Microfossils: a tool for dating and reconstructing paleoenvironmental changes and biological evolution

微化石：测定和重建古环境变化和生物进化的工具

• 批准号: 346191-2007
• 负责人: Herrle, JensOlaf
• 金额: $ 1.72万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=400403
• 关键词: Microfossils; tool; dating; reconstructing; paleoenvironmental

The objective of this research program is to exploit the unique potential of microfossils for reconstructing past environmental and evolutionary changes during major perturbations to the Earth system. The main focus is to assess the causes and consequences of periods of massive burial of marine organic carbon during the Mesozoic. These intervals, known as Oceanic Anoxic Events (OAEs), represent the main source rock of hydrocarbons that are exploited today. Central to the proposed research is the investigation of the four most prominent OAEs of the Mesozoic (Toarcian OAE and Cretaceous OAE1, 2, and 3). These events are associated with pronounced carbon isotope excursions of >1.5 per mille and elevated rates of biotic extinction and speciation indicating a broad impact on the evolution of Earth's ocean, climate, and biotic system. These OAEs will be studied in a mid- to high-latitude transect from the Canadian Western Interior Seaway (CWIS) to the Atlantic Ocean. These areas hold great potential to shed new light on the formation of OAEs because high latitude regions are so important for controlling the global ocean-atmospheric circulation system. A high resolution bio- and chemostratigraphy will be established, that allows the precise stratigraphic correlation between high and low latitudes sections, which are of utmost importance for the understanding of the processes, the timing, and the spatial extension of OAE formation. Furthermore, well established and new indicators for environmental changes (e.g., productivity) will be applied to reconstruct the paleoenvironmental conditions that led to OAEs. To develop new environmental indicators, the formation of organic rich sediments deposited in the Mediterranean Sea during the Holocene, the sapropel S1, will be analyzed. This sapropel may serve as an ideal example of how anoxic sediments have been formed and provides the potential to develop new paleontological indicators for the reconstruction of OAEs. Moreover, selected microfossil groups will be investigated to assess and quantify evolutionary changes connected with the formation of OAEs in a mid- to high latitudinal transect. This transect will allow to distinguish between evolutionary and ecological trends in microfossils through time.

这项研究计划的目标是利用微体化石的独特潜力，重建地球系统重大扰动期间过去的环境和进化变化。主要重点是评估中生代海洋有机碳大量埋藏时期的原因和后果。这些间隔被称为海洋缺氧事件（OAE），代表了当今开采的碳氢化合物的主要源岩。拟议研究的核心是调查中生代四个最突出的OAE（Toarcian OAE和白垩纪OAE 1，2和3）。这些事件与碳同位素的明显偏移（>1.5 ‰）以及生物灭绝和物种形成的速率升高有关，这表明对地球海洋，气候和生物系统的演变产生了广泛的影响。这些OAE将在从加拿大西部内陆航道（CWIS）到大西洋的中高纬度样带进行研究。这些地区具有巨大的潜力，为OAE的形成提供新的线索，因为高纬度地区对控制全球海洋-大气环流系统非常重要。将建立一个高分辨率的生物和化学地层学，允许高纬度和低纬度部分之间的精确地层对比，这对于理解OAE形成的过程，时间和空间扩展至关重要。此外，环境变化的既定指标和新指标（例如，生产力）将被应用于重建导致OAE的古环境条件。为了开发新的环境指标，将分析全新世期间沉积在地中海的富含有机物的沉积物的形成，腐泥S1。这腐泥可以作为一个理想的例子，缺氧沉积物是如何形成的，并提供了潜在的开发新的古生物学指标的OAE重建。此外，选定的微体化石群将进行调查，以评估和量化的进化变化与形成的OAE在中高纬度样带。该样带将允许区分微化石随时间的进化和生态趋势。