EAGER: Constraining the Y-axis: Towards Quantitative Constraints for Precipitation and Temperature Using Speleothem Isotope and Trace Element Data

该项目在早期概念探索研究资助计划(EARGER)的支持下，重点研究如何利用质谱学和数据分析的最新进展，从古气候记录中产生温度和降水的定量测量。初步分析结果表明，碳酸盐中的88锶/86锶比值对温度变化敏感。有限的实验数据表明，生长动力学等其他因素可能对这一值起作用，这一理想关系被发现是复杂的。研究人员使用高温和低温碳酸盐进行了一些初步测量，数据令人鼓舞，88锶/86锶似乎与温度有很强的关系。然而，目前还没有令人信服的数据来证明与古气候相关的温度范围内的温度相关性。热电离质谱(TIMS)与“双尖峰”方法相结合的最新进展可以提供足够的准确度和精密度来检验这一想法。此外，斯坦顿堡洞穴中的石笋在从最后一次冰川到全新世早期的整个气候波动中生长，是分析的理想对象，而且正在研究中。锶同位素工作将在一个实验室进行尝试，该实验室配备了新一代放大器，使获得非常准确和精确的88锶/86锶比率成为可能，足以解决与古气候有关的尺度上潜在的温度变化。研究人员还将致力于设计一个可以容纳长石笋样本的样本室。该项目的另一个有希望的方面是，使用与电感耦合等离子体质谱(ICP-MS)仪器耦合的新型准分子激光在高通量和高质量元素数据方面取得的技术成就，以及使用机器学习查看数据的新方法。研究人员的初步结果表明，一些微量元素，特别是碱和碱土元素，可能会随着稳定同位素的变化而发生相干变化，从而为机器学习应用提供所需的多维数据。这些活动具有重要的科学意义，非常适合渴望项目的潜在变革性、高风险但潜在的高回报研究属性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project uses funds, under the auspices of the EArly Concept Grant For Exploratory Research (EAGER) program, to focus on ways to take advantage of recent advances in mass spectrometry and data analysis in order to produce quantitative measures of temperature and precipitation from the paleoclimate record.An initial analytical finding suggests that the 88Strontium/86Strontium ratio in carbonates is sensitive to changes in temperature. This ideal relationship has been found to be complicated by limited experimental data that suggest that other factors, such as growth kinetics may play a role in this value. The researcher made some initial measurements using high temperature and low temperature carbonates and the data are encouraging to the extent that there seems to be a strong relationship between 88Strontium/86Strontium and temperature. There is no data on hand, however, to convincingly demonstrate temperature dependence in the range of temperature relevant for paleoclimate. Recent advances in thermal ionization mass spectrometry (TIMS) coupled with the "double spike" method could allow enough accuracy and precision to test the idea. In addition, stalagmites from Fort Stanton Cave that grew through the full climate swings that took place from the Last Glacial to the Early Holocene are ideal for analysis and are in-hand. The Strontium isotopic work will be attempted in a laboratory that houses a new generation of amplifier that would make it possible to obtain very accurate and precise 88Strontium/86Strontium ratios, sufficient to resolve potential changes in temperature at a scale relevant for paleoclimate. The researcher will also work on the design of a sample chamber that can accommodate long stalagmite samples.Another aspect of the project that holds promise is the combined technical achievements in high-throughput and high-quality elemental data using newer excimer lasers coupled to inductively coupled plasma mass spectrometry (ICP-MS) instruments and new ways to look at data using machine learning. Initial results by the researcher show that some trace elements, especially alkali and alkali-earth elements, may coherently vary with stable isotopes, thus providing the multidimensional data needed for machine learning applications. The activities are scientifically important and fit well into the potentially transformative, high-risk but potential high payoff research attributes of the EAGER program.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.