俯冲带弧岩浆演化是形成大陆壳的主要过程。铁是地壳中丰度最高的变价元素，全铁(FeT)及Fe3+和Fe2+在矿物与熔体之间的分配系数是理解和认识弧岩浆钙碱性演化(铁亏损)趋势和氧逸度变化规律的关键。但目前关于弧岩浆结晶分异过程中主要铁镁质矿物中Fe3+和Fe2+分配系数的研究还十分缺乏。本项目拟开展在氧逸度控制条件下的高温高压实验；系统研究氧逸度、温度、压力、矿物和熔体成分等物理化学因素对铁镁矿物−熔体间FeT分配系数的影响；使用同步辐射μ-XANES技术测定实验产物中熔体的Fe3+/FeT比值；结合不同氧逸度条件下FeT的分配系数和熔体Fe3+/FeT比值，通过拟合得到橄榄石、斜方辉石、单斜辉石、角闪石、石榴子石和铁钛氧化物等矿物的Fe3+和Fe2+分配系数及其随物理化学因素变化的规律，为阐明弧岩浆钙碱性(铁亏损)演化趋势和氧逸度变化规律的控制因素提供关键制约。

Continental crust forms by the evolution of arc magmas in subduction zones. As the most abundant multivalent element in the crust, partitioning behaviors of Fe (i.e. Fe3+ and Fe2+) are critical in understanding the calc-alkaline differentiation (iron depletion) trend and how the oxygen fugacity (fO2) varies during magma differentiation. But hindered by the analytical techniques, partition coefficients of Fe3+ and Fe2+ pertinent to the differentiation conditions of arc magmas are still rare. In the present study, we will perform high temperature and pressure experiments with fO2 well-buffered; investigate the effects of fO2, temperature and pressure on the partitioning of FeT (bulk iron); analyze Fe3+/FeT ratio of the quenched melt using μ-XANES; then obtain the partition coefficients of Fe3+ and Fe2+ by combining the bulk iron partition coefficients and the Fe3+/FeT ratios of the quenched melts. Hence, we can determine Fe3+ and Fe2+ partition coefficients for olivine, orthopyroxene, clinopyroxene, amphibole, garnet and Fe-Ti oxides at P−T conditions pertinent to arc magma differentiation. The results will found the basis for further understanding of the calc-alkaline differentiation trend and the fO2 variation during arc magma differentiation.