Collaborative Research: Improving and calibrating a Tunable Infrared Laser Direct Absorption Spectroscopy (TILDAS) system for clumped isotope analysis of CO2

合作研究：改进和校准用于 CO2 聚集同位素分析的可调谐红外激光直接吸收光谱 (TILDAS) 系统

• 批准号: 1933130
• 负责人: Katharine Huntington
• 金额: $ 5.02万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-15 至 2022-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1933130&HistoricalAwards=false
• 关键词: Collaborative; Research; Improving; calibrating; Tunable

The study of “clumped-isotopes” concerns the tendency of heavy isotopes to “clump” into bonds with each other rather than with light isotopes in natural materials, a tendency that is temperature dependent. The co-occurrence of two rare and more massive isotopes of carbon and oxygen clumped in CO2 holds information on the temperature of the most recent chemical reactions involving these molecules. Clumped-isotope geochemistry has been applied to a wide range of subjects – from constraining atmospheric CO2 budgets to the temperature histories of meteorites. Measurements of clumping in CO2 have enabled new advances in reconstructing hydrothermal systems, climate history, paleoelevation, and the cooling history of the upper crust. The primary reason that this methodology is not more widely practiced is the difficulty of the measurement. This award will deliver a new laser-based instrument for measurement of clumped isotopes in carbonates that is much faster, cheaper, and requires less sample material than existing mass spectrometer systems. This new instrument will completely alter the landscape for clumped isotope research, making it a commonplace analysis. Such a system would be adopted quickly by laboratories around the world for application to geologic, oceanographic, biologic, and atmospheric samples, leading to new research possibilities in many scientific disciplines. This project also expands training and educational opportunities in this unusual sub-discipline of geochemistry. This project will support a postdoctoral researcher, strengthen international collaborations, and disseminate results through a conference session on laser methods. The project will also integrate research and education, broaden the participation of underrepresented groups, and broadly disseminate results by supporting a STEM Futures Fellowship research experience for undergraduates who identify with historically underrepresented groups in geoscience. This project builds on our previous funded work to develop a working laser-based (Tunable Infrared Laser Direct Absorption Spectroscopy - TILDAS) instrument for the rapid and precise measurement of clumped isotopologues of CO2 (e.g., 13C18O16O). The basic instrument has been constructed, but additional improvements in stability and development of practical sample processing are needed to produce an instrument that can be used widely in the scientific community. This laser-based measurement has major advantages over the currently used mass spectrometry approach in that it is much faster, taking only 20 minutes of analysis to achieve the required precision. Small sample size (comparable to the smallest mass spectrometer systems, and with the potential for further reductions) and a major increase in through-put will allow geochemists to extract previously unobtainable detailed temperature information from finely layered archives such as shell, fish otoliths, speleothems, soil carbonates, tufas and travertines. Fine sampling will also allow researchers to more effectively dissect diagenetic histories in carbonates, address questions related to solid-state reordering, study zoned fracture-filling cements precipitated in the sub-surface, and study kinetic and vital effects.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.

“团块同位素”的研究关注的是天然物质中重同位素相互“团块”成键的趋势，而不是与轻同位素成键的趋势，这种趋势与温度有关。聚集在二氧化碳中的两种罕见且质量更大的碳和氧同位素的共存，提供了涉及这些分子的最新化学反应温度的信息。块状同位素地球化学已被广泛应用于从限制大气二氧化碳收支到陨石的温度历史等领域。对CO2结块的测量在重建热液系统、气候历史、古海拔和上地壳冷却历史方面取得了新的进展。这种方法没有得到广泛应用的主要原因是测量的困难。该合同将提供一种新的基于激光的仪器，用于测量碳酸盐中的团块同位素，该仪器比现有的质谱仪系统更快，更便宜，并且需要更少的样品材料。这种新仪器将彻底改变团块同位素研究的格局，使其成为一种常见的分析方法。这样的系统将很快被世界各地的实验室采用，用于地质、海洋学、生物学和大气样品，从而在许多科学学科中产生新的研究可能性。该项目还扩大了地球化学这一不同寻常的分支学科的培训和教育机会。该项目将支持一名博士后研究人员，加强国际合作，并通过激光方法会议传播研究成果。该项目还将整合研究和教育，扩大代表性不足群体的参与，并通过支持STEM未来奖学金（STEM Futures Fellowship）的研究经验，广泛传播成果，为那些认同历史上代表性不足的地球科学群体的本科生提供研究经验。该项目建立在我们之前资助的工作基础上，开发了一种基于激光的工作（可调谐红外激光直接吸收光谱- TILDAS）仪器，用于快速精确测量CO2的团块同位素（例如，13C18O16O）。基本仪器已经构建，但需要在实际样品处理的稳定性和发展方面进一步改进，以生产可以在科学界广泛使用的仪器。与目前使用的质谱法相比，这种基于激光的测量方法具有主要优势，因为它的速度要快得多，只需20分钟的分析就可以达到所需的精度。小样本量（与最小的质谱仪系统相当，并且有进一步减少的潜力）和吞吐量的大幅增加将使地球化学家能够从精细分层的档案中提取以前无法获得的详细温度信息，例如贝壳、鱼耳石、洞穴、土壤碳酸盐、凝灰岩和石灰华。精细采样还将使研究人员能够更有效地解剖碳酸盐岩的成岩历史，解决与固态重排序相关的问题，研究地下沉积的带状裂缝充填胶结物，以及研究动力学和生命效应。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。