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中其他岩石天体的历史。矿物通过其组成、晶体结构、阳离子有序-无序和结构关系，记录了它们自己的形成条件和随后的事件，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来自地球上选定地点的矿物，以及陨石和从月球返回的样本，最终从小行星和火星返回矿物，来研究地球和我们太阳系中其他行星的演化。我的研究将集中在两个主题上：*1-作为变形记录器的矿物：*我将继续在量化矿物应变方面走在前列。我打算量化在不同环境中共存的橄榄石和辉石，从最古老的太阳系物体到进化的陆地样本。研究将包括球粒陨石作为小行星冲击变形的记录器，火星陨石作为更大母体变形的例子，以及地幔捕捉体作为地球变形和动态重结晶的例子。橄榄石的连续粒度/应变测量将阐明地幔条件。对于橄榄石、辉石和陆地石英，我的目标是使用3D微X射线衍射仪比较陨石撞击(冲击)引起的变形和陆地构造变形(应变)，以区分这些影响。我会用冲击到已知冲击压力的矿物来校准张力。这些创新将使µXRD成为研究地球和行星材料应变机制的强大探测器。*2-矿物作为温度记录器：*我将通过使用核磁共振光谱和衍射方法以及能量模型对关键矿物组的阳离子分布(有序-无序)进行系统观察，将矿物解释并量化为早期太阳系和地球地幔岩石的温度计。研究黄长石和法萨石的共生矿物将揭示陨石中富钙铝包裹体(CAI)的冷却历史，以及一组化学上与CAI相似的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，这些矿物记录了结晶和随后的加热和交代(流体相互作用)的复杂历史。对这些物理上不同但化学上相似的环境进行平行研究，可能会阐明人们对交代过程知之甚少的过程。在同一计算机辅助教学中对尖晶石、方沸石和黄长岩的温度进行独立估计将提供母体冷却速度估计，这对模拟早期太阳系演化很有用。*这项研究将使学生站在当前争论的前沿，这些争论包括早期行星体的形成条件和热演化，行星物质中冲击变质的程度和变化，以及金伯利岩和其他地幔岩浆的成因。**