项目名称: 天然上地幔矿物热弹性参数的实验研究
项目编号: No.41274091
项目类型: 面上项目
立项/批准年度: 2013
项目学科: 天文学、地球科学
项目作者: 马麦宁
作者单位: 中国科学院大学
项目金额: 90万元
中文摘要: 高温高压下岩石、矿物热弹性参数实验研究,是探索地球深部物质组成和建立合理化地球物理模型的重要手段。本项目拟选择采自中国大陆的天然上地幔矿物,包括橄榄石、石榴石、斜方辉石和单斜辉石等为研究对象。首先利用先进的同步辐射光源和微区探测技术,在金刚石压腔和大腔体装置中进行高温高压同步辐射X 射线衍射原位测量,采用Rietveld 全谱拟合方法进行解谱,获得不同温压条件下天然矿物的晶胞参数;然后利用大腔体装置进行弹性波速度的测量,获取不同温压下样品弹性波速度的变化;最后,将宏观的弹性波速度与微观的晶胞参数相结合,由Birch-Murnaghan 状态方程获得样品的体积模量和热膨胀系数及其各向异性。对比分析天然样品与合成样品热弹性参数的异同,并以实验数据为基础,数值模拟由不同矿物组成的上地幔岩石的热弹性参数,探讨中国大陆上地幔各向异性的成因,并为大陆动力学数值模拟提供关键性物性参数。
中文关键词: 上地幔;天然矿物;高温高压;热弹性参数;各向异性
英文摘要: Experimental study on thermoelasticity parameters of rocks and minerals under high pressure and high temperature conditions plays an important role in discovering Earth's deep interior and building accurate geophysical model. In this proposal, several natural upper-mantel minerals including olivine, garnet, orthopyroxene, clinopyroxene, etc. will be collected from Chinese continent. First of all, in situ X-ray powder diffraction studies on natural samples will be carried out in diamond anvil cell or large volume press using advanced synchrotron light and micro probe techniques, and lattice parameters of minerals and their changes versus pressure and temperature will be acquired by Rietveld full spectra fitting means. Then elastic wave velocities and their changes will be measured in large volume press versus pressure and temperature. Finally, macro wave velocities and micro lattice parameters will be combined to fit the Birch-Murnaghan equation of state, yielding bulk modulus, thermal expansivity and their anisotropy, The differences of thermoelasticity parameters between natural and synthetical minerals will be found, and rock's parameters will be modeled. Experimental data could be used to explain the cause of anisotropy in upper mantle of Chinese continent and act as key parameters in numerical simulation of
英文关键词: upper mantle;natural minerals;high pressure and high temperature;thermoelasticity parameters;anisotropy