EAGER: Towards a Paleoproxy of Stratospheric Chemistry Using Meteorite Fusion Crusts

EAGER：利用陨石聚变结壳探索平流层化学的古代理

• 批准号: 1612532
• 负责人: Ryan Ogliore
• 金额: $ 5.77万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-10-01 至 2016-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1612532&HistoricalAwards=false
• 关键词: EAGER; Towards; Paleoproxy; Stratospheric; Chemistry

There are many ways of reconstructing past environments at the Earth's surface, but reconstructing past conditions in the upper atmosphere has not been possible because of the lack of physical samples from these altitudes. While modern Earth System Models simulate climate dynamics and atmospheric chemistry from the Earth's surface to the stratosphere and beyond, there has been no way to ground-truth the results for the upper atmosphere for conditions that are different from those at present. This study, a collaboration between a cosmochemist and a climate dynamicist, investigates the feasibility of reconstructing upper atmosphere temperature and composition during past climates using high precision isotopic measurements of the fusion crust of meteorites. Specifically, the work tests the hypothesis that magnetite in the fusion crust of iron meteorites records the isotopic composition of O2 in the atmosphere at the time and altitude that the fusion crust formed, which in turn is a proxy for ozone concentration (a mass-independent signature) as well as variations in the Dole Effect or other mass-dependent stratospheric processes. The work takes advantage of existing collections of meteorites. If this pilot project is successful, the fusion crust paleo-atmosphere proxy could be applied to the vast collection of Antarctic meteorites, which spans the past 3 million years, and could provide tests of Earth System Model results.

有很多方法可以在地球表面重建过去的环境，但是由于缺乏这些高度的物理样本，因此无法重建上层大气中的过去条件。尽管现代地球系统模型模拟了从地球表面到平流层及以后的气候动力学和大气化学反应，但对于目前不同的条件，上层大气的结果无法实现。这项研究是宇宙学家与气候动态主义者之间的合作，研究了在过去气候期间使用高精度的同位素测量值对陨石的融合壳进行重建上层大气温度和组成的可行性。具体而言，这项工作检验了以下假设：铁陨石融合中的磁铁矿记录了融合外壳形成的大气中O2的同位素组成，这反过来又是臭氧浓度的代理（质量独立的签名）的代理（一种质量独立的签名）以及Dole效应或其他质量依赖性依赖性依赖性的依赖性的变化。这项工作利用了现有的陨石集合。如果该试点项目成功，则可以将融合式古老的大气代理代理应用于大量的南极陨石集合，该陨石跨越了过去300万年，并可以提供地球系统模型结果的测试。