The K' of Highly Compressible Silicate Liquids: An Experimental Study

模拟地幔深部部分熔融过程的主要挑战是缺乏关于高压下岩浆液体密度的信息。最大的不确定性是压力对熔体可压缩性的依赖(K0‘=dK0/dp)，以及K0’如何随熔体组成变化。这项建议的目标是严格限制四种硅酸盐(NaAlSi3O8、CaTiSiO5、Na2Si2O5、K2Si2O5)和三种碳酸盐(Li2CO3、Na2CO3、K2CO3)液体的K0‘值，这些液体在一巴(1600℃时，KT，0在4到17 Gpa之间)是高度可压缩的。这些结果与文献中的K_0和K_0‘数据相结合，将对硅酸盐液体的K_0’与其一巴体积弹性系数(K_0)成反比的假设提供可靠的检验。如果这一新假设得到证实，它将允许从岩浆液体的一巴体积模数估计K0‘，对于这一点，已经有了很好的校准模型。相反，如果K0和K0‘之间的假设关系不成立，硅酸盐和碳酸盐液体的新K0’数据将大大增加K0‘独立于K0已知的液体的现有数据集。我们将使用熔化曲线分析结合高质量的相平衡实验来确定液体K0‘。该项目将为两名女研究生提供X射线衍射、傅里叶变换红外光谱和电子探针分析方面的培训，以及包括冷封压力容器和活塞-圆筒装置在内的高压和高温设备。它还将为他们提供晶体-液体平衡的热力学计算方面的教育，以及他们的结果对岩浆作用和火山作用研究的重要性。他们将发展的技能将为他们在地球科学或高科技材料行业的职业生涯做好同样好的准备。

LangeEAR-0310079A major challenge to modeling the partial melting process at deep mantle depths is the lack of information on the density of magmatic liquids at high pressure. The largest uncertainty is with the pressure dependence on melt compressibility (K0' = dK0/dP), and how K0' varies with melt composition. The goal of this proposal is to tightly constrain values of K0' for four silicate (NaAlSi3O8, CaTiSiO5, Na2Si2O5, K2Si2O5) and three carbonate (Li2CO3, Na2CO3, K2CO3) liquids that are highly compressible at one bar (KT,0 between 4 and 17 GPa at 1600 degrees C). These results, when combined with K0 and K0' data in the literature will provide a robust test of the hypothesis that the K0' of a silicate liquid is inversely correlated with its one-bar bulk modulus (K0). If this new hypothesis is verified, it will allow the K0' of magmatic liquids to be estimated from their one-bar bulk modulus, for which there are well-calibrated models. Conversely, if the postulated relation between K0 and K0' is shown not to hold, the new K0' data for silicate and carbonate liquids will substantially augment the existing data set for liquids for which K0' is known independently of K0. The method that we will use to determine liquid K0' is fusion curve analysis, combined with high-quality phase-equilibrium experiments. This project will provide training to two female graduate students in X-ray diffraction, FTIR spectroscopy, and electron microprobe analysis, as well as with high-pressure and high-temperature equipment including a cold-seal pressure vessel and piston-cylinder apparatus. It will also provide them with an education in thermodynamic calculations of crystal-liquid equilibria, and on the importance of their results to studies of magmatism and volcanism. The skills that they will develop will prepare them equally well for a career in either the earth sciences or the high-tech materials industry.