The Neoproterozoic Shuram Formation Nafun Group Oman Precambrian Research 146 12 6892 Le Guerroué E Allen P A Cozzi A Etienne J L and Fanning C M 2006 50 Myr recovery from the largest negative δ13C excursion in the Ediacaran ocean Terra Nova 18 2 147153 Le Guerroué E Allen P A Cozzi A 2006 Parasequence development in the Ediacaran Shuram Formation Nafun Group Oman primary origin stratigraphic test of negative carbon isotopic ratios Basin Research 18 2 205220 A Ragozina D Dorjnamjaa A Krayushkin E Serezhnikova 2008 Treptichnus pedum and the VendianCambrian boundary 33 Intern Geol Congr August 614 2008 Oslo Norway Abstracts Section HPF 07 Rise and fall of the Ediacaran Vendian biota P 183 Hoffmann KH Condon DJ Bowring SA Crowley JL 20040901 UPb zircon date from the Neoproterozoic Ghaub Formation Namibia Constraints on Marinoan glaciation Geology 32 9 817820 Condon D Zhu M Bowring S Wang W Yang A and Jin Y 1 April 2005 UPb Ages from the Neoproterozoic Doushantuo Formation China abstract Science 308 5718 9598 Calver CR Black Lance P Everard John L Seymour David B 20041001 UPb zircon age constraints on late Neoproterozoic glaciation in Tasmania Geology 32 10 893896 Ogg J G 2004 Status of Divisions of the International Geologic Time Scale Lethaia 37 2 183199 Amthor J E Grotzinger John P Schröder Stefan Bowring Samuel A Ramezani Jahandar Martin Mark W Matter Albert 2003 Extinction of Cloudina and Namacalathus at the PrecambrianCambrian boundary in Oman Geology 31 pp 431434 Earliest Animal Footprints Ever Found Discovered in Nevada Newswise Retrieved on October 5 2008 Reporting on a poster session at the Geological Society of America 紀 分類：新元古代