A new look at saponite formation and its implications for early animal records in the Ediacaran of South China
A new look at saponite formation and its implications for early animal records in the Ediacaran of South China
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皂石形成的新视角及其对华南埃迪卡拉早期动物记录的影响
DOI：
10.1111/gbi.12018
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发表时间：
2013-01
期刊：
影响因子：
3.7
通讯作者：
Hanjie Wen
中科院分区：
文献类型：
--
作者：
Xuelei Chu;TW Lyons;NJ Planavsky;Hanjie Wen
在长江三峡地区陡山沱组下部首次发现了一批类形疑源类化石，其中一些被认为是最早的动物胚胎化石。此外，YGA完整的古生物学和地球化学记录在确定全球生物和地球化学背景方面发挥了核心作用，这些背景预示并见证了多样化动物生命的黎明。尽管YGA在我们理解新元古代地球历史中的重要性，但关于其沉积历史的基本方面仍然存在争议。在这些争议中，最重要的是，YGA中被广泛研究的部分最近与碱性湖泊中的沉积有关，这对早期动物进化的环境以及YGA地球化学记录的更广泛意义产生了新的但有争议的影响。湖泊环境的论点取决于三八面体粘土（皂石-柯伦石）的存在。然而，这种粘土类型通常在其他环境中形成，包括镁铁质和超镁铁质火山岩的风化剖面。利用地球化学和沉积学的耦合方法，我们认为，在下陡山沱的YGA的三八面体粘土更好地解释为风化产物从区域镁铁质-超镁铁质腹地由河流输送到陆棚或泻湖在长江三峡盆地。YGA沉积物和相关粘土的这些新的物源关系与早期动物记录的海洋环境是一致的，必须考虑到我们目前对陡山沱组更广泛的地球化学结构的理解。
Acanthomorphic acritarch fossils, including some interpreted to be the fossils of the earliest animal embryos, first appear in the lower Doushantuo Formation of the Yangtze Gorges area (YGA). Further, the complete paleontological and geochemical record for the YGA has played a central role in defining the global biological and geochemical backdrop that presaged and witnessed the dawn of diverse animal life. Despite the importance of the YGA in our understanding of Neoproterozoic Earth history, basic aspects about its depositional history remain debated. Foremost among the controversies, extensively studied sections in the YGA were recently tied to deposition in an alkaline lake, casting new but contentious light on the environments of early animal evolution and the broader significance of geochemical records from the YGA. Arguments for a lacustrine setting hinged on the presence of trioctahedral clays (saponite–corrensite). However, this clay type commonly forms in other environments, including the weathering profiles of mafic and ultramafic volcanics. Using a coupled geochemical and sedimentological approach, we argue that the trioctahedral clays in the lower Doushantuo of the YGA are better explained as weathering products from a regional mafic‐to‐ultramafic hinterland delivered by rivers to a shelf or lagoon in the Yangtze Gorges Basin. These novel provenance relationships for YGA sediments and associated clays are consistent with a marine setting for the early animal records and must factor in our current understanding of the broader geochemical fabric of the Doushantuo Formation.
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影响因子：
4.2
作者：
Wilma W. Smith
通讯作者：
Wilma W. Smith
影响因子：
4.9
作者：
Xuan‐Ce Wang;Xian‐Hua Li;Wu-Xian Li;Zheng‐Xiang Li;Y. Liu;Yue-heng Yang;Xi-rong Liang;X. Tu
通讯作者：
Xuan‐Ce Wang;Xian‐Hua Li;Wu-Xian Li;Zheng‐Xiang Li;Y. Liu;Yue-heng Yang;Xi-rong Liang;X. Tu
DOI：
10.1073/pnas.0902322106
发表时间：
2009-04
期刊：
Proceedings of the National Academy of Sciences
影响因子：
--
作者：
Phoebe A. Cohen;A. Knoll;R. Kodner
通讯作者：
Phoebe A. Cohen;A. Knoll;R. Kodner
DOI：
10.1002/9781118666289
发表时间：
2004
期刊：
--
影响因子：
--
作者：
A. Ridgwell;M. Kennedy
通讯作者：
A. Ridgwell;M. Kennedy
DOI：
10.1007/978-3-540-75634-7
发表时间：
2008-08
期刊：
--
影响因子：
--
作者：
B. Velde;A. Meunier
通讯作者：
B. Velde;A. Meunier