Formation Conditions of Refractory Inclusions and Chondrules in Chondritic Meteorites

球粒陨石含有46亿年前形成的太阳系中最早的固体物质。这些陨石主要由毫米大小的被称为球粒的颗粒和非常细粒度（亚微米）的基质组成。耐火夹杂物的尺寸为毫米到厘米，是第三个重要组成部分：被称为耐火夹杂物的物体包括富钙铝夹杂物（CAIs）。虽然我们知道球粒和一些cai在几个小时的时间尺度上经历了融化和冷却，在太阳系形成的前200万年里，我们不知道是什么过程导致了这种加热。模型的范围从撞击事件到尘埃原行星盘中的弓形激波。通过研究这些熔化物体的化学和同位素性质，我们可以对加热机制以及圆盘内不同物质储层的动态演化进行约束。本项目将通过对球粒陨石样品的岩石学研究与对难熔包裹体和球粒类似物的实验室实验相结合，研究难熔包裹体和球粒形成的加热机制。分析技术包括用于研究自然和实验样品的矿物学和质地的扫描电子显微镜（SEM），用于测量矿物化学成分的电子显微探针（EPMA）和用于测量单个颗粒同位素组成的二次离子质谱（SIMS）。实验将在一气氛气体混合炉中进行。

Chondrite meteorites contain the earliest solid material that formed within our Solar System, 4.6 billion years ago. These meteorites are predominantly made up of millimetre-sized particles known as chondrules, and very fine-grained (sub-micrometre) matrix. Refractory inclusions, millimetres to centimetres in size, are a third important component: objects named refractory inclusions include Calcium-Aluminium-rich Inclusions, or CAIs. Although we know that chondrules and some CAIs underwent melting and cooling on timescales of a few hours, within the first 2 million years of formation of the Solar System, we do not know what process was responsible for that heating. Models range from impact events to bow shock waves in the dusty protoplanetary disk. We can put constraints on the heating mechanism, as well as the dynamic evolution of different reservoirs of material within the disk, by studying the chemical and isotopic properties of these melted objects. This project will investigate the heating mechanism responsible for formation of refractory inclusions and chondrules, by combining petrologic studies of chondrite samples with laboratory experiments on refractory inclusion and chondrule analogues. Analytical techniques include scanning electron microscopy (SEM) for investigating mineralogy and textures of natural and experimental samples, electron microprobe (EPMA) for measuring the chemical compositions of minerals, and secondary ion mass spectrometry (SIMS) for measuring isotope compositions in individual grains. Experiments will be conducted in a one-atmosphere gas-mixing furnace.