Minerals as recorders of Earth and planetary processes

矿物作为地球和行星过程的记录者

• 批准号: RGPIN-2016-06048
• 负责人: Flemming, Roberta
• 金额: $ 2.4万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=650848
• 关键词: Minerals; recorders; Earth; planetary; processes

Minerals record history, on Earth and other rocky bodies in the solar system. Minerals record their own formation conditions and subsequent events such as deformation, heating, and interaction with fluids, via their compositions, crystal structures, cation order-disorder and textural relationships. My long-term research goal is to investigate the evolution of Earth and other planetary bodies in our solar system, by examining minerals from selected locations on Earth as well as in meteorites and returned samples from the moon, and eventually from asteroids and Mars. My research will focus on two themes:***1 – Minerals as recorders of deformation:*** I will continue to lead the way in quantification of strain in minerals. I intend to quantify co-existing olivine and pyroxene in various settings, from the oldest solar system objects to evolved terrestrial samples. Studies will include chondritic meteorites as recorders of shock deformation on asteroids, martian meteorites as examples of deformation in a larger parent body, and mantle xenoliths as examples of deformation and dynamic recrystallization on Earth. Tandem grain size/strain measurements for olivine will elucidate mantle conditions. For olivine, pyroxene and terrestrial quartz, I aim to use 3D µXRD to compare deformation by meteorite impact (shock) against terrestrial tectonic deformation (strain), in order to discriminate between these effects. I will calibrate strain using minerals shocked to known shock pressures. These innovations will make µXRD a powerful probe of strain mechanism in Earth and planetary materials. ***2 – Minerals as recorders of temperature:*** I will interpret and quantify minerals as thermometers for the early solar system and terrestrial mantle rocks, by making systematic observations of cation distribution (order-disorder) for key mineral suites using NMR spectroscopy and diffraction methods, as well as energy models. Studying the co-existing minerals melilite and fassaite will reveal the cooling histories of Ca,Al-rich inclusions (CAIs) in meteorites, and of an unusual group of terrestrial alkaline ultramafic mantle rocks which are chemically similar to CAIs. In both cases these minerals record a complex history of crystallization and subsequent heating and metasomatism (fluid interaction). Parallel studies of these physically disparate, yet chemically similar, environments may elucidate the poorly-understood process of metasomatism. Independent estimates of temperature from spinel, fassaite and melilite in the same CAI would provide parent body cooling rate estimates, useful for modeling early solar system evolution.*** This research will place students at the forefront of current debates on the formation conditions and thermal evolution of early planetary bodies, the extent and variation of shock metamorphism in planetary materials, and the genesis of kimberlitic and other mantle-derived magmas.**

矿物记录了地球和太阳系其他岩石天体的历史。矿物通过其成分、晶体结构、阳离子有序无序和文本关系记录了它们自身的形成条件和随后的事件，例如变形、加热和与流体的相互作用。我的长期研究目标是通过检查地球上选定地点以及陨石中的矿物质以及从小行星和火星返回的样本来研究地球和太阳系其他行星体的演化。我的研究将集中在两个主题上：***1 – 矿物作为变形记录器：*** 我将继续引领矿物应变的量化，我打算量化各种环境下共存的橄榄石和辉石，从最古老的太阳系物体到演化的陆地样本，研究将包括作为小行星冲击变形记录器的球粒陨石、作为较大母体变形实例的火星陨石和地幔。作为地球上变形和动态重结晶的例子，橄榄石的串联晶粒尺寸/应变测量将阐明橄榄石、辉石和陆地石英的地幔条件，我的目标是使用 3D µXRD 来比较陨石撞击（冲击）与陆地构造造成的变形。变形（应变），为了区分这些影响，我将使用来校准应变。这些创新将使 µXRD 成为地球和行星材料应变机制的强大探针。 ***2 – 矿物作为温度记录器：*** 我将把矿物解释和量化为早期太阳的温度计。通过使用核磁共振波谱和衍射方法对关键矿物组的阳离子分布（有序-无序）进行系统观测，并研究共存矿物。黄长石和铁锰矿将揭示陨石中富含钙、铝的包裹体 (CAI) 的冷却历史，以及化学性质与 CAI 相似的一组不寻常的陆地碱性超镁铁质地幔岩石的冷却历史，在这两种情况下，这些矿物都记录了复杂的结晶历史。对这些物理上不同但化学上相似的环境的并行研究可能会阐明人们知之甚少的过程。对同一 CAI 中的尖晶石、铁橄榄石和黄长石的温度进行独立估计将提供母体冷却速率估计，有助于模拟早期太阳系演化。*** 这项研究将使学生处于当前关于形成的争论的前沿。早期行星体的条件和热演化、行星物质冲击变质作用的程度和变化，以及金伯利岩和其他地幔岩浆的成因。 **