A growing number of detailed geochemical studies of Ediacaran (635–541 Ma) marine successions have provided snapshots into the redox environments that played host to the earliest known metazoans. Whilst previous compilations have focused on the global evolution of Ediacaran water column redox chemistry, the inherent heterogeneity evident in palaeogeographically distinct environments demands a more dissected approach to better understand the nature, interactions and evolution of extrinsic controls on the development of early macrobenthic ecosystems. Here, we review available data of local‐scale redox conditions within a palaeogeographic and sequence stratigraphic framework, to explore the mechanisms controlling water column redox conditions and their potential impact on the record of metazoans. The openly connected Laurentian margin, North America (632–540 Ma) and Nama basin, Namibia (550–538 Ma), and the variably restricted Yangtze Block, South China (635–520 Ma), show continued redox instability after the first fossil evidence for metazoans. This may support opportunistic benthic colonisation during periods of transient oxygenation amidst episodic upwelling of anoxic waters beneath a very shallow, fluctuating chemocline. The first skeletal metazoans appeared under conditions of continued redox stratification, such as those which characterise the Dengying Formation of the Yangtze Block and the Kuibis Subgroup of the Nama basin. Current data, however, suggests that successful metazoan reef‐building demanded more persistent oxia. We propose that cratonic positioning and migration throughout the Ediacaran Period, in combination with gradually increasing dissolved oxygen loading, may have provided a first‐order control on redox evolution through regulating circulation mechanisms in the Mirovian Ocean. Some unrestricted lower slope environments from mid‐high latitudes benefited from sustained oxygenation via downwelling, whilst transit of isolated cratons towards more equatorial positions stifled pervasive ventilation either through ineffective surface ocean mixing, Ekman‐induced upwelling, elevated surface ocean productivity or a combination of these processes.

中文翻译：

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Ediacaran后生动物生态系统演变的控制：氧化还原的观点。

越来越多的关于Ediacaran（635-541 Ma）海洋演替的详细地球化学研究提供了有关氧化还原环境的快照，这些环境是最早的已知后生动物的寄主。尽管先前的编辑集中在埃迪卡拉安水柱氧化还原化学的全球发展过程中，但在古地理上不同的环境中显而易见的固有异质性要求采用更解剖的方法，以便更好地了解外部控制对于早期大型底栖生态系统发展的性质，相互作用和演化。在这里，我们回顾了古地理和层序地层学框架内当地规模氧化还原条件的可用数据，以探讨控制水柱氧化还原条件的机制及其对后生动物记录的潜在影响。劳伦式边缘的公开连接，北美（632-540 Ma）和纳米比亚的纳马盆地（550-538 Ma），以及华南地区受限制的扬子地带（635-520 Ma），在首次获得后生动物化石证据后，仍表现出持续的氧化还原不稳定。这可能支持在一个非常浅的，波动的趋化线之下的缺氧水的间歇性上升过程中，在短暂的氧合作用期间的机会性底栖生物定殖。第一个骨骼后生动物出现在持续的氧化还原分层条件下，例如那些代表了纳马盆地扬子地块和奎比斯亚群的灯影组的特征。然而，目前的数据表明，成功的后生动物礁建设需要更持久的氧气。我们建议在整个Ediacaran时期进行克拉通定位和迁移，并结合逐渐增加的溶解氧负荷，通过调节米罗维亚海洋中的环流机制，可能对氧化还原的演化提供了一级控制。一些来自中高纬度的不受限制的低坡度环境得益于下降带来的持续充氧作用，而孤立的克拉通向赤道位置的过渡通过无效的表层海洋混合，埃克曼引起的上升流，上升的表层海洋生产力或这些因素的组合，抑制了普遍的通风。流程。