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，该项目是使用来自西南极冰盖（WAIS）的现有样品将冰芯分开，以使用常见的时间顺序标记将其时间尺度与格陵兰冰芯的时间尺度保持一致。钻至3405 m深度的WAIS划分核的上部2850 m的日期高度很高。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突然气候事件的时机相对于格陵兰岛在上一个冰河时代的时机的理解。该项目的智力优点是进一步限制格陵兰和南极洲突然气候事件的相对时机，以获得对基本机制的关键见解。该项目的主要目的是将WAIS划分核心的当前时间尺度从31,000年前提高到65,000年前，它通过将此核心与Greenland Ice核心同步，使用Beryllium-10中的普通信号，这是BERYLLIUM-10，这是BE的放射性同位素，它是由宇宙射线在大气中产生的放射性同位素，并在其生产的1-2年内沉积在雪上。 10BE通量在很大程度上与气候信号无关，因为其产量随太阳能活动和地磁场而变化。该项目将进一步加强PI在伯克利的PI与美国和欧洲的ICE核心研究人员之间的合作，使本科生参与其研究的许多方面，并继续向不足的学生宣讲。 WAIS将冰芯与格陵兰冰核年表（GICC05）的直接冰球对冰同步预计有望减少格陵兰岛和南极洲突然气候事件的相对时间的不确定性减少几十年。为了实现这一目标，调查人员将在2850至3390 m深度的WAIS划分核心中获得10BE的连续高分辨率记录，并将获得的10BE记录与现有的10BE GREGYLAND ICE核心记录进行比较，包括GISP2和NGRIP。科学家将使用加速器质谱法（AMS）分开〜1000个WAIS划分核心的〜1000个冰样样品，并测量每个样品中的10BE浓度。 10BE测量值的更广泛的影响是，它们还将提供有关Laschamp事件的信息，这是大约41，000年前的2000年长期的低地磁田间强度，并改善了30,000年以上的有机样品的14C定型方法的校准。该项目的更广泛的影响包括（1）在冰核研究和加速器质谱测量中的参与和培训，（2）将冰核心和气候研究纳入普渡大学和伯克利大学和伯克利大学的持续外展计划中，（3）对过去的变化有所改善，（3）对未来的气候变化更好地理解，4（3）4（3）预测未来的变化，4（4）（4）（4）（4）在接下来的几百年中。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