Orign of growth chemial 3oning in minerals

矿物在生长过程中由于化学非均质性而形成的内部结构，为研究矿物和岩石的历史以及行星的演化提供了不可缺少的信息。本文的研究目的是通过对矿物化学分带的观察，分析生长化学分带的成因，构建生长过程中化学非均质性形成的基本理论。具体方案是在统计力学的基础上构造一个新的理论，并对分区进行描述，与理论进行比较。在研究期间，我们进行了以下研究。(1)在本项目购买的扫描电镜下观察了火成岩和变质岩中矿物的化学分带。(2)给出了考虑扭结动力学和母相扩散的固溶体生长的一般方程。将该理论推广到二元体系熔体生长的情况。我们用分子动力学的方法研究了相关系。这些研究揭示了生长界面上非平衡现象的本质。对孪晶的生长进行了理论研究。(3)通过观察和新理论的构建，从生长化学分带的角度阐明了少数矿物形成过程的变化。

Internal texture in minerals due to chemical heterogeneity induced during the growth gives information which is indispensable for studying the history of minerals and rocks and the evolution of planets. The aim of the present research is to analyze the origin of growth chemical zoning based on the observation of chemical zoning in minerals and the construction of a basic theory on the formation of chemical heterogeneity during the growth. A concrete plan is toconstrict a new theory based on the statistic mechanics and to describe the zoning to compare it with the theory.We have carried out the following studies during the research period.(1) Chemical zoning in minerals in igneous and metamorphic rocks were observed under a scanning electron microscope bought in the present project.(2) A general equation for the growth of a solid solution was given by taking into considerations of both kink kinetics and diffusion in the mother phase. The theory was extended to the case of melt growth of a binary system. We study the phase relation by using the molecular dynamics. These studies reveal the essence of the non-equilibrium phenomena on the growth interfaces. A theoretical study on the growth ofa twinned crystal was also carried out.(3) The changes of the formation processes of a few minerals were clarified from the growth chemical zoning, based on the observation and the construction of the new theory.