proterozoic eon 中文意思是什麼
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Global ice ages occurred at least three times in the period known as the proterozoic eon, first at 2. 3 billion years ago and again at 750 million and 600 million years ago
原生代期間至少發生過三次全球性冰期,第一次始於23億年前,其後於7 . 5億與6億年前又再度發生。
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