Experimental Studies on Melting (Mg, Fe)O Ferropericlase

地球和其他行星在我们自己和其他太阳系的起源和后来的演变是由几个因素决定的，包括原始成分和组成相的熔化行为。然而，对占地球体积四分之三以上、质量近三分之二的地幔的融化温度的估计仍然存在争议和难以捉摸。地幔融化和凝固的条件对于理解其成分的非均质性尤其重要，它限制了深部结构和混合，对推断地球的热化学演化至关重要，从行星吸积和岩浆海，到大陆生长，海洋和大气的形成，以及核幔边界的现状。目前，地幔几乎完全是固态的，但并非一直如此。在地球形成的过程中，地幔很可能是完全熔融的——一个岩浆海洋——然后在冷却时开始凝固。地幔是如何结晶的，即从顶部、底部还是介于两者之间的某个地方，目前还不清楚。在地核-地幔边界处，至少在一些小口袋里，存在融化的证据是强有力的，因为它靠近地表。研究地幔中最丰富的矿物之一铁长石（Mg, Fe）O在高压下的熔融行为，将检验关于地球形成的假设，并阐明深部地幔的地球化学。此外，这项实验研究将有助于通过估算地核-地幔边界的温度来限制地球当前的温度。这些实验将通过对放置在地球早期地幔的极端高压、高温条件下的样品材料的温度、成分和质地进行二维测绘来进行研究，这些样品材料是由激光加热的金刚石砧细胞产生的，目的是确定熔化发生的条件及其对熔融区域和周围区域的成分和形态的后续影响。

The origin and subsequent evolution of the Earth and other planets in our own and other solar systems is dictated by several factors including original composition and the melt behavior of the constituent phases. However, estimates of the melting temperature of Earth's mantle, which comprises more than three-quarters of the Earth's volume and nearly two-thirds of its mass, remain controversial and elusive. The conditions at which the mantle melts and solidifies is especially important for understanding compositional heterogeneity, which constrains deep structure and mixing and is crucial for inferring the thermo-chemical evolution of the Earth, from planetary accretion and the magma ocean, to continental growth, the formation of the oceans and atmosphere, and the current state of the core-mantle boundary. Currently the mantle is nearly entirely solid, but it has not always been this way. During the formation of the Earth, the mantle was likely completely molten - a magma ocean - before it began to solidify as it cooled. How the mantle crystallized, i.e., from the top, the bottom, or somewhere in between, is unknown. Evidence for melt at the core-mantle boundary, at least in pockets, is strong, as it is near the surface. Investigating the melt behavior of one of the most abundant minerals in the mantle, ferropericlase (Mg, Fe)O, at high pressures will test hypotheses on Earth's formation and elucidate the geochemistry of the deep mantle. Additionally, this experimental investigation will help constrain current temperatures of the Earth by estimating the temperatures at the core-mantle boundary. The experiments will be studied by 2-dimensional mapping of temperature, composition and texture of sample materials placed under the extreme high-pressure, high-temperature conditions of the Earth's early mantle as produced by a laser-heated diamond-anvil cell, in order to identify the conditions at which melting occurs and its subsequent influence on the composition and morphology of the molten and surrounding regions.