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.

海平面上升预测中最大的不确定性在于，随着气候变暖，南极洲和格陵兰岛的大冰原将对海平面上升产生何种影响。西南极冰盖和南极半岛冰盖是最令人关切的问题，因为它们显示出大量冰损失的迹象，从理论上讲，它们是最脆弱的。有助于预测这些冰盖将如何随着气候变暖而变化的重要信息来源是南极洲周围海床沉积物中包含的它们对过去气候变化的反应记录。这样的记录比冰盖本身的冰芯还要久远。它们还可以显示冰盖的边缘如何与海洋温度和环流的变化相互作用，最近的研究已经确定海洋温度和环流对冰盖有重要影响。虽然南极洲附近浅海的沉积记录定期受到冰盖过去扩张的干扰或消除，在附近的深海中，有些地方的沉积物已经连续积累了数百万年。国际综合大洋钻探计划正在考虑一项建议，即派遣一艘钻探船从其中一些地方收集长沉积物岩心。然而，在此之前，还需要更多的调查数据，以找到能够提供最连续、最详细记录的地点，并确保在这些地点钻探是安全的。在这项研究提案中，我们正在寻求资金来收集这一重要的调查数据。在同一次考察中，我们还建议收集短的沉积物岩心进行试点研究，以确认我们打算对较长的钻孔岩心采用的分析方法将提供关于沉积物年龄、过去气候和过去冰盖行为的可靠信息。研究南极洲周围海床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，在世界上大多数海洋的岩芯中，用于确定沉积物年龄的微体化石类型在南极洲附近收集的许多沉积物岩芯中很少见或根本不存在。通过进行详细的调查和研究短岩心，我们希望确定有足够数量的微体化石的地点，以应用标准的测年技术。我们还计划测试一种基于磁性分析的沉积物测年新方法是否适用于拟议钻探地点的区域。最近的研究表明，在许多地方，对海底沉积物的磁性进行分析，可以提供过去地球磁场强度变化的记录，将这些记录与日期明确的参考记录进行比较，就可以确定整个岩芯中沉积物的年龄。通过比较使用这种方法获得的年龄与从微体化石中获得的年龄，我们将能够发现磁性测年方法在研究地区的工作情况。如果磁性方法效果良好，我们将能够在不依赖微体化石的情况下为岩心建立详细的年龄模型，这将大大扩展可以通过钻探研究的区域，并允许从岩心中获得更详细的过去变化记录。

项目成果

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

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

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

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