High Pressure Phase Equilibrium Studies Bearing on the Generation and Crystallization of Basaltic Magmas

这个多年来一直保持不变的研究计划的长期目标是建立一个系统收集的相平衡数据体系，对玄武岩的起源和地幔形成地壳施加越来越严格的限制。为了推广结果，并在一个重要的压力范围内建立更全面的数据体系，建议使用活塞-圆柱体装置确定15、25和30kbar时的相关系以及Na2O对熔化关系的影响。这些数据将为(1)原始大洋中脊玄武岩的起源，(2)夏威夷群岛原始拉斑玄武岩的成分、生成深度和熔融百分比提供新的限制，以及(3)俯冲带高铝玄武岩的起源。此外，还建议用阿尔伯塔大学的MA-8装置研究压力高达250kbar的Mg_2SiO_4-SiO_2系统的熔化关系。这项研究将对地球早期历史上的超高压岩浆作用产生影响。

The long-term objective of this research program, which has remained the same over the years, is to develop a systemically collected body of phase equilibrium data that imposes progressively tighter constraints on the origin of basalt and the formation of the earth's crust from the mantle. In order to generalize results and to develop a more comprehensive body of data in an important pressure range, it is proposed to determine, using a piston-cylinder apparatus, the phase relationships at 15, 25, and 30 kbar and the effect of Na2O on melting relationships. The data would provide new constraints on (1) the origin of primary mid-ocean ridge basalts, (2) the composition, depth of generation, and percent melting of primary tholeiitic magmas in the Hawaiian Islands, and (3) the origin of high-alumina basalts in subduction zones. In addition, it is proposed to study melting relations in the system Mg2SiO4-SiO2 up to pressures of 250 kbar using an MA-8 apparatus at the University of Alberta. This study would bear on very high pressure magmatic processes in the early history of the earth.