Pressure and water influences on alternating active slip systems of single crystal olivine at the upper mantle pressures

上地幔压力下压力和水对单晶橄榄石交替活动滑移系统的影响

• 批准号: 1015509
• 负责人: Jiuhua Chen
• 金额: $ 28.82万
• 依托单位: Florida International University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-15 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1015509&HistoricalAwards=false
• 关键词: Pressure; water; influences; alternating; active

This project focuses on study of mechanical properties of olivine, a dominant mineral in Earth's upper mantle. The objectives of this project include studies of the flow properties of individual slip system under different pressures and water containing environments. Success of the project will help to explain formation/variation of lattice preferred orientation (LPO) of this major constitution (olivine) of the upper mantle under the conditions of Earth's interior. As the LPO is believed to give rise to seismic anisotropy, this study will supply experimental evidence, from the mineral physics point of view, to understand the attenuation of seismic anisotropy observed at about 200km depth in the upper mantle, the cause of this attenuation has been one of the long standing issues for Earth science community. The project will take advantage of state-of-the-art technical developments in high-pressure deformation experiments at synchrotron facilities of national laboratories. The deformation-DIA (D-DIA) apparatus in conjunction with a synchrotron x-ray source will be the major instrument for the experimental investigation. This apparatus has extended the pressure range for studying aggregate samples beyond 10 GPa. To study properties of individual slip systems, this project will use single crystals as the deformation specimens in a modified cell assembly. Flow properties of a-slip system, (010)[100], and c-slip system, (010)[001] will be studied individually and comparatively. In the comparative study, two samples oriented in such directions that active (010)[100] and (010)[001] slip, respectively, will be deformed simultaneously in sequence during the experiment. This will minimize the experimental error when determination of which of these two slip systems is activated at given pressure/temperature/chemical conditions. Samples recovered after deformation experiments will be examined using FTIR and TEM to determine the water concentration and microstructure of the sample. The project will enhance the experimental capability of the high pressure facility at the X17B2 beamline of the National Synchrotron Light Source. This facility serves a large number of general users from Earth science community. The project will promote collaborations with experts/pioneers in the traditional deformation field to valid the new technology. In addition, students from underrepresented groups (women/Hispanics) will be attracted, engaged, trained during the project.

该项目的重点是研究橄榄石的机械特性，橄榄石是地球上地幔的主要矿物。该项目的目标包括研究不同压力和含水环境下单个滑移系统的流动特性。该项目的成功将有助于解释地球内部条件下上地幔这一主要成分（橄榄石）的晶格择优取向（LPO）的形成/变化。由于LPO被认为会引起地震各向异性，本研究将从矿物物理学的角度提供实验证据，以了解上地幔约200公里深度处观测到的地震各向异性的衰减，这种衰减的原因一直是地球科学界长期存在的问题之一。该项目将利用国家实验室同步加速器设施高压变形实验的最先进技术发展。变形 DIA (D-DIA) 装置与同步加速器 X 射线源结合将成为实验研究的主要仪器。该设备将研究骨料样品的压力范围扩展至 10 GPa 以上。为了研究单个滑移系统的特性，该项目将使用单晶作为改进的单元组件中的变形样本。 a-滑移系统(010)[100]和c-滑移系统(010)[001]的流动特性将分别进行比较研究。在比较研究中，两个样品分别沿主动（010）[100]和（010）[001]滑移方向定向，在实验过程中将同时依次变形。当确定在给定压力/温度/化学条件下激活这两个滑移系统中的哪一个时，这将使实验误差最小化。变形实验后回收的样品将使用 FTIR 和 TEM 进行检查，以确定样品的水浓度和微观结构。该项目将增强国家同步光源X17B2光束线高压装置的实验能力。该设施为地球科学界的大量普通用户提供服务。该项目将促进与传统变形领域专家/先驱的合作，以验证新技术。此外，项目期间将吸引、参与和培训来自代表性不足群体（女性/西班牙裔）的学生。