Sub-orbital climate instability and its relation to Late Pliocence intensification of Northern Hemisphere Glaciation, IODP Sites 1308 and 1313

亚轨道气候不稳定及其与上新世晚期北半球冰川作用强化的关系，IODP 站点 1308 和 1313

• 批准号: NE/F00141X/1
• 负责人: Paul Wilson
• 金额: $ 10.14万
• 依托单位: University of Southampton
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF00141X%2F1
• 关键词: Sub; orbital; climate; instability; its

One hundred million years ago (Ma), when dinosaurs walked Earth, most scientists think that the poles were free of the large icecaps that we see today. When and why did these icecaps form? How rapidly did they grow? Once established, how stable were they? These are some of the questions that we seek to answer by generating records of past climate change from sediment cores collected from the seafloor. One of our techniques is to count small rock fragments that have been scrapped off the continents by glaciers and delivered to the seafloor by calving and drifting of icebergs. Another is to measure the ratio of heavy and light oxygen isotopes (18O/16O) (known from laboratory experiments to be sensitive to ice-volume and temperature) trapped in the fossilised calcium carbonate shells of tiny single cellular marine animals called foraminifers. We already have a semi-continuous, semi-quantitative picture of climate change over the past 100 Ma. The pattern is one of gradual long-term cooling plus several big 'shifts' to more glaciated conditions. Superimposed on these changes are regular cycles in climate with distinct rhythms (eg. orbital cycles of ~100, 40 thousand years). Where we have high-enough resolution records (of the last 500 kyrs in particular) we see that superimposed on these rhythms are sub-orbital scale oscillations involving ice-sheet advance/collapse and ocean circulation change as popularised in the Hollywood blockbuster 'The Day After Tomorrow'. These oscillations are especially relevant to our concerns about the future. They demonstrate that, even without man's interference, the climate system in general and the North Atlantic region in particular is capable of undergoing massive re-organization extremely rapidly, within even a few decades (with extreme consequences for conditions in NW Europe in particular). Some suggest that sub-orbital scale oscillations are driven by forces external to Earth (eg. changes in solar insolation). Others think that internal forces are important because, we can see that in the last 500 kyrs sub-orbital oscillations were amplified when ice-sheets are large. Records of ice-rafted debris and oxygen isotopes from marine sediments suggest that large permanent continental ice-sheets were present in the northern hemisphere from ~2.72 Ma. One big question that arises, therefore, is: - how does sub-orbital scale climate variability evolve as the ice-sheets that are thought to amplify them form? In seeking to answer this question we have been hampered in the past by the lack of continuous, high-resolution records of change with excellent age control. However, careful application of modern drilling methods to sites of rapidly accumulating sediment is helping to remedy these problems. We propose to address the above problem by generating new palaeoclimate records of unprecedented continuity, resolution and age-control from the North Atlantic for the interval 2.84 Ma to 2.4 Ma. By determining the sensitivity of sub-orbital scale climate instability to glacial-interglacial state we can see how climate boundary conditions have changed since ~ 2.8 Ma.

一亿年前（MA），当恐龙走过地球时，大多数科学家认为杆子没有我们今天看到的大型冰op。这些ICECAPS何时以及为什么形成？他们成长的速度如何？建立后，它们的稳定性如何？这些是我们通过从海底收集的沉积物核心产生过去气候变化的记录来回答的一些问题。我们的技术之一是计算冰川从大洲取消的小岩石碎片，并通过冰山的产犊和漂流运到海底。另一个是测量被捕获在称为有孔虫的微型单细胞海洋动物的化石钙壳中的重氧同位素（18O/16O）（从实验室实验中知道对冰量和温度敏感）的比率。在过去的100 mA中，我们已经有了半连续的，半定量的情况。该模式是逐渐的长期冷却之一，再加上几个大的“转移”到更具冰川的条件。在这些变化上叠加的是气候下的常规循环，并具有不同的节奏（例如，轨道周期约为100，40千年）。在我们拥有高增强的分辨率记录的地方（尤其是最后500台kyr中），我们看到这些节奏叠加的是轨道尺度振荡，涉及冰淇淋前进/倒塌和海洋循环变化，因为好莱坞大片“当天”明天之后”。这些振荡与我们对未来的担忧特别相关。他们表明，即使没有人干扰，尤其是在几十年之内，尤其是北大西洋地区的气候系统，尤其是能够非常迅速地进行大规模重组（尤其是欧洲西北欧洲的条件极大的后果）。一些人认为亚轨道尺度振荡是由地球外部的力驱动的（例如，太阳失去的变化）。其他人则认为内部力很重要，因为我们可以看到，在冰盖很大时，在最后500台kyrs的亚轨道振荡被放大。海洋沉积物的冰上碎屑和氧同位素的记录表明，北半球有大量永久性大陆冰块，距离约2.72 mA。因此，出现的一个大问题是： - 随着被认为会放大它们形成的冰块，亚轨道规模的气候变化如何演变？在寻求回答这个问题的过程中，由于缺乏持续的高分辨率变化记录和出色的年龄控制，我们过去一直受到阻碍。但是，仔细地将现代钻井方法应用于迅速积聚的沉积物的站点有助于解决这些问题。我们建议通过产生从北大西洋的前所未有的连续性，解决方案和年龄控制的新古气候记录来解决上述问题。通过确定亚轨道尺度气候不稳定性对冰川间 - 冰川状态的敏感性，我们可以看到自2.8 mA以来气候边界条件如何变化。

项目成果

Testing planktic foraminiferal shell weight as a surface water [CO32-] proxy using plankton net samples

• DOI: 10.1130/g30150.1
• 发表时间: 2010-02-01
• 期刊: GEOLOGY
• 影响因子: 5.8
• 作者: Beer, Christopher J.;Schiebel, Ralf;Wilson, Paul A.
• 通讯作者: Wilson, Paul A.

North Atlantic Midlatitude Surface-Circulation Changes Through the Plio-Pleistocene Intensification of Northern Hemisphere Glaciation

• DOI: 10.1029/2018pa003412
• 发表时间: 2018-11-01
• 期刊: PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
• 影响因子: 3.5
• 作者: Bolton, Clara T.;Bailey, Ian;Wilson, Paul A.
• 通讯作者: Wilson, Paul A.

An alternative suggestion for the Pliocene onset of major northern hemisphere glaciation based on the geochemical provenance of North Atlantic Ocean ice-rafted debris

• DOI: 10.1016/j.quascirev.2013.06.004
• 发表时间: 2013-09-01
• 期刊: QUATERNARY SCIENCE REVIEWS
• 影响因子: 4
• 作者: Bailey, Ian;Hole, Georgia M.;Raymo, Maureen E.
• 通讯作者: Raymo, Maureen E.

Technical Note: On methodologies for determining the size-normalised weight of planktic foraminifera

• DOI: 10.5194/bg-7-2193-2010
• 发表时间: 2010-01-01
• 期刊: BIOGEOSCIENCES
• 影响因子: 4.9
• 作者: Beer, C. J.;Schiebel, R.;Wilson, P. A.
• 通讯作者: Wilson, P. A.

Flux and provenance of ice-rafted debris in the earliest Pleistocene sub-polar North Atlantic Ocean comparable to the last glacial maximum

• DOI: 10.1016/j.epsl.2012.05.034
• 发表时间: 2012-08-01
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Bailey, Ian;Foster, Gavin L.;Becker, Julia
• 通讯作者: Becker, Julia