橫跨近一億年之久的埃迪卡拉紀 (Ediacaran),結束於古生代初期(Paleozoic Era) (邁向寒武紀)。 在埃迪卡拉紀之前的成冰紀 (Cryogenian),地球大部分的面積被冰川所覆蓋住,所以氣候相當的寒冷,不過當埃迪卡拉紀來臨時,氣候轉為溫和。這段時期有時候也被稱為文德期 (Vendian Period)。按照國際地層委員會 (The International Commission on Stratigraphy) 所制定的地質年代表,埃迪卡拉紀的年代是在6億3500萬至5億4200萬年前。
在埃迪卡拉紀時期所發現的動物化石,其年代約有6億至5億4500萬年或5億5500萬年之久(有些網路資料對埃迪卡拉紀的開始年代,有很多不同的記載,日期的誤差很大,把埃迪卡拉紀的日期混淆到新元古代 (Neoproterozoic Era) 或元古宙 (Proterozoic Eon) 的日期。)
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相關連結
1. David Morrison’s 2004 essay about the measure of deep time at NASA.
2. A page (mostly by Chris Clowes) at the Palaeos website describing the Ediacaran Era.
3. A description of the Ediacara Biota from The Miller Museum.
4. Some displays of life from the Ediacaran Era from The Dinosaur Collector.
5. There is some confusion about just what was alive in the Ediacaran Era. The University of California at Berkeley mentions this, and an old (1990) article from New Scientist by Simon Conway Morris offers some questions about early life (although most of the article is about the Burgess Shale, which represents a time after the end of the Ediacaran Era).