OPP-PRF: Investigating 2.5k Years of Human History and Atmospheric Transport in Greenland Ice Using High-Resolution Lead Isotopic Records

极地冰盖和冰川记录了近几十年、几百年和几千年来气候和环境的变化。从极地冰盖和冰川提取的岩心中发现的铅污染反映了人类活动，包括与早期白银生产有关的采矿和冶炼，以及煤炭、石油和汽油燃烧。冰川冰中铅的同位素分析可以用来确定过去排放源的变化。将在五个格陵兰冰芯中测量铅同位素，以确定和量化过去2500年来北半球人为排放源的变化，并评估这些变化与从古至今的历史事件之间的联系。这些记录有可能改变人们对瘟疫、社会动荡、战争以及采矿和冶炼技术进步等事件如何影响人类历史的理解。该研究员将于2022年秋季担任跨学科研究生和早期职业研究员冰芯科学与自然档案协调研讨会的讲师，分享技术和初步结果，并将参加其他旨在提高STEM领域可及性和包容性的外展活动。铅（Pb）同位素将在四个先前分析过的冰芯（NGRIP2， NASAU， RECAP和NUUS_2015）中收集的现有离散融水样本中进行测量，第五个冰芯（Tunu_2022）将在2022年收集和分析，作为正在进行的NSF项目（1925417）的一部分。最近开发的方法可以在浓度低至0.05 ng g-1的情况下对206Pb、207Pb和208Pb进行低不确定度的同位素测量，使冰芯的高分辨率分析成为可能。作为拟议研究的一部分，这些新方法的改进可以通过降低低丰度204Pb所需浓度（低至0.02 ng g-1）和测量不确定度进一步提高分辨率和解释能力。如果成功，这样的204Pb测量将是第一批用于解释极地冰记录的测量之一。提出的测量方法将提高20世纪前冰中铅同位素记录的分辨率，特别是那些来自古代和中世纪时期的记录，因为只有少数几个值被公布。评估将利用沙漠研究所与古代历史学家、考古学家和大气科学家之间的合作。本研究结果将用于评价冰芯解释中广泛使用的大气输送和沉积模式的准确性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Polar ice sheets and glaciers record changes in climate and the environment during recent decades, centuries, and millennia. Lead pollution found in cores extracted from polar ice sheets and glaciers reflects human activities, including mining and smelting related to early silver production, as well as coal, oil, and gasoline burning. Isotopic analyses of lead in glacier ice can be used to identify past changes in emission sources. Lead isotopes will be measured in five Greenland ice cores to identify and quantify changes in Northern Hemisphere anthropogenic emission sources during the past 2500 years and to evaluate linkages between these changes and historical events extending from antiquity to the present. These records have the potential to transform understanding of how events such as plague, social upheaval, warfare, and technological advancements in mining and smelting influenced human history. The investigator will serve as an instructor for the Interdisciplinary Graduate and Early Career Researcher Consilience Workshop on Ice Core Science and Natural Archives in Fall 2022 sharing techniques and preliminary results and will participate in other outreach activities focused on improving accessibility and inclusivity in STEM fields. Lead (Pb) isotopes will be measured in existing discrete meltwater samples collected from four previously analyzed ice cores (NGRIP2, NASAU, RECAP, and NUUS_2015), as well as a fifth core (Tunu_2022) to be collected and analyzed in 2022 as part of an ongoing NSF project (1925417). Recently developed methods allow isotopic measurements of 206Pb, 207Pb, and 208Pb with low uncertainties at concentrations as low as 0.05 ng g-1, making high-resolution analyses in ice cores feasible. Refinement of these new methods as part of the proposed research may further increase resolution and improve interpretive power by reducing required concentrations (down to 0.02 ng g-1) and measurement uncertainties of low abundance 204Pb. If successful, such 204Pb measurements would be among the first used to interpret polar ice records. The proposed measurements will improve resolution of pre-20th-century Pb isotopic records from ice, particularly those from antiquity and the medieval period, for which only a handful of values have been published. Evaluation will leverage collaborations between Desert Research Institute and ancient historians, archaeologists, and atmospheric scientists. The detailed Pb source apportionment resulting from this research will be used to evaluate the accuracy of atmospheric transport and deposition models widely used for ice core interpretation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.