A Thermal-Mechanical and Hafnium Isotope View of the Interplay Between Continental Extension and Magmatism -The Death Valley Volcanic Field and Adjacent Volcanic Sequences

9506612约翰逊拟议的工作将开发新的热和机械熔融模型来解释大陆伸展期间发生的地幔动力学，并将这些与死亡谷火山区和邻近地区伸展相关熔岩（ERL）的化学，同位素和时间演化的新观测联系起来。 最近的工作对以前提出的地壳大规模伸展期间壳幔演化的简单模型提出了质疑。 初步的同位素数据，包括铪同位素分析，提供了重要的限制古代和现代的熔融，交代和耗尽事件的深度，这些数据将被用来约束热力学模型。 在死亡谷的大型和高度延伸的火山场提供了一个特殊的机会，以限制和评估地幔的伸展热/熔融模型。

9506612 Johnson The proposed work will develop new thermal and mechanical melting models to explain the mantle dynamics that occur during continental extension, and tie these to new observations on the chemical, isotopic, and temporal evolution of extension related lavas (ERL) in the Death Valley volcanic field and adjacent areas. Recent work has cast doubt on simple, previously proposed models of crust-mantle evolution during large-scale extension of the crust. Preliminary isotope data, including Hf isotope analyses, provide important constraints on the depths of ancient and modern melting, metasomatism, and depletion events, and these data will be used to constrain thermal-mechanical models. The large and highly extended volcanic field at Death Valley provides an exceptional opportunity to constrain and evaluate extensional thermal/melting models of the mantle.