Isotopic and Chemical Investigation of Chromatographic Effects During Melt-Mantle Interaction

这个项目是通过色谱理论的扩展来完善熔体通过地幔迁移过程中的化学反应模型。除了之前工作人员概述的色谱原理外，我们还将考虑孔隙度、熔体分数和矿物学变化作为熔体-地幔反应程度和类型的函数。为了验证模型的预测，我们建议从厚碱性玄武岩序列中获得一个独特的数据集。该模型的初步实现表明，至少有三种不同的化学特征，以寻找其碱性玄武岩序列。在以前发表的数据中，这些趋势被归因于地幔交代作用和/或微量地幔相（如锆石或金红石）的存在。初步评价表明，色谱模型可能是一个同样可行的替代假设，以解释某些碱性玄武岩趋势。为了对该模型进行更明确的测试，我们启动了一个分析程序，以获得夏威夷和加那利群岛上选定的碱性玄武岩喷口的同位素和微量元素逐流特征。

9628674 Nelson This project is to refine models of chemical reactions during melt migration through the mantle sing an extension of chromatographic theory. In addition to the chromatographic principles outlined by previous workers, we will include consideration of changing porosity, melt fraction and variable mineralogy as a function of extent and type of melt-mantle reaction. To test the model predictions, we propose to obtain a unique data set from thick alkalic basalt sequences. Initial implementation of this model suggests at lease three distinct chemical characteristics to search for its alkalic basalt sequences. In published data, previously, these trends have been ascribed to mantle metasomatism and/or presence of trace mantle phases such as zircon or rutile. Preliminary evaluation suggests that the chromatographic model may be an equally viable alternative hypothesis to explain certain alkalic basalt trends. The need for a more definitive test of the model motivates an analytical program to obtain isotopic and trace element flow-by-flow characterization of selected alkalic basalt vents on Hawaiian and Canary Islands.