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: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=616072
• 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体的历史。矿物通过其成分、晶体结构、阳离子有序无序和结构关系记录其自身的形成条件和后续事件，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和从月球返回的样本，并最终从小行星和火星返回的样本，研究地球和太阳系其他行星体的演变。我的研究将集中在两个主题： 1 -作为变形记录器的矿物： 我将继续在矿物应变量化方面发挥领导作用。我打算量化各种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。研究将包括南极陨石作为小行星冲击变形的记录器，火星陨石作为较大母体变形的例子，地幔捕虏体作为地球变形和动态重结晶的例子。橄榄石的串联粒度/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 µXRD来比较陨石撞击（冲击）与陆地构造变形（应变）的变形，以区分这些影响。我将使用受到已知冲击压力冲击的矿物质来校准应变。这些创新将使µXRD成为地球和行星材料应变机制的有力探针。 2.矿物作为温度记录器： 我将解释和量化矿物作为早期太阳系和地球地幔岩石的温度计，通过使用NMR光谱和衍射方法以及能量模型对关键矿物套件的阳离子分布（有序-无序）进行系统观察。研究共存矿物黄长石和fassaite将揭示冷却历史的钙，铝丰富的包裹体（CAIs）的陨石，和一个不寻常的组的陆地碱性超镁铁地幔岩石化学相似的CAIs。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作用知之甚少的过程。在同一CAI中对尖晶石、方长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，这对模拟早期太阳系演化很有用。 这项研究将使学生处于当前关于早期行星体的形成条件和热演化，行星材料中冲击变质作用的程度和变化，以及金伯利岩和其他幔源岩浆成因的辩论的最前沿。