Closing the mid-Eocene palaeoceanography and time scale gap and testing Eocene climate hypotheses with material and data from IODP Expedition 342 (Newfoundland)

作为国际“始新世稳定同位素联盟”的一部分，该提案利用了纽芬兰东南海岭（IODP Exp. 342 Shipboard Scientists，2012）开发一个精确的、天文学校准的始新世年龄模型，然后可以应用于新生成的耦合底栖和浮游稳定同位素重建，通过详细描述整个时期的古海洋学变化，解决有关北大西洋海洋环流、气候和碳循环行为的重要问题。通过这样做，这一建议旨在重新审视一套相互关联的问题，有关的演变始新世地球系统。建立第一个基于单一地点的始新世完整的旋回地层年龄模型。关闭“始新世空白”和领带数据到一个绝对的天体年代学模型;评估是否有主导强迫响应频率和古气候条件（冰盖的存在）2之间的关系。生成始新世（34-56 Ma）的高分辨率、天文调谐的底栖和南极有孔虫（表面和温跃层）d13 C和d18 O时间序列，重点是生成磁时C20 r（~约）内的高分辨率混合层和温跃层南极稳定同位素序列。44.3-46.2 Ma）研究早始新世到晚始新世轨道节奏气候和碳循环动力学的大小（和敏感性）。与主要始新世碳循环事件的全球性质有关的测试假设（Pälike等人，2012年），包括赤道太平洋始新世长期加深的方解石补偿深度（CCD）和碳酸盐积累事件（CAE）。342号考察队的沉积序列对实现这些目标特别有用，因为整个始新世的连续沉积，在始新世中期至晚期的沉积速率特别高，是极好的微体化石保存的窗口，一组极好的生物和古地磁数据，以及测试始新世深水形成假说的关键位置。

This proposal, as part of an international "Eocene stable isotope consortium", exploits the opportunity provided by newly drilled sediment drift deposits on the Southeast Newfoundland Ridge (IODP Exp. 342 Shipboard Scientists, 2012) to develop a refined, astronomically calibrated age model for the Eocene, that can then be applied to a newly generated coupled benthic and planktonic stable isotope reconstruction to address important questions about the North Atlantic ocean circulation, climate, and carbon cycle behaviour by detailing palaeoceanographic changes throughout the epoch. By doing so, this proposal seeks to revisit a suite of interrelated questions regarding the evolution the Eocene Earth System.Major objectives of this proposal are:1. Develop the first complete cyclostratigraphic age model for the Eocene based on a single locale. Close the "Eocene gap" and tie data into an absolute astrochronological age model; evaluate whether there is a relationship between dominant forcing response frequency and palaeoclimatic condition (presence of ice-sheets)2. Generate a high-resolution, astronomically tuned benthic and planktic foraminiferal (surface and thermocline) d13C and d18O time series for the Eocene (34-56 Ma), with a focus for this proposal to generate high resolution mixed layer and thermocline planktic stable isotope series within magnetochron C20r (~ca. 44.3-46.2 Ma Ma)3. Examine the magnitude (and sensitivity) of orbitally paced climate and carbon cycle dynamics across the Early to Late Eocene.4. Test hypotheses relating to the global nature of major Eocene carbon cycle events (Pälike et al., 2012), including the Equatorial Pacific Eocene-long deepening of the calcite compensation depth (CCD) and carbonate accumulation events (CAEs).The sedimentary successions from Expedition 342 are particularly useful to achieve these objectives because of continuous sedimentation throughout Eocene, with particularly high sedimentation rates in the middle to lower late Eocene, windows of excellent microfossil preservation, an excellent set of bio- and palaeomagnetic datums, and a key location to test hypotheses about Eocene deep water formation.