Oceanic oxygenation events in the anoxic Ediacaran ocean
Oceanic oxygenation events in the anoxic Ediacaran ocean
复制标题
DOI：
10.1111/gbi.12182
复制
发表时间：
2016-09-01
期刊：
影响因子：
3.7
通讯作者：
Lyons, T. W.
中科院分区：
文献类型：
--
作者：
Sahoo, S. K.;Planavsky, N. J.;Lyons, T. W.
海洋-大气系统通常被设想为经历了单向氧化，在最早期（约2000年）氧气显著增加。635Ma），中部（ca. 580Ma），或晚（ca. 560Ma）埃迪卡拉纪。然而，时间上不连续的地球化学数据和零散的后生动物化石记录不足以描绘埃迪卡拉纪海洋氧合的细节，引起了关于海洋氧合时间的根本性争论，其所谓的单向上升，以及其因果关系，如果有的话，与早期动物生命的进化。为了更好地了解埃迪卡拉纪海洋氧化还原的演变，我们进行了多代理古氧化还原研究的一个相对连续的，在中国南方的深水部分，是古地理连接到开放的海洋。铁的形态和黄铁矿的形态表明局部缺氧（缺氧和硫化物）的环境在整个埃迪卡拉纪在这一节。在同一岩石中，氧化还原敏感元素富集和硫同位素数据提供了证据，在一个主要是缺氧的全球埃迪卡拉-早寒武世海洋的多个海洋氧化事件（OOEs）。这种动态的氧化还原景观对比与最近的看法氧化还原静态埃迪卡拉海洋没有显着变化的氧含量。埃迪卡拉OOE的持续时间可能是可比的海洋缺氧事件（OAE），否则良好的氧合的中生代海洋。在生物多样性丰富的古生代海洋中，缺氧事件导致大规模的生物灭绝，随后又迅速恢复。相比之下，氧化事件，否则生态单调缺氧埃迪卡拉-早寒武纪海洋可能刺激生物的创新，随后长期的进化停滞。
The ocean-atmosphere system is typically envisioned to have gone through a unidirectional oxygenation with significant oxygen increases in the earliest (ca. 635Ma), middle (ca. 580Ma), or late (ca. 560Ma) Ediacaran Period. However, temporally discontinuous geochemical data and the patchy metazoan fossil record have been inadequate to chart the details of Ediacaran ocean oxygenation, raising fundamental debates about the timing of ocean oxygenation, its purported unidirectional rise, and its causal relationship, if any, with the evolution of early animal life. To better understand the Ediacaran ocean redox evolution, we have conducted a multi-proxy paleoredox study of a relatively continuous, deep-water section in South China that was paleogeographically connected with the open ocean. Iron speciation and pyrite morphology indicate locally euxinic (anoxic and sulfidic) environments throughout the Ediacaran in this section. In the same rocks, redox sensitive element enrichments and sulfur isotope data provide evidence for multiple oceanic oxygenation events (OOEs) in a predominantly anoxic global Ediacaran-early Cambrian ocean. This dynamic redox landscape contrasts with a recent view of a redox-static Ediacaran ocean without significant change in oxygen content. The duration of the Ediacaran OOEs may be comparable to those of the oceanic anoxic events (OAEs) in otherwise well-oxygenated Phanerozoic oceans. Anoxic events caused mass extinctions followed by fast recovery in biologically diversified Phanerozoic oceans. In contrast, oxygenation events in otherwise ecologically monotonous anoxic Ediacaran-early Cambrian oceans may have stimulated biotic innovations followed by prolonged evolutionary stasis.