Collaborative Research: Synchronizing the WAIS Divide and Greenland Ice Cores from 30-65 ka BP Using High-resolution 10Be Measurements

合作研究：使用高分辨率 10Be 测量同步 WAIS 分水岭和格陵兰冰芯 30-65 ka BP

• 批准号: 1644128
• 负责人: Kees Welten
• 金额: $ 32.09万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-02-01 至 2022-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1644128&HistoricalAwards=false
• 关键词: Collaborative; Research; Synchronizing; WAIS; Divide

Welten/1644128 This award supports a project to use existing samples from the West Antarctic Ice Sheet (WAIS) Divide ice core to align its timescale with that of the Greenland ice cores using common chronological markers. The upper 2850 m of the WAIS Divide core, which was drilled to a depth of 3405 m, has been dated with high precision. The timescale of the remaining (bottom) 550 m of the core has larger uncertainties, limiting our understanding of the timing of abrupt climate events in Antarctica relative to those in Greenland during the last ice age. The intellectual merit of this project is to further constrain the relative timing of these abrupt climate events in Greenland and Antarctica to obtain crucial insight into the underlying mechanism. The main objective of this project is to improve the current timescale of the WAIS Divide core from 31,000 to 65,000 years ago by synchronizing this core with the Greenland ice cores using common signals in Beryllium-10, a radioactive isotope of Be that is produced in the atmosphere by cosmic rays and is deposited onto the snow within 1-2 years of its production. The 10Be flux is largely independent of climate signals since its production varies with solar activity and the geomagnetic field. This project will further strengthen collaborations between the PI's in Berkeley and Purdue with ice core researchers in the US and Europe, involve undergraduate students in many aspects of its research, and continue outreach to under-represented students. The direct ice-to-ice synchronization of the WAIS Divide ice core with the Greenland Ice Core Chronology (GICC05) using cosmogenic 10Be is expected to reduce the uncertainty in the relative timing of more than 20 abrupt climate events in Greenland and Antarctica to a few decades. To achieve this goal the investigators will obtain a continuous high-resolution record of 10Be in the WAIS Divide core from 2850 to 3390 m depth, and compare the obtained 10Be record with existing 10Be records of the Greenland ice cores, including GISP2 and NGRIP. The scientists will separate 10Be from ~1000 ice samples of the WAIS Divide core and measure the 10Be concentration in each sample using accelerator mass spectrometry (AMS). Broader impacts of the 10Be measurements are that they will also provide information on the Laschamp event, a ~2000 year long period of low geomagnetic field strength around 41,000 years ago, and improve the calibration of the 14C dating method for organic samples older than 30,000 years. The broader impacts of the project include (1) the involvement and training of undergraduate students in ice core research and accelerator mass spectrometry measurements, (2) the incorporation of ice core and climate research into ongoing outreach programs at Purdue University and Berkeley SSL, (3) better understanding of abrupt climate changes in the past will improve our ability to predict future climate change, (4) evaluating the possible threat of a future geomagnetic excursion in the next few hundred years. This award does not require support in Antarctica.

Welten/1644128 该奖项支持一个项目，该项目使用来自西南极冰盖 (WAIS) Divide 冰芯的现有样本，使用常见的年代标记将其时间尺度与格陵兰冰芯的时间尺度保持一致。 WAIS Divide 岩心上部 2850 m 的钻探深度为 3405 m，已进行了高精度测年。核心剩余（底部）550 m 的时间尺度具有更大的不确定性，限制了我们对南极洲相对于格陵兰岛在上一个冰河时期发生的突变气候事件的时间的理解。该项目的智力价值在于进一步限制格陵兰岛和南极洲这些突发气候事件的相对时间，以获得对潜在机制的重要见解。该项目的主要目标是通过使用铍 10（一种铍的放射性同位素，在大气中的宇宙射线，并在其产生后 1-2 年内沉积到雪上。 10Be 通量在很大程度上与气候信号无关，因为它的产生随太阳活动和地磁场而变化。该项目将进一步加强伯克利和普渡大学的 PI 与美国和欧洲的冰芯研究人员之间的合作，让本科生参与其研究的许多方面，并继续向代表性不足的学生进行推广。使用宇宙成因 10Be 的 WAIS Divide 冰芯与格陵兰冰芯年代学 (GICC05) 的直接冰对冰同步预计将把格陵兰岛和南极洲 20 多个突发气候事件的相对时间的不确定性减少到几个几十年。为了实现这一目标，研究人员将获得 WAIS Divide 冰芯 2850 至 3390 米深度的连续高分辨率 10Be 记录，并将获得的 10Be 记录与格陵兰冰芯现有的 10Be 记录（包括 GISP2 和 NGRIP）进行比较。科学家们将从 WAIS Divide 核心的约 1000 个冰样本中分离出 10Be，并使用加速器质谱 (AMS) 测量每个样本中的 10Be 浓度。 10Be 测量的更广泛影响在于，它们还将提供有关 Laschamp 事件（大约 41,000 年前约 2000 年的低地磁场强度时期）的信息，并改进对 30,000 年前有机样品的 14C 测年方法的校准。该项目更广泛的影响包括（1）本科生参与和培训冰芯研究和加速器质谱测量，（2）将冰芯和气候研究纳入普渡大学和伯克利 SSL 正在进行的外展项目，（ 3）更好地了解过去的气候突变将提高我们预测未来气候变化的能力，（4）评估未来几百年未来地磁偏移的可能威胁。该奖项不需要南极洲的支持。

项目成果

Deep-water circulation changes lead North Atlantic climate during deglaciation

• DOI: 10.1038/s41467-019-09237-3
• 发表时间: 2019-03
• 期刊: Nature Communications
• 影响因子: 16.6
• 作者: F. Muschitiello;W. D'Andrea;A. Schmittner;T. Heaton;N. Balascio;Nicole deRoberts;M. Caffee;T. Woodruff