Depositional patterns and records in sediment drifts off the Antarctic Peninsula and West Antarctica

南极半岛和南极洲西部沉积物的沉积模式和记录

• 批准号: NE/J006513/1
• 负责人: David Hodell
• 金额: $ 4.84万
• 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%2FJ006513%2F1
• 关键词: Depositional; patterns; records; sediment; drifts

The biggest uncertainty in predictions of sea-level rise is what the contribution will be from the great ice sheets on Antarctica and Greenland as climate warms. The West Antarctic Ice Sheet and the Antarctic Peninsula Ice Sheet are the cause of greatest concern, as they are showing signs of significant ice loss and there are theoretical reasons for expecting them to be most vulnerable. Important sources of information for helping to predict how these ice sheets will change as climate warms are records of their response to past climate changes contained in sea bed sediments around Antarctica. Such records extend further back in time than ice cores from the ice sheets themselves. They can also show how the margins of the ice sheets interacted with changes in ocean temperature and circulation, which recent studies have identified as having an important influence on ice sheets.Although sedimentary records in the shallow seas close to Antarctica have been periodically disturbed or removed by past expansions of the ice sheets, there are places in the nearby deep ocean where sediments have accumulated continuously over millions of years. The international Integrated Ocean Drilling Program is considering a proposal to send a drilling ship to collect long sediment cores from some of these places. However, before this is done additional survey data are needed to find the sites that will provide the most continuous, detailed records and to make sure that it will be safe to drill those sites. In this research proposal we are seeking funding to collect this essential survey data. On the same expedition we also propose to collect short sediment cores for pilot studies to confirm that the analytical methods we intend to apply to the longer drill cores will provide reliable information about sediment ages, past climate and past ice sheet behaviour. One of the major difficulties in studying sediment records from the sea bed around Antarctica has been obtaining reliable ages from the sediments. This is because the types of microfossils that are analysed to determine sediment ages in drill cores from most of the world's oceans are rare or absent in many sediment cores collected near Antarctica. By carrying out detailed survey and studying short cores we hope to identify sites where there are sufficient numbers of these microfossils to apply the standard dating techniques. We also plan to test whether a new method of dating sediments that is based on analysis of their magnetic properties will work in the area of the proposed drill sites. It has recently been shown that in many places analysis of the magnetic properties of sea bed sediments can provide records of past changes in the intensity of the Earth's magnetic field, and comparison of these records to well-dated reference records allows ages to be assigned to sediments throughout a core. By comparing ages obtained using this method with ones obtained from microfossils, where they are present, we will be able to find out how well the magnetic dating method works in the study area. If the magnetic method works well, we will be able to establish detailed age models for drill cores without dependence on microfossils, which will greatly extend the area that can be studied by drilling and allow more detailed records of past changes to be derived from the drill cores.

海平面上升预测的最大不确定性是，随着气候温暖，南极和格陵兰的大冰块的贡献将是什么。南极冰盖和南极半岛冰盖是最引起人们最大关注的原因，因为它们表现出巨大的冰损失的迹象，并且有理论上的理由期望它们最脆弱。随着气候温暖的记录，它们对南极洲周围海床沉积物中过去的气候变化的反应记录，有助于预测这些冰盖将如何变化的重要信息来源。这些记录比冰盖本身的冰芯更及时地延伸。他们还可以展示冰盖的边缘如何与海洋温度和循环的变化相互作用，最近的研究确定为对冰块产生重要影响。尽管在接近南极洲的浅海中，沉积记录已被定期扰乱或消除，或者由于过去在附近的深海中存在冰上的地方，在冰上占据了附近的矿物的膨胀，这些矿石在矿床中占据了千利月的占多年的磨难。国际综合海洋钻探计划正在考虑一项提议，要求从其中一些地方派出一艘钻探船以收集长长的沉积物核心。但是，在完成此操作之前，需要进行其他调查数据，以找到将提供最连续，详细记录的站点，并确保钻探这些站点是安全的。在这项研究建议中，我们正在寻求资金来收集此基本的调查数据。在同一探险中，我们还建议收集简短的沉积物核心进行试点研究，以确认我们打算应用于更长的钻芯的分析方法将提供有关沉积物年龄，过去气候和过去冰盖行为的可靠信息。从南极洲周围的海床研究沉积物记录的主要困难之一是从沉积物中获得可靠的年龄。这是因为在南极洲附近收集的许多沉积物核心中，经过分析以确定来自世界大多数海洋的钻头岩心的沉积物年龄的微化石类型。通过进行详细的调查并研究短核心，我们希望确定有足够数量的这些微化石来应用标准约会技术的地点。我们还计划测试一种基于对其磁性特性的分析的新约会沉积物的新方法是否会在拟议的钻探位置的区域中起作用。最近已经显示，在许多地方分析了海床沉积物的磁性特性可以提供地球磁场强度的过去变化的记录，并且将这些记录与良好的参考记录进行比较允许将年龄分配给整个核心的沉积物。通过比较使用此方法获得的年龄与从微化石获得的年龄进行比较，我们将能够找出磁性约会方法在研究区域的效果。如果磁方法效果很好，我们将能够建立钻孔核心的详细年龄模型，而不依赖微化石，这将大大扩展可以通过钻探研究的区域，并允许更详细的过去变化记录，这些变化是从钻芯中得出的。

项目成果

New insights from multi-proxy data from the West Antarctic continental rise: Implications for dating and interpreting Late Quaternary palaeoenvironmental records

来自西南极洲大陆隆起的多代理数据的新见解：对晚第四纪古环境记录的年代测定和解释的启示

• DOI: 10.1016/j.quascirev.2021.106842
• 发表时间: 2021
• 期刊: Quaternary Science Reviews
• 影响因子: 4
• 作者: Hillenbrand C

Relative paleointensity (RPI) and age control in Quaternary sediment drifts off the Antarctic Peninsula

• DOI: 10.1016/j.quascirev.2019.03.006
• 发表时间: 2019-05
• 期刊: Quaternary Science Reviews
• 影响因子: 4
• 作者: J. Channell;C. Xuan;D. Hodell;S. Crowhurst;R. Larter

Boundary processes and neodymium cycling along the Pacific margin of West Antarctica

南极洲西部太平洋边缘的边界过程和钕循环

• DOI: 10.1016/j.gca.2022.04.012
• 发表时间: 2022
• 期刊: Geochimica et Cosmochimica Acta
• 影响因子: 5
• 作者: Wang R

West Antarctic Ice Sheet retreat driven by Holocene warm water incursions.

• DOI: 10.1038/nature22995
• 发表时间: 2017-07-05
• 期刊: Nature
• 影响因子: 64.8
• 作者: Hillenbrand CD;Smith JA;Hodell DA;Greaves M;Poole CR;Kender S;Williams M;Andersen TJ;Jernas PE;Elderfield H;Klages JP;Roberts SJ;Gohl K;Larter RD;Kuhn G
• 通讯作者: Kuhn G