Palaeoproterozoic 全球冻结成冰(2.3 Ga ) 可以是地球历史上的第一个雪球地球事件。诺思中国暴露得好沉积存款这次有最小的 postdepositional 的时期改变。一个冻结成冰事件的沉积证据然而一直在缺乏。这里,我们在 Wutai 山区分析了 Paleoproterozoic Hutuo 组(2.52.2 Ga ) 的碳同位素作文,山西省,诺思中国。我们的数据表演,在里面一对更年轻的 chronostratigraphic 顺序更旧,(1 ) 积极 13Ccarb 在 Doucun 亚群的 Dashiling 形成珍视(3.2 ~ 1.0, VPDB ) ;(2 ) 在 13Ccarb 的减少从 Wenshan 形成珍视到中间的 Daguandong 形成(从 2.0 to1.2 ) ,在哪个时间期间 stromatolites 的出现衰退了;(3 ) 在上面的 Daguandong 形成的一次显著否定旅行,在 Daguandong 和 Huaiyincun 形成的边界(从 1.4 ~ 3.3 ) ,在 stromatolites 消失了的地方;并且(4 ) 13Ccarb 的渐渐的增加在 Beidaxing 和 Tianpengnao 形成珍视(从 1.2 ~ 1.4 ) ,在哪个期间时间 stromatolites 回来了。我们主张否定的碳同位素旅行从 Jianancun 形成记录了到 Hutuo 组的中间的 Daguandong 形成可以是对 Palaeoproterozoic 全球冻结成冰的诺思瓷器反应。
Palaeoproterozoic global glaciation (~2.3 Ga) may have been the first "snowball" Earth event in Earth history. North China has well-exposed sedimentary deposits of this time period with minimal postdepositional alteration. Sedimentary evidence of a glaciation event has been lacking, however. Here we analyzed carbon isotope composition of the Paleoproterozoic Hutuo Group (2.5-2.2 Ga) in the Wutai Mountain area, Shanxi Province, North China. Our data show, in an older to younger chronostratigraphic order, (1) positive δ 13 C carb values in the Dashiling Formation of the Doucun Subgroup (3.2‰ to 1.0‰, VPDB); (2) a decrease in δ 13 C carb values from the Wenshan Formation to the middle Daguandong Formation (from 2.0‰ to 1.2‰), during which time the occurrence of stromatolites declined; (3) a pronounced negative excursion in the upper Daguandong Formation, at the boundary of the Daguandong and Huaiyincun formations (from 1.4‰ to 3.3‰), where stromatolites disappeared; and (4) a gradual increase of δ 13 C carb values in the Beidaxing and Tianpengnao formations (from 1.2‰ to 1.4‰), during which time stromatolites returned. We argue that the negative carbon isotope excursion recorded from the Jian'ancun Formation to the middle Daguandong Formation of the Hutuo Group may have been North China's response to the Palaeoproterozoic global glaciation.