Collaborative Research: Geochemistry and Whole Mantle Convection

货车Keken，Haurin-0229962，0229755研究者对洋壳的生成和再循环在地球化学不均匀性形成中的作用感兴趣，洋壳的形成是一个基本的分异过程，它导致微量元素和体相组成的明显变化。密度和流变学的相关变化对地幔动力学和地幔混合有重要影响。我们的主要假设是大洋地壳的形成和再循环可以解释大部分地球化学观测结果。本项目的中心目标是研究组成密度在保持地球化学非均匀性中的作用。作为研究人员假设检验方法的一部分，他们将解决以下问题： 1)洋壳的再循环如何影响地幔化学？ 2)惰性气体和亲岩同位素比值之间的关系是什么？ 3)地球形成过程中的大尺度分异是否可以解释目前观察到的不均匀性？ 研究小组将结合地球动力学和地球化学模型来回答这些问题。这提供了一个很好的工具来测试conceptualideas量化地幔混合，分馏，分化和脱气的影响。这种方法是基于先前建立的货车Keken，Ballentine和Hauri之间的合作。以前的模型将通过模拟洋壳形成、加入亲石同位素和显著提高空间和时间分辨率来改进。货车Keken和一名研究生将负责模型改进和动力学计算，而Hauri和Ballentine将指导假设检验方法并协助地球化学模拟。合作方面是这一建议的重要组成部分。 该项目将导致更好地了解负责我们星球的热和化学演变的过程。它将帮助开发基本的动力学建模工具，并提供跨学科的整合，国际合作，以及对学生进行定量地球物理学和地球化学方面的教育。

Van Keken, HauriEAR-0229962, 0229755The investigators are interested in the role that the generation and recyclingof oceanic crust plays in the formation of geochemical heterogeneity.The formation of oceanic crust is a fundamental differentiation process thatcauses distinct variations in trace element and bulk composition. The relatedvariations in density and rheology have important consequences for mantledynamics and mantle mixing. Our main hypothesis is that the formation andrecycling of oceanic crust can explain a vast proportion of the geochemicalobservations. The central goal of this project is to study the role thatcompositional density plays in preserving geochemical heterogeneity.As part of the investigators' hypothesis testing approach they will address following questions: 1) How does the recycling of oceanic crust affect mantle chemistry? 2) What are the relationships between noble gas and lithophile isotope ratios? 3) Is it possible that the large-scale differentiation during Earth'sformation accounts for the presently observed heterogeneity? The team will use a combination of geodynamical and geochemical modeling toanswer these questions. This provides an excellent tool to test conceptualideas by quantifying the effects of mantle mixing, fractionation,differentiation, and degassing. The approach is based on previously establishedcollaboration between Van Keken, Ballentine and Hauri. Previous models will beimproved by the modeling of oceanic crust formation, incorporation oflithophile isotopes, and significantly higher spatial and temporal resolution.Van Keken and a graduate student will be responsible for the model improvementsand dynamical computations, while Hauri and Ballentine will guide the hypothesistesting approach and aid the geochemical modeling. The collaborative aspects arean essential component of this proposal. This project will lead to a better understanding of the processes that areresponsible for the thermal and chemical evolution of our planet. It will aidin the development of essential dynamical modeling tools and providecross-disciplinary integration, international collaboration, and educationof students in quantitative geophysics and geochemistry.