Experimental Investigations of Melting Processes in the Subcontinental Mantle

这项研究将调查导致地球上地幔岩浆生成的过程。采用实验岩石学方法，在高温（1200 ~ 1700℃）和高压（2 ~ 5gpa）下，在无水和不饱和条件下进行熔融实验。用于实验的样品将是交代地幔模拟成分和天然玄武岩成分。将进行两种类型的实验。第一组实验将产生饱和地幔矿物（橄榄石、正辉石、斜辉石和石榴石）的熔体，熔体成分的变化将用于发展预测分析模型，预测次大陆地幔熔体产生的条件。第二组实验将使用从一系列大陆构造环境（青藏高原、内华达山脉和墨西哥后弧）中选择的自然发生的玄武岩岩浆，并将确定这些环境中熔体产生的条件。根据这些结果，将建立模型来评估压力、温度、水和地幔体积组成变化对地幔熔融反应的控制。这些实验和模型将对次大陆岩石圈的稳定、大陆之下的地幔流动和熔融以及通过地幔的挥发物通量的影响等过程提供限制。

GroveEAR-0073766The research will investigate the processes that lead to the generation of magmas in the earth's upper mantle. The methods of experimental petrology will be used and melting experiments will be performed at elevated temperature (1200 - 1700 oC) and pressure (2 - 5 GPa) under anhydrous and H2O-undersaturated conditions. Samples used for the experiments will be metasomatized mantle analog compositions and natural basalt compositions. Two types of experiments will be performed. The first set of experiments will produce melts saturated with mantle minerals (olivine, orthopyroxene, clinopyroxene and garnet) and the variation in composition of the melt will be used to develop predictive analytic models for the conditions of melt generation in the subcontinental mantle. The second set of experiments will use selected naturally occurring basaltic magmas from a range of continental tectonic settings (the Tibetan Plateau, Sierra Nevada and Mexican back arc) and will determine the conditions of melt generation in these settings. From these results models will be developed that evaluate the controls of pressure, temperature, H2O and variations in mantle bulk composition on mantle melting reactions. The experiments and models will provide constraints on the processes of stabilization of sub-continental lithosphere, mantle flow and melting beneath continents and the influence of the flux of volatiles through the mantle.