Minerals as recorders of Earth and planetary processes

矿物记录了地球和太阳系中其他岩石天体的历史。矿物通过其成分、晶体结构、阳离子有序无序和结构关系记录自身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研究地球和太阳系中其他行星体的演化，方法是检查地球上选定地点的矿物质，以及月球上的陨石和返回的样本，最后是小行星和火星上的样本。我的研究将集中在两个主题上：***1 -矿物作为变形的记录者：***我将继续在矿物应变的量化方面处于领先地位。我打算量化在不同环境下共存的橄榄石和辉石，从最古老的太阳系物体到进化的地球样本。研究将包括球粒陨石作为小行星冲击变形的记录者，火星陨石作为更大母体变形的例子，地幔捕虏体作为地球上变形和动态再结晶的例子。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，我打算使用3DµXRD来比较陨石撞击（冲击）和陆地构造变形（应变）造成的变形，以便区分这些影响。我将使用受到已知冲击压力冲击的矿物来校准应变。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 -矿物作为温度记录者：***我将解释和量化矿物作为早期太阳系和陆地地幔岩石的温度计，通过使用核磁共振波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。通过对镁铝石和镁铝石共存矿物的研究，可以揭示陨石中富钙、富铝包裹体（CAIs）的冷却历史，以及一类与富钙、富铝包裹体化学性质相似的陆相碱性超镁铁质地幔岩的冷却历史。在这两种情况下，这些矿物都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。对这些物理上完全不同，但化学上相似的环境进行平行研究，可能会阐明鲜为人知的交代作用过程。对同一CAI中尖晶石、辉石和千晶石的独立温度估计将提供母体冷却速率的估计，这对模拟早期太阳系演化很有用。***这项研究将使学生置身于当前关于早期行星体的形成条件和热演化、行星物质中激波变质作用的程度和变化、金伯利岩和其他幔源岩浆的成因等争论的前沿

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.**