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

CSEDI科学计划确定了HB2BO在其中发挥关键作用的两大主题。首先，CSEDI旨在了解水在地球上的循环。内心深处。其次，它旨在了解地幔深处的熔融和其他相变。近年来，为了确定HB2BO对地幔性质和过程的影响，深地界进行了大量的研究，但CSEDI科学计划提出的关键问题仍未得到解答。HB2BO在地球深部不同层间的存量仍然没有很强的约束，这些层间HB2BO的通量以及HB2BO在深部地幔中引起的熔融轨迹也还不清楚。在这里，一个理论矿物物理学家（Wentzcovitch）、一个实验岩石学家（Hirschmann）、一个实验岩石物理学家（Kohlstedt）和一个地震学家（Revenaugh）提出了一个多学科的努力，以解决一些关于HB2BO在地球上的作用的核心突出问题。地幔。研究上地幔底部低速层的厚度和结构，以及这些低速层的发生与构造环境之间的联系。这些结果将与在这些深度诱发熔融所需的HB2BO浓度的实验研究相结合，以了解这些特征对HB2BO在地幔中的储存和运输的意义。实验与从头计算相结合，将检验微量元素对OH取代、化学扩散率以及橄榄石和辉石蠕变速率的影响。利用从头算方法确定HB2BO对上地幔和过渡带弹性的影响，并将这些结果应用于寻找HB2BO的地震证据。这项拟议的研究是明尼苏达大学一项重要的跨部门多学科倡议，涉及四名教师，两名博士后研究员，两名研究生和一名本科生。这是将最先进的物质理论纳入与地幔中存在水有关的深层地球物理问题的重要一步。这项工作将通过定期小组会议来促进，以确保我们的重点仍然放在多学科方法上，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名pi来说，拟议的研究与地质与地球物理REU本科生实习地点(？地球上的流体，从表面到核心？)，赫希曼是PI， Revenaugh和Kohlstedt是常规参与者。在过去的三年里，这些pi指导了13名实习生。由Wentzcovitch领导的地球和行星材料虚拟实验室VLab，通过研讨会和教程，通过暑期实习计划培训本科生，以及将接触到这项研究的研究生和博士后的培训，深入参与到更广泛的科学界交流结果和方法。VLab吗?我们将利用美国的组织来宣传和公布这个项目的成果。

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.