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Dynamics of phase transition and crystal growth of earth interior

地球内部相变和晶体生长动力学

基本信息

批准号：
07304073
负责人：
YAMANAKA Takamitsu
金额：
$ 2.69万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Conventional thermodynamical phase studies of earth interiors are not enough scientific approaches to comprehend the various geophysical phenomena Dynamical investigations of mantle substances are also significant to understand mantle dynamics such as subjection of slab and tectonic movement. It has been known that earth interiors have many types of structure changes under high pressure and temperature. Many attentions have been paid to the following phase changes ; (1).phase transformation (transition, melt, amorphization) ; (2).decomposition, (exsolution, dissociation, phase separation) ; (3).crystallization, (nucleation, growth, domain growth) ; (4).chemical reaction (solid-solid, solid-molten salt) ; (5).electronic changes, (excitation of electronic, ionic and radical). These transformations tend to maintain their stability in the new circumference and induced by changing the physical and chemical conditions such as pressure, temperature, partial pressure of oxygen, stress field, chemical potential around the substances in the mantle or shell.In order to elucidate these phase changes, in situ X-ray diffraction studies have been made using diamond anvil (DAC) or multianvil high pressure apparatusinstalled in synchrotron radiation at Photon Factory in National Institute for High Energy Physics. Structure analyzes and physical properties under high pressure and temperature similar to the mantle condition or subjection zone were also investigated.Compressibility, elastic constant and thermal expansion coefficients of many mantle minerals have been measured. Electric conductivity has also been measure as a function of pressure.Molecular dynamical calculation simulates the structure and physical properties. Pressure-induced transformation, melting or crystallization from molten salt have been simulated under extreme conditions.

传统的地球内部热力学相研究不足以科学地理解各种地球物理现象。地幔物质的动力学研究对于理解地幔动力学（如板块和构造运动的隶属）也很重要。众所周知，在高压和高温下，地球内部会发生多种类型的结构变化。以下的相变引起了很多关注：(1).相变（相变、熔融、非晶化）；(2)分解（溶出、解离、相分离）；(3)结晶（成核、生长、畴生长）；(4).化学反应（固-固、固-熔盐）；(5).电子变化（电子、离子和自由基的激发）。这些转变倾向于在新的周长中保持其稳定性，并通过改变地幔或壳层物质周围的物理和化学条件（如压力、温度、氧分压、应力场、化学势）而引起。为了阐明这些相变，利用安装在国家高能物理研究所光子工厂同步辐射中的金刚石砧（DAC）或多砧高压装置进行了原位x射线衍射研究。在类似地幔或隶属带的高压和高温条件下进行了构造分析和物性研究。测定了许多地幔矿物的压缩系数、弹性常数和热膨胀系数。电导率也被测量为压力的函数。分子动力学计算模拟了分子的结构和物理性质。在极端条件下模拟了熔融盐的压力诱导转变、熔化或结晶。