Redox Chemistry and Molybdenum Burial in a Mesoproterozoic Lake
Redox Chemistry and Molybdenum Burial in a Mesoproterozoic Lake
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中元古代湖泊中的氧化还原化学和钼埋藏
DOI：
10.1029/2019gl083316
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发表时间：
2019
影响因子：
5.2
通讯作者：
A. Chappaz
中科院分区：
文献类型：
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作者：
K. Rico;N. Sheldon;T. Gallagher;A. Chappaz
虽然海洋沉积物已被用来限制整个前寒武纪的氧化还原化学的历史，少得多的数据已经从湖泊中产生。随着主要的生物学创新被认为发生在元古代湖泊中，了解它们的化学性质对于了解真核生物的进化至关重要。我们使用沉积物地球化学特征的Nonesuch形成（~1.1 Ga）和现代类似物的元古代的氧化还原条件：中岛天坑休伦湖（美国）。铁的形态，钼含量和钼-铀协变证明了好氧和缺氧的环境，没有明确的指标，提高生物生产力的Nonesuch形成。中等Mo富集Nonesuch形成中观察到的不归因于euxinia，而是一个自生微粒穿梭。我们认为，这些湖泊系统的铁和钼沉积物地球化学只反映当地的水柱和沉积物埋藏条件，而不是大气氧化。
While marine sediments have been used to constrain a history of redox chemistry throughout the Precambrian, far fewer data have been generated from lakes. With major biological innovations thought to have occurred in Proterozoic lakes, understanding their chemistry is critical for understanding the evolution of eukaryotic life. We use sediment geochemistry to characterize the redox conditions of the Nonesuch Formation (~1.1 Ga) and a modern analogue for the Proterozoic: the Middle Island Sinkhole in Lake Huron (USA). Iron speciation, Mo contents, and Mo‐U covariation demonstrate oxic and anoxic—not euxinic—environments, with no clear indicators of enhanced biological productivity in the Nonesuch Formation. Moderate Mo enrichments observed in the Nonesuch Formation are not attributed to euxinia, but instead to an authigenic particulate shuttle. We suggest that the Fe and Mo sediment geochemistry of these lacustrine systems reflect only local water column and sediment burial conditions and not atmospheric oxygenation.
DOI：
10.1073/pnas.1813493115
发表时间：
2018-12
期刊：
Proceedings of the National Academy of Sciences
影响因子：
--
作者：
S. Slotznick;N. Swanson‐Hysell;E. Sperling
通讯作者：
S. Slotznick;N. Swanson‐Hysell;E. Sperling