ABR: Experimental Studies of Hydrous Mantle Melting

这个项目的重点是了解地球是如何？S地幔在俯冲带融化。水是弧火山喷发的俯冲带岩浆形成的关键成分，弧火山形成于俯冲的海洋板块之上。这项研究将使用实验岩石学来了解当水参与熔融过程时岩浆是如何形成的。实验将包括融化的岩石(地球？在水的存在下，温度和压力相当于火山链以下深处所经历的温度和压力。关于水是如何影响地幔熔融产生的温度和化学成分，我们所知甚少。通过了解水？对温度、熔体成分和岩浆生成过程的化学反应的影响，我们将获得关于地球在哪里以及如何形成的新的基本知识。美国大陆地壳是经过地质时期形成的。这一新知识将通过提供一个定量框架来理解地球上45亿年的水循环，从而推进基础科学。年代的历史。这一基于成就的更新要求支持一个实验岩石学研究项目，该项目将量化水对俯冲带融化过程的影响。实验将系统地研究(1)1.6 ~ 2.8 GPa范围内的水-不饱和地幔熔融和(2)1.2 GPa范围内深部地幔熔融与浅层地幔围岩的水-不饱和反应。目前对1.6-2.8 GPa压力范围内的水熔过程知之甚少，本实验将为该压力范围内的水熔过程提供新的信息。本文提出的深部地幔熔体与浅层地幔围岩之间的反应实验将是首次在0.5 ~ 2 GPa压力下进行的含水反应实验。这些实验将使我们能够定量地了解地幔楔内部反应的影响，这一过程已得到广泛承认，但目前还缺乏实验探索。这两组实验的目标是评估H2O对熔体成分的影响，并利用新数据建立地幔熔融的定量模型以及亚弧地幔中熔融-岩石反应的模型。在俯冲带中，水在地幔和地壳中流动的岩浆过程对于理解地球过去45亿年的化学演化具有重要意义。拟议的工作将为理解水如何影响地球的化学成分提供定量基础。S地幔和地壳。实验数据将用于开发预测自然原始熔岩的温度、水含量和融化压力的模型，并将与地球科学界共享。实验研究的结果还将有助于开发软流圈地幔与俯冲板块之间流动耦合的更好的地球动力学模型，并提供通过地幔楔体的熔融运输物理过程的约束条件。

This project focuses on understanding how the Earth?s mantle melts in subduction zones. H2O is a key ingredient in the formation of subduction zone magmas that erupt at arc volcanoes, volcanoes that form above subducted oceanic plates. This study will use experimental petrology to understand how magmas are formed when H2O is involved in the melting process. The experiments will consist of melting rock (the Earth?s mantle) in the presence of H2O at the temperatures and pressures equivalent to those experienced at depth below the volcanic chains. Very little is known about how H2O influences the temperature and chemical compositions produced by mantle melting. By understanding water?s influence on the temperature, melt composition and chemical reactions of this magma generation process, we will gain new fundamental knowledge of where and how the Earth?s continental crust has been generated through geologic time. This new knowledge will advance basic science by providing a quantitative framework for understanding the recycling of water through the Earth over the 4.5 billion years of our planet?s history.This Accomplishment Based Renewal requests support for a program of experimental petrology studies that will quantify the influence of water on melting processes in subduction zones. The experiments will systematically investigate (1) H2O-undersaturated mantle melting from 1.6 to 2.8 GPa and (2) H2O-undersaturated reaction of deeper mantle melts with shallower mantle wall rock at 1.2 GPa. Very little is known about hydrous melting in the pressure range of 1.6-2.8 GPa, so the experiments will provide new information on the process of hydrous melting in this pressure range. The proposed reaction experiments between deeper mantle melt and shallower mantle wall rock will be the first hydrous reaction experiments ever performed at pressures between 0.5 and 2 GPa. These experiments will allow a quantitative understanding of the effects of reaction within the mantle wedge, a process that is widely acknowledged but one that currently lacks experimental exploration. For both sets of experiments, the goal is to assess the influence of H2O on melt composition and to use the new data to develop quantitative models for mantle melting as well as models of melt-rock reaction in the sub-arc mantle. The magmatic processes that flux H2O through the mantle and crust in subduction zones are of fundamental importance for understanding the chemical evolution of the Earth over the last 4.5 billion years. The proposed work will provide a quantitative basis for understanding how H2O has influenced the chemical composition of the Earth?s mantle and crust. The experimental data will be used to develop models for predicting temperature, H2O content and pressure of melting for natural primitive lavas, which will be shared with the geosciences community. The results of the experimental study will also allow development of better geodynamic models of flow coupling between the asthenospheric mantle and the subducting slab, as well as providing constraints on the physical process of melt transport through the mantle wedge.