CSEDI: Integrated Study of Water (H2O) in the Mantle: Processes and Signature

CSEDI科学计划确定了HB2BO发挥关键作用的两大主题。首先，CSEDI的目标是了解地球上的水循环？s深的内部。其次，它旨在了解深部地幔的熔融和其他相变。近年来，地球深部社区集中了巨大的努力，以确定HB2BO对地幔性质和过程的影响，然而，CSEDI科学计划提出的关键问题仍然没有答案。对于HB2BO在地球深部不同层中的含量，仍然没有强有力的限制，也不知道这些层之间的HB2BO通量或由HB2BO在深部地幔中引起的熔融的位置。在这里，提出了一个多学科的努力之间的理论矿物物理学家（Wentzcovitch），实验岩石学家（Hirschmann），实验岩石物理学家（Kohlstedt），和地震学家（Revenaugh），以解决一些核心的悬而未决的问题有关的作用HB2BO在地球上？的斗篷。将从地震学的角度寻找关于上地幔底部低速层的厚度和结构的证据，以及这些层的出现与构造环境之间的联系。这些结果将结合实验研究的浓度HB2BO必要的诱导熔化在这些深度，了解这些功能的意义HB2BO存储和运输在地幔。实验和从头计算相结合，将研究的影响，对OH取代，对化学扩散，橄榄石和辉石蠕变速率的微量元素。将使用从头算计算来确定HB 2BO对上地幔和过渡带弹性的影响，并将这些结果应用于寻找HB 2BO的地震学证据。拟议的研究代表了明尼苏达大学的一个重要的跨部门多学科倡议，涉及四名教师，两名博士后研究人员，两名研究生和一名本科生。这是将最先进的材料理论结合到与地幔中水的存在有关的深层地球物理问题中的重要一步。将通过定期举行小组会议来促进这一努力，以确保我们的重点仍然是多学科方法，并促进所有参与者的跨学科学习。对于地质与地球物理系的三个PI，拟议的研究与地质与地球物理REU本科实习地点（？地球上的水，从地表到地核？）赫希曼是主要研究者，雷文诺和科尔施泰特是定期参与者。在过去的三年里，这些PI已经监督了十三名实习生。由Wentzcovitch指导的地球和行星材料虚拟实验室，VLab深入参与了通过研讨会和教程向更广泛的科学界传达结果和方法，通过暑期实习计划培训本科生，以及研究生和博士后的培训也将接触到这项研究。虚拟实验室？的组织将被用来促进和透露这个项目的成果。

The CSEDI Science Plan identifies two broad themes in which HB2BO plays a critical role. First, CSEDI aims to understand cycling of water through the Earth?s deep interior. Second, it aims to understand melting and other phase transitions in the deep mantle. In recent years, the deep Earth community has concentrated a tremendous effort in order to determine the influence of HB2BO on mantle properties and processes, yet, key questions raised by the CSEDI Science Plan remain unanswered. There are still no strong constraints on the inventory of HB2BO in different layers of the deep Earth, nor are the fluxes of HB2BO between these layers or the locus of melting induced by HB2BO in the deep mantle known. Here a multidisciplinary effort is proposed between a theoretical mineral physicist (Wentzcovitch), an experimental petrologist (Hirschmann), an experimental rock physicist (Kohlstedt), and a seismologist (Revenaugh) to address some of the central outstanding issues regarding the role of HB2BO in the Earth?s mantle. Evidence regarding the thickness and structure of low velocity layers at the bottom of the upper mantle, as well as for links between the occurrence of such layers and tectonic environment will be searched for seismically. These results will be combined with experimental studies of the concentrations of HB2BO necessary to induce melting at these depths to understand the significance of these features for HB2BO storage and transport in the mantle. Experiments and ab initio calculations will be combined to examine the influence of minor element on OH substitution, on chemical diffusivity, and on creep rates of olivine and pyroxenes. Ab initio calculations will be use to determine the influence of HB2BO on the elasticity of the upper mantle and transition zone, and those results will be applied to search for seismological evidence of HB2BO. The proposed research represents a significant inter-departmental multi-disciplinary initiative at the University of Minnesota involving four faculty, two post-doctoral researchers, two graduate students, and one undergraduate. It is a major step in incorporating state-of-the-art materials theory to deeply seated geophysical problems related to the presence of water in the mantle. This effort will be facilitated by regular group meetings to ensure that our focus remains on multidisciplinary approaches and to promote interdisciplinary learning of all of the participants. For the three PIs in the Department of Geology and Geophysics, the proposed research dovetails well with the Geology and Geophysics REU undergraduate intern site (?Fluids in the Earth, from the Surface to the Core?) for which Hirschmann is the PI and Revenaugh and Kohlstedt are regular participants. In the past three years, these PIs have supervised thirteen interns. The Virtual Laboratory for Earth and Planetary Materials, VLab, directed by Wentzcovitch is deeply involved in communicating results and methods to the broader scientific community through workshops and tutorials, in the training of undergraduates through the summer internship program, and in the training of graduate students and post-docs which will also be exposed to this research. VLab?s organization will be used to promote and divulge outcomes of this project.