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

新元古代是地球系统发生巨大变化的时期，包括超大陆Rodinia的分裂，几个全球范围的“雪球地球”冰河时代，海水同位素组成的显着波动，以及海洋和大气中氧气水平的增加但波动。在新元古代全球变化的背景下，我们看到了生命进化中同样深刻的变化，埃迪卡拉纪晚期（5.71亿年前）出现了丰富的标本和多种大型和结构复杂的生命形式，经过30亿年的主要微生物进化。埃迪卡拉生物群是一个全球性的软体海洋生物组合，现在保存在砂岩或火山灰事件床下的化石印记，构成寒武纪丰富的贝壳化石和复杂洞穴的基础。埃迪卡拉纪的生命是埃迪卡拉纪末期没有存活下来的生物群（例如rangeomorphs）的混合物，以及在寒武纪爆发期间多样化的茎群动物，它们是我们现代世界所有动物生命的祖先。已知最古老的埃迪卡拉类化石是长达2米的类化石，它们出现在新列入联合国教科文组织世界遗产的错误点内的Drook组的上部;在英格兰中部和加拿大西北部也有广泛的同时代阿瓦隆组合。在接下来的五年里，我将评估埃迪卡拉全球变化和生物进化之间的相互关系，通过研究最古老的埃迪卡拉型化石在阿瓦隆纽芬兰，加拿大西北部和澳大利亚和一个综合延伸到整个世界范围内的时期。我们的实地研究是地层学，沉积学和古生物学，也将利用同位素和氧化还原地球化学的国际合作者。在纽芬兰，我们将分析一个极好的暴露的商场湾-Drook地层，以前只知道在一个侦察水平，早于大部分的Mistaken点的adenoferous继承，从而可以提供信息的环境条件，立即出现在阿瓦隆纽芬兰的生物复杂性。在加拿大西北部的工作将集中在深水Nadaleen组的化石，以加强数据集和解释最近的阿瓦隆组合延伸到劳伦。所有已知的阿瓦隆组合都来自深水环境。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，这些化石可能与Mistaken Point最年轻的化石同时代，将记录这些浅水碳酸盐环境的化石和环境条件。总的来说，这些研究将阐明埃迪卡拉纪全球变化背景下大规模和生物复杂性的早期发展，并将为2名博士，3名硕士和5名BSc HQP提供培训。

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.