Development of a High-Resolution Stromatolite Facies Model: Environmental Impacts at the Dawn of Oxygenation

高分辨率叠层石相模型的开发：氧化初期的环境影响

• 批准号: 1251422
• 负责人: Russell Shapiro
• 金额: $ 5.91万
• 依托单位: Chico State Enterprises
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1251422&HistoricalAwards=false
• 关键词: Development; Resolution; Stromatolite; Facies; Model

Development of a High-Resolution Stromatolite Facies Model: Environmental Impacts at the Dawn of OxygenationRussell ShapiroCalifornia State University, Chico StateThe Paleoproterozoic iron-bearing formations of the Animikie Basin host some of the best-preserved microfossils and diverse stromatolites from a time when the Earth was switching from anoxic to euxinic oceans. This interval, known as the "Great Oxidation Event," is an increasingly important research area for paleobiologists, geochemists, and economic geologists. However, important questions still exist as to the paleoenvironmental setting of the stromatolitic deposits, limiting the understanding of the complex interplay between oceanic conditions and the localized bacterial ecosystems. This proposal addresses how stromatolites vary in space in response to changing oceanographic and environmental conditions by applying powerful 3-D modeling software (Petrel v.2010) to an extraordinary collection of proprietary drill core. Specifically, this proposal addresses: (1) To what extent can the stromatolites be used to delineate shoreline geomorphology, enhancing paleoenvironmental reconstructions? and (2) What is the role of taphonomy in both stromatolite and microfossil preservation?Four major stromatolite types are found in roughly two, meter-scale horizons throughout the Animikie Basin, though not necessarily as continuous horizons. Mapping of open taconite mine walls (now flooded) demonstrated that macrostructural variability appears at scales of 10 to 100 meters. The stromatolites are biogenic and formed under normal marine conditions, above the chemocline, in suboxic waters. Based on this work, it is believed that the macrostructural forms of stromatolites, together with the sparse but well-preserved microfossil record, can be integrated with the sedimentologic and stratigraphic data to develop a model of stromatolite biofaces that will help to constrain the unique oceanographic variability in this critical interval of Earth history. The proposed research project will address stromatolite variation and the paleoenvironmental tectonic implications at a spatial resolution that has not been achieved in previous studies of this interval.Broader Impacts. The results of this project will be valuable to researchers studying paleontological and biogeochemical patterns in other pre-Cambrian basins during the "Great Oxidation Event." The dissemination plan calls for the development of a series of YouTube short films that will open up the dynamic and complex world of microbial-sediment interactions of the early oxygenated Earth to a broad audience. The research will provide critical primary research experience for several undergraduate students at a primarily undergraduate institution. The teaching methods of the PI will be enhanced with a greater understanding of this critical interval and opportunities for project-based learning which form an integral component of his pedagogy.

高分辨率叠层石相模式的发展：氧化黎明时的环境影响Russell Shapiro加利福尼亚州立大学，奇科州阿尼基盆地的古元古代含铁地层中含有一些保存最完好的微化石和不同的叠层石，这些化石和叠层石来自地球从缺氧海洋转换到缺氧海洋的时期。这段时间被称为“大氧化事件”，是古生物学家、地球化学家和经济地质学家日益重要的研究领域。然而，重要的问题仍然存在的叠层石矿床的古环境背景，限制了海洋条件和本地化的细菌生态系统之间的复杂的相互作用的理解。该提案通过将功能强大的三维建模软件（Petrel v.2010）应用于专有岩心的非凡收集，解决了层积物在空间中如何变化以应对不断变化的海洋和环境条件。具体而言，该建议涉及：（1）在何种程度上可以使用叠层石来描绘海岸线地貌，加强古环境重建？埋藏学在叠层石和微体化石保存中的作用是什么？四个主要的叠层石类型被发现在大约两个，米级的地平线在整个阿尼米奇盆地，虽然不一定是连续的地平线。对开放的铁合欢岩矿壁（现已被淹没）的测绘表明，宏观结构的变化出现在10至100米的尺度上。叠层石是生物成因的，在正常的海洋条件下，在化学跃层之上，在亚氧沃茨中形成。基于这项工作，它被认为是宏观结构形式的叠层石，连同稀疏但保存完好的微体化石记录，可以与沉积学和地层学数据相结合，开发一个模型的叠层石生物相，这将有助于限制独特的海洋变化，在这个关键的地球历史时期。拟议的研究项目将解决叠层石的变化和古环境构造的影响，在空间分辨率，还没有实现在以前的研究这一间隔。该研究成果对研究前寒武纪盆地“大氧化事件”期间的古生物和古地球化学模式具有一定的参考价值。“传播计划要求制作一系列YouTube短片，向广大观众展示早期含氧地球微生物-沉积物相互作用的动态和复杂世界。这项研究将为主要本科院校的几名本科生提供关键的主要研究经验。PI的教学方法将通过更好地理解这一关键间隔和基于项目的学习机会来加强，这是他教学法的一个组成部分。