Effect of melt densification on minor element incorporation at Earth’s lower mantle conditions

We will extend our study on the pressure and temperature induced structural changes around Sr and Y contained silicate melts and glasses relevant to magmatic processes in the deep Earth. We plan to extend our previous work on simplified glass compositions. In this follow-up, we will focus on the naturally most relevant basaltic composition. We will investigate in-situ at high P/T conditions of the Earth’s mantle the local structural environment of these cations, both in the glass and in the melt using a laser heated diamond anvil cell combined with X-ray absorption spectroscopy. These data will allow identifying effects of pressure-induced structural changes of the main silicate network onto the coordination of these cations that represent geochemically important trace elements as well as network-modifying cations. These data will provide unprecedented insights on the structural interplay between network-forming and NM-elements of melts throughout Earth’s mantle conditions.

本研究将拓展针对含锶（Sr）与钇（Y）硅酸盐熔体及玻璃的压力与温度诱导结构变化的相关研究，该研究对象与地球深部岩浆作用过程紧密相关。我们计划基于此前针对简化玻璃组分的研究开展后续工作。在本次后续研究中，我们将聚焦于自然体系中最具代表性的玄武岩组分。我们将采用结合激光加热金刚石对顶砧（laser heated diamond anvil cell）与X射线吸收光谱（X-ray absorption spectroscopy）的实验系统，在地球幔域的高温高压条件下，原位表征上述阳离子在玻璃及熔体中的局域结构环境。通过这些数据，我们能够明确主硅酸盐网络的压力诱导结构变化对作为地球化学关键微量元素与网络修饰阳离子（network-modifying cations）的上述阳离子配位环境所产生的影响。这些数据将为厘清地球全幔温压条件下熔体中网络形成体与网络修饰元素（network-modifying elements，简称NM元素）间的结构相互作用提供前所未有的认知。