Anoxia in the terrestrial environment during the late Mesoproterozoic
Anoxia in the terrestrial environment during the late Mesoproterozoic
复制标题
DOI：
10.1130/g34299.1
复制
发表时间：
2013-05-01
期刊：
影响因子：
5.8
通讯作者：
Selby, David
中科院分区：
文献类型：
--
作者：
Cumming, Vivien M.;Poulton, Simon W.;Selby, David
大量证据表明，在前寒武纪的大部分时间里，海洋环境基本上是缺氧的。与此相反，陆地水生环境的氧合历史很少受到关注，尽管这种设置的早期真核生物进化的意义。为了解决这一问题，我们在这里提供了一个地球化学和同位素评估的沉积物从晚中元古代北美中部的Nonesuch组。我们利用铼锇（Re-Os）地质年代学产生的沉积年龄为1078 +/- 24马，而Os同位素组成支持现有的证据，湖泊环境。Fe-S-C系统学表明，Nonesuch组沉积从缺氧富铁（含铁）水柱。因此，类似于海洋领域，缺氧持续在陆地水生环境中的中至晚元古代，但硫化物水柱条件并不普遍。我们的数据表明，陆地领域的氧合是不普遍的，在这个时候，可能没有之前的海洋环境的氧合，这意味着一个主要的要求，进一步调查之间的联系陆地水生环境和真核生物进化的氧合状态。
A significant body of evidence suggests that the marine environment remained largely anoxic throughout most of the Precambrian. In contrast, the oxygenation history of terrestrial aquatic environments has received little attention, despite the significance of such settings for early eukaryote evolution. To address this, we provide here a geochemical and isotopic assessment of sediments from the late Mesoproterozoic Nonesuch Formation of central North America. We utilize rhenium-osmium (Re-Os) geochronology to yield a depositional age of 1078 +/- 24 Ma, while Os isotope compositions support existing evidence for a lacustrine setting. Fe-S-C systematics suggest that the Nonesuch Formation was deposited from an anoxic Fe-rich (ferruginous) water column. Thus, similar to the marine realm, anoxia persisted in terrestrial aquatic environments in the Middle to Late Proterozoic, but sulfidic water column conditions were not ubiquitous. Our data suggest that oxygenation of the terrestrial realm was not pervasive at this time and may not have preceded oxygenation of the marine environment, signifying a major requirement for further investigation of links between the oxygenation state of terrestrial aquatic environments and eukaryote evolution.