A reference time scale for the study of Pleistocene orbital and millennial-scale climate variability: IODP Site U1385 ("Shackleton site")

研究更新世轨道和千年尺度气候变化的参考时间尺度：IODP Site U1385​​（“Shackleton site”）

• 批准号: NE/K005804/1
• 负责人: David Hodell
• 金额: $ 29.2万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FK005804%2F1
• 关键词: reference; time; scale; study; Pleistocene

Future advances in our understanding of the Earth's climate system will rely on our ability to link high-resolution sedimentary archives from the oceans, ice-cores and terrestrial sequences, and to interpret these records in the context of novel Earth system modeling approaches. Few places exist in the world where sufficiently detailed and unambiguous marine-ice-terrestrial linkages are possible. The western Iberian Margin represents such a location, and provides a rare opportunity for recovering key sequences needed to for marine-ice-terrestrial correlation. During Expedition 339, we drilled five holes at Site U1385 ("Shackleton site") to a maximum depth of 166.5 mcd, and recovered a continuous record of hemipelagic sedimentation from the Holocene to 1.42 Ma (Marine Isotope Stage 46) with average sedimentation rates of ~10 cm kyr-1. The high-resolution core logging, colour, and XRF data already obtained demonstrate the great potential of this site for studying the history of Pleistocene climate change on orbital and suborbital time scales. Before these records can be fully exploited, however, a well-founded chronology must be developed for Site U1385. Here we propose to develop such a detailed reference time scale to which all future studies of Site U1385 will refer. A robust time scale is particularly important as the Shackleton site is likely to become a "marine reference section" for global correlation and against which other climate records will inevitably be compared.. Once the age model has been established, it can be transferred to the various time series we have already collected (e.g., magnetic susceptibility, density, NGR, scanning XRF, and colour) and those that will be produced by this project (planktonic and benthonic d18O and d13C, benthic Mg/Ca) and our project partners (alkenone and foraminiferal sea surface temperature estimates). Time series analysis will be used to address several fundamental questions regarding the coevolution of Pleistocene orbital and suborbital climate variability under changing orbital and glacial boundary conditions:Orbital: What are the phasings of proxy climate variables at Milankovitch frequencies and what do they tell us about the response of different components of the climate system to insolation forcing? How do the observed phasings compare with the system model proposed by Imbrie et al. (1992) detailing the geographic progression of local responses to insolation forcing? Has the phasing changed through the Pleistocene when the average climate state evolved toward generally colder conditions with larger ice sheets, and the spectral character of climate variability shifted from dominantly 41 to 100 kyrs?Suborbital: How does the frequency and pacing of millennial-scale variability vary among glacial periods of the last 1.4 Ma? Is the amplitude and/or frequency of millennial variations related to an ice volume threshold? Does Earth's orbital geometry influence the nature (magnitude and/or frequency) of suborbital climate variability (e.g., through frequency modulation)? How did millennial-scale climate variability change across the Middle Pleistocene transition? Do millennial-scale climatic oscillations play a role in initiating glacial terminations or are they principally orbitally driven?The results of this project will benefit the many scientists of IODP Expedition 339 working on Site U1385 by establishing a chronostratigraphic foundation for this important marine reference section.

我们对地球气候系统的理解的未来进步将取决于我们将高分辨率沉积档案与海洋，冰核和地面序列联系起来的能力，并在新型的地球系统建模方法的背景下解释了这些记录。世界上很少有地方可以使用足够详细且明确的海洋冰冰球联系。伊比利亚西部的边缘代表了这样一个位置，并为恢复海洋冰 - 透道相关所需的关键序列提供了难得的机会。在Expedition 339期间，我们在现场U1385​​（“ Shackleton站点”）钻了五个孔，最大深度为166.5 MCD，并收回了从全新世到1.42 mA（Marine Isotope Stage 46）的连续记录，平均沉淀率为〜10 cm Kyr-1。已经获得的高分辨率核心记录，颜色和XRF数据证明了该站点在轨道和亚轨道时间尺度上研究更新世气候变化的历史的巨大潜力。但是，在完全利用这些记录之前，必须为U1385​​开发有充分的年代。在这里，我们建议开发这样的详细参考时间量表，所有网站U1385​​的未来研究都将参考。稳健的时间尺度特别重要，因为沙克尔顿站点可能会成为全球相关性的“海洋参考部分”，并且与其他气候记录将不可避免地比较。 D18O和D13C，底栖MG/CA）以及我们的项目合作伙伴（烯酮和有孔虫海面温度估计）。时间序列分析将用于解决有关在不断变化的轨道和冰川边界条件下更新世轨道和亚轨道气候变异性共同进化的几个基本问​​题：轨道：摩西维提奇频率的代理气候变量的相位是什么？观察到的相位与Imbrie等人提出的系统模型相比。 （1992）详细介绍了局部对无生动强迫的反应的地理发展？当平均气候状态朝着较大的冰盖越来越寒冷的条件演变而来，而气候变异性的光谱从41 kyrs转移到较大的条件？亚轨道上的频谱特征是如何变化的？千年尺度变化的频率和起搏如何在最后1.4 mA的糖化时期变化如何？千禧一代变化的幅度和/或频率是否与冰量阈值相关？地球的轨道几何形状会影响亚轨道气候变异性（例如，通过频率调制）的性质（幅度和/或频率）吗？千禧一代气候变化如何变化整个更新世过渡？千禧一代的气候振荡在启动冰川终止方面发挥了作用，还是主要是轨道驱动的？该项目的结果将使IODP Expedition 339的许多科学家339在现场U1385​​上工作，通过建立该重要的海洋参考参考部分的计时术语，从而在现场U1385​​上工作。

项目成果

Revisiting the relationship between the pore water carbon isotope gradient and bottom water oxygen concentrations

重新审视孔隙水碳同位素梯度与底层水氧浓度之间的关系

• DOI: 10.5194/egusphere-egu22-7896
• 发表时间: 2022
• 作者: Bradbury H

Quantitative estimation of bioturbation based on digital image analysis

• DOI: 10.1016/j.margeo.2014.01.003
• 发表时间: 2014-03-01
• 期刊: MARINE GEOLOGY
• 影响因子: 2.9
• 作者: Dorador, Javier;Rodriguez-Tovar, Francisco J.
• 通讯作者: Rodriguez-Tovar, Francisco J.

Oceanic heat pulses fueling moisture transport towards continental Europe across the mid-Pleistocene transition

• DOI: 10.1016/j.quascirev.2017.11.009
• 发表时间: 2018-01-01
• 期刊: QUATERNARY SCIENCE REVIEWS
• 影响因子: 4
• 作者: Bahr, A.;Kaboth, S.;Friedrich, O.
• 通讯作者: Friedrich, O.

A reference time scale for Site U1385 (Shackleton Site) on the SW Iberian Margin

西伊比利亚边缘 U1385​​ 站点（沙克尔顿站点）的参考时间尺度

• DOI: 10.1016/j.gloplacha.2015.07.002
• 发表时间: 2015-10-01
• 期刊: GLOBAL AND PLANETARY CHANGE
• 影响因子: 3.9
• 作者: Hodell, D.;Lourens, L.;Tzedakis, P. C.
• 通讯作者: Tzedakis, P. C.

Virtual special issue on IODP Expedition 339: The Mediterranean outflow

• DOI: 10.1016/j.gloplacha.2016.06.016
• 发表时间: 2016-07
• 期刊: Global and Planetary Change
• 影响因子: 3.9
• 作者: D. Hodell;F. Hernández‐Molina;D. Stow;C. Alvarez‐Zarikian