When Life Got Big - Ediacaran evolution in a period of profound global change

当生命变大时——全球深刻变革时期的埃迪卡拉演化

• 批准号: RGPIN-2020-06741
• 负责人: Narbonne, Guy
• 金额: $ 2.62万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740593
• 关键词: When; Life; Got; Big; Ediacaran

The Neoproterozoic was a time of massive changes in the Earth System that included breakup of supercontinent Rodinia, several 'snowball Earth' ice ages of global extent, marked fluctuations in the isotopic composition of seawater, and increased but fluctuating levels of oxygen in the oceans and atmosphere. Against this backdrop of Neoproterozoic global change we see an equally profound change in the evolution of life, the late Ediacaran (571 million years ago) appearance of abundant specimens and multiple taxa of large and architecturally complex life-forms after three billion years of mostly microbial evolution. The Ediacara biota is a global assemblage of soft-bodied marine creatures, now preserved as fossil impressions under event beds of sandstone or volcanic ash, that underlie the abundant shelly fossils and complex burrows of the Cambrian. Ediacaran life was a mixture of biotic groups that did not survive the end of the Ediacaran Period (e.g. rangeomorphs), alongside stem-group animals that diversified during the Cambrian explosion and were the ancestors of all animal life in our modern world. The oldest Ediacara-type fossil impressions known anywhere are rangeomorph fossils up to 2 meters long that occur in the upper part of the Drook Formation within the newly inscribed Mistaken Point UNESCO World Heritage Site; broadly coeval Avalonian assemblages also occur in central England and NW Canada. Over the next five years, I will assess the inter-relationship between Ediacaran global change and biotic evolution through studies of the oldest Ediacara-type fossils in Avalonian Newfoundland, NW Canada, and Australia and a synthesis extending through the entire period worldwide. Our field studies are stratigraphic, sedimentological, and paleontological and will also utilize international collaborators in isotope and redox geochemistry. In Newfoundland we will analyse a superbly exposed succession of Mall Bay-Drook strata, previously known only at a reconnaissance level, that predate most of the fossiliferous succession at Mistaken Point and thus can provide information on environmental conditions that immediately preceded the appearance of biological complexity in Avalonian Newfoundland. Work in NW Canada will focus on fossils in the deep-water Nadaleen Formation to enhance the data set and interpretation of this recent extension of the Avalonian assemblage into Laurentia. All known occurrences of the Avalon assemblage are from deep-water settings. Our study of the Wonoka Formation, which contains sparse specimens of the oldest Ediacara-type fossils in Australia that may be coeval with the youngest fossils at Mistaken Point, will document the fossils and environmental conditions of these shallower-water carbonate environments. Collectively, these studies will elucidate the early development of large size and biological complexity in the context of Ediacaran global change and will provide training for 2 PhD, 3 MSc and 5 BSc HQP.

新元古代是地球系统发生巨大变化的时期，包括超大陆的罗迪尼亚分解，几个“雪地地球”冰量的全球范围，在海水的同位素组成中显着波动，并增加了海洋，海洋和海洋氧气水平的波动气氛。在这种新元古代全球变化的背景下，我们看到了生命的演变的同样深刻的变化，已故的Ediacaran（5.71亿年前）出现了丰富的标本和多个大型且建筑具有复杂生命形式的分类群，大多数是微生物。进化。 Ediacara Biota是柔软的海洋生物的全球组合，现已保存在砂岩或火山灰的事件床上，这是寒武纪的丰富的Shelly化石和复杂的洞穴的基础。 Ediacaran Life是生物群的混合物，这些群体在Ediacaran时期（例如rangeomorphs）结束时与寒武纪爆炸期间多样化的干型动物一起生存，并​​且是我们现代世界中所有动物生活的祖先。最古老的Ediacara型化石印象是任何地方都知道的是五型物质化石，长达2米长，是在新插入的错误点的UNESCO世界遗产遗址中发生的drook上部。广泛的加拿大阿瓦隆组合也发生在英格兰中部和加拿大西北。在接下来的五年中，我将通过研究Avalonian Newfoundland，NW Canada和Australia的最古老的Ediacara型化石以及整个全球范围内延伸的合成，评估Ediacaran全球变化与生物进化之间的关系。我们的现场研究是地层，沉积学和古生物学的，还将利用国际合作者在同位素和氧化还原地球化学中。在纽芬兰，我们将分析以前仅在侦察水平上闻名的购物中心湾 - 丁基阶层的揭示，该地层早于侦察级，该地层早于Mistaken Point的大多数化石继承，因此可以提供有关环境条件的信息，该环境条件立即出现了生物学复杂性的出现。在阿瓦隆纽芬兰。加拿大西北地区的工作将重点放在深水纳达琳（Nadaleen）地层中的化石上，以增强对阿瓦隆（Avalonian）组合延伸到劳伦蒂亚（Laurentia）的最新扩展的数据集和解释。 Avalon组合的所有已知事件均来自深水环境。我们对Wonoka组的研究，其中包含澳大利亚最古老的Ediacara型化石的稀疏标本，这些标本可能与Mistaken Point上最年轻的化石同时使用，它将记录这些较浅的含水碳酸盐环境的化石和环境条件。总的来说，这些研究将在Ediacaran全球变化的背景下阐明大小和生物学复杂性的早期发展，并将为2博士学位，3 MSC和5 BSC HQP提供培训。