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

这一研究计划的目的是开发微化石的独特潜力，以重建地球系统遭受重大扰动时过去的环境和进化变化。主要重点是评估中生代期间大量埋藏海洋有机碳的原因和后果。这些间隔被称为海洋缺氧事件(OAEs)，代表了今天被开采的碳氢化合物的主要源岩。建议研究的中心是对中生代四个最突出的OAEs的调查(Toarcian Oae和白垩纪OAe1、2和3)。这些事件与显著的碳同位素漂移和生物灭绝和物种形成速率升高有关，表明对地球海洋、气候和生物系统的演化产生了广泛的影响。这些海洋环境事件将在从加拿大西部内陆航道(CWIS)到大西洋的中高纬度断面上进行研究。由于高纬度地区对控制全球海洋-大气环流系统非常重要，因此这些区域具有揭示大气层外环流形成的新线索的巨大潜力。将建立高分辨率的生物和化学地层学，以便在高纬度和低纬度剖面之间进行精确的地层对比，这对于了解OAE形成的过程、时间和空间扩展至关重要。此外，将采用已确立的新的环境变化指标(例如生产力)来重建导致海洋环境事件的古环境条件。为了开发新的环境指标，将分析全新世期间在地中海沉积的富含有机物质的沉积物--腐泥岩S1的形成。该腐蚀岩可作为缺氧沉积物形成的理想范例，并有可能开发新的古生物学指标来重建海洋生态系统。此外，将对选定的微化石群进行调查，以评估和量化与中高纬度样带OAEs形成有关的进化变化。这一断面将允许区分微化石随时间的进化趋势和生态趋势。

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.