Chemical Evolution of High-Temperature Silicic Magmas

将继续对从玄武岩到流纹岩的天然碱性岩浆进行模拟逐步分离结晶的实验，这些岩浆分布在世界各地的海洋岛屿和大陆热点及裂谷地区，既有火山岩，也有深成岩。 这些实验将确定，如果晶体分馏可以发挥主导作用，在这些套房中产生的岩浆成分的多样性，如果是这样，在压力，溶解挥发分含量和氧逸度的条件下，这种分馏可能已经发生。 这些信息对于限制地幔和下地壳的热分布和成分分布以及一般的岩浆多样化过程是非常宝贵的。此外，由于富硅质熔岩的石英过饱和碱性套件是高度挥发性丰富，这种挥发物在火山爆发性中发挥了重要作用，实验数据的含水矿物分馏过程中的岩浆挥发物含量的增加是直接适用于潜在的火山灾害的评价。

NekvasilEAR-0000926Experiments simulating step-wise fractional crystallization will be continued on natural alkalic magmas ranging from basalts to rhyolite that are found world-wide on ocean islands and in continental hotspot and rifted regions as both volcanic and plutonic suites. These experiments will determine if crystal fractionation can play a dominant role in generating the compositional diversity of magmas in such suites, and if so, under which conditions of pressure, dissolved volatile content, and oxygen fugacity this fractionation may have taken place. Such information is invaluable for placing constraints on the thermal and compositional profiles of the mantle and lower crust and on magma diversification processes in general. Furthermore, since silica-rich lavas of quartz-oversaturated alkalic suites are highly volatile-rich and such volatiles play a major role in volcanic explosivity, experimental data on the increase of magmatic volatile content during fractionation of water-bearing minerals is directly applicable to the evaluation of potential volcanic hazards.