CSEDI Collaborative Research: A Coupled Geodynamic-Geochemical Study of the Hawaiian Plume

EAR-0002629 Donald J.DePaolo这项CSEDI建议将侧重于开发夏威夷羽流的地球动力学-地球化学耦合模型，使研究人员能够解决与岩浆成分的空间和时间变化有关的问题。从夏威夷岛链研究和夏威夷科学钻探项目(HSDP)钻芯获得的化学数据将为这一建模提供限制。该项目将重点回答这样一个问题：“在夏威夷火山中观察到的岩石学、地球化学学和同位素特征能否用自洽的地球动力学-地球化学模型中产生的羽流熔体来解释？”特别是，研究人员将确定沿岛链喷发的岩浆成分变化是否与我们对羽流动力学和地幔熔融的理解一致。在这项提议的一年时间框架内，目标将是将最近开发的Ribe和Christensen(1999)的三维可变粘度羽流模型与痕量元素化学和铀系列不平衡的计算相结合。他们还将开发一种新的主要元素参数化，专门为解决夏威夷羽流中的融化问题而设计。这一模型的开发将是一个正在进行的项目；算法将被设计为随着新的实验数据的获得而更新。通过反复改进羽流模型和岩浆化学计算，并将模型计算与观测到的岩浆成分和喷发速率进行比较，这项研究将进一步加深我们对地幔热柱动力学的理解，并确定夏威夷岛链以下地幔的熔融条件。

EAR-0002629Donald J. Depaolo This CSEDI proposal will focus on developing a coupled geodynamic-geochemical model of the Hawaiian plume that will allow the investigators to address questions relating to the spatial and temporal variations in magma compositions. Chemical data available from studies in the Hawaiian island chain and from the Hawaiian Scientific Drilling Project (HSDP) drill core will provide constraints for this modeling. The project will focus on answering the question: ``Can the petrological, geochemical, and isotopic characteristics observed among the Hawaiian volcanoes be explained in terms of plume derived melts from a self-consistent geodynamic-geochemical model?''. In particular, the investigators will determine whether the compositional changes in magmas erupted along the island chain are consistent with our understanding of plume dynamics and mantle melting. During the one-year time frame of this proposal, the goals will be to couple the recently developed 3-D variable viscosity plume model of Ribe and Christensen (1999) with calculations of trace-element chemistry and uranium series disequilibria. They will also develop a new major-element parameterization specifically designed to address melting in the Hawaiian plume. The development of this model will be an ongoing project; the algorithm will be designed to be updated as new experimental data become available. By iteratively refining the plume model and calculations of magma chemistry, and by comparing the model computations to the observed magma compositions and eruption rates, this research will further our understanding of the dynamics of the mantle plume and determine the melting conditions in the mantle beneath the Hawaiian island chain.