Completing the Eocene cyclostratigraphy - new perspectives from a greenhouse world

我们项目的目的是在确定整个始新世(55至34 Ma)大西洋和太平洋以前所未有的分辨率稳定的长偏心旋回的基础上，首次建立一个完整的旋回地层学框架。这两个大洋的预期年龄模型的准确性将使人们能够非常详细地了解始新世温室气候的总体变化，以及向更凉爽的古近纪晚期气候状态的过渡。在这里提出的第三年，我们计划根据目前正在发展的非常令人兴奋的结果来完善和扩大我们的记录。这些额外的分析对于实现我们项目的科学目标至关重要。新的磁性地层学数据涵盖了208个地段的磁极Chron C23和C24n，以及用于确定磁极Chron C18n确切持续时间的额外稳定同位素数据，这些都是完成始新世大西洋地层格架的关键记录。在我们正在进行的项目第一阶段非常有希望的结果的基础上，我们设想为另外两个相对较短的高分辨率海底同位素记录调查更多选定的间隔。这对于检验地球S的气候是否在始新世-渐新世转换前1200多万年前始新世气候最佳时期的极端温暖世界结束后的长期冷却结束时是通过一系列单独的步骤而不是逐渐冷却是很重要的。最终，综合和综合该项目的所有磁学、化学和旋回地层学数据，将大大有助于记录始新世中晚期高温事件的发生和频率，了解它们与轨道强迫的关系，以及它们与温室气候动力学的关系。

The aim of our project is to establish a for the first time complete cyclostratigraphic framework based on the identification of the stable long eccentricity cycle for the entire Eocene (55 to 34 Ma) for both the Atlantic and Pacific oceans at unprecedented resolution. The accuracy of the intended age model for both oceans will allow very detailed insights into the Eocene greenhouse climate variability in general and the transition to a cooler Late Paleogene climate state. In the here proposed third year we plan to round-off and extend our records based on the right now evolving, very exciting results. These additional analyses are crucial to achieve the scientific objectives of our project. New magnetostratigraphic data covering magnetic polarity Chrons C23 and C24n at Leg 208 sites and additional stable isotope data to determine the exact duration of magnetic polarity Chron C18n are key records for completing the Eocene Atlantic stratigraphic framework. Built on the very promising results from the ongoing first phase of our project we envisage investigating additional selected intervals for two additional, relative short high-resolution benthic isotope records. This is important to test whether Earth´s climate cooled through a series of individual steps rather than gradually at the end of the long-term cooling following the extremely warm world of the Early Eocene Climate Optimum more than 12 million years before the Eocene - Oligocene transition. Ultimately, integrating and synthesizing all magneto-, chemo-, and cyclostratigraphic data of the project will substantially contribute to document the occurrence and frequency of middle to late Eocene hyperthermal events, understanding their relationship to orbital forcing, and their relationship to greenhouse climate dynamics.