Chemical Evolution of High Temperature Silicic Magmas

9614322 Nekvasil在海洋和大陆热点环境和大陆裂谷地区的碱岩组似乎比更常见的拉斑岩来自更大的深度。因此，它们应该包含有关地幔的物理和化学条件以及导致热点形成和裂谷的过程的重要信息。通过对澳大利亚南威尔士南德瓦尔火山碱性玄武岩（夏威夷岩）分选过程中长石成分演化的实验测定，可以揭示这些过程。此外，其他实验将探讨三元长石适应压力和温度变化的反应机制。实验中使用的长石是玄武岩演化研究中合成的长石，以及来自拉勒米斜长岩杂岩西比尔正长岩的均质天然三元长石。

9614322 Nekvasil Alkalic rock suites in oceanic and continental hot spot environments and regions of continental rifting appear to come from greater depths than the more common tholeiites. Hence, they should contain important information regarding the physical and chemical conditions in the mantle as well as the processes that lead to hot spot formation and rifting. Elucidation of these processes may be revealed by experimental determination of the compositional evolution of feldspars during fractionation of an alkalic basalt (hawaiite) from the Nandewar Volcano, N.S.W. Australia. Additionally, other experiments will address the reaction mechanisms by which ternary feldspars adjust to changes in pressure and temperature. The feldspars utilized in these experiments are synthetic ones produced in the basalt evolution studies as well as homogenized natural ternary feldspars from the Sybille syenite of the Laramie Anorthosite Complex.