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

提出的工作将发展新的热和机械熔融模型，以解释大陆伸展期间发生的地幔动力学，并将这些模型与对死亡谷火山场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察联系起来。最近的研究对简单的、先前提出的地壳在大规模伸展期间的地壳-地幔演化模型提出了质疑。初步的同位素数据，包括Hf同位素分析，对古代和现代熔融、交代和枯竭事件的深度提供了重要的约束，这些数据将用于约束热力学模型。死亡谷的大而高度伸展的火山场为约束和评估地幔的伸展热/熔融模式提供了一个绝佳的机会。

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.