Experimental Studies on Melting (Mg, Fe)O Ferropericlase

熔融(Mg,Fe)O铁镁石酶的实验研究

• 批准号: 1551348
• 负责人: Kanani Lee
• 金额: $ 33.68万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-15 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1551348&HistoricalAwards=false
• 关键词: Experimental; Studies; Melting; Mg; Fe

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. 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. Experiments conducted at pressures corresponding to depths greater than ~1200 km suggests that an ideal solid solution behavior becomes more eutectic-like with increasing pressure. 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. Additionally, this experimental investigation will help constrain current temperatures of the Earth by estimating the temperatures at the core-mantle boundary.

地球和其他行星在我们自己和其他太阳系中的起源和随后的演变取决于几个因素，包括原始成分和组成相的熔融行为。然而，对地幔熔化温度的估计仍然存在争议和难以捉摸，地幔占地球体积的四分之三以上，质量的近三分之二。地幔熔化和凝固的条件对于理解成分的不均匀性特别重要，这种不均匀性限制了深部结构和混合，对于推断地球的热化学演化至关重要，从行星吸积和岩浆海洋到大陆生长，海洋和大气的形成，以及核幔边界的当前状态。地幔中最丰富的矿物之一铁方镁石（Mg，Fe）O在高压下的熔融行为将检验地球形成的假设，并阐明深部地幔的地球化学。 在深度大于~1200 km的压力下进行的实验表明，随着压力的增加，理想的固溶体行为变得更像共晶。 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、成分和结构进行二维绘图来研究这些实验，这些样品是由激光加热的金刚石砧室产生的，目的是确定熔化发生的条件及其随后对熔化区域和周围区域的成分和形态的影响。 此外，这项实验研究将有助于通过估计核幔边界的温度来限制地球目前的温度。