Study on the initial states of the solar system by measuring microdistribution of noble gases in meteorites

为了确定影响早期太阳系物质演化的物理化学过程和条件，用激光微探针技术测量了太阳系中稀有气体的微区分布，并与陨石结构进行了比较。碳质玄武岩中捕获的气体主要存在于球粒边缘。在粉碎部分发现了太阳气体，但在原生增生岩石中没有发现，这表明太阳星云的物质密度很高，太阳风没有到达球粒边缘的形成区域。通过对阿连德进行30 ~ 70 GPa的冲击，测定了它的气体损失，在70 GPa的冲击下，部分岩石熔化，70%的Q-气体损失，而被困在前太阳金刚石中的HL-气体却没有损失。还研究了层状硅酸盐矿物脱水后的气体损失，以寻找早期太阳星云的物理化学条件。本文分析了IDP、南极微陨石和深海磁性球粒等宇宙尘的稀有气体、微量元素和矿物组成。利用同步辐射高亮度光源对IDP陨石和微陨石的矿物成分以及磁性球粒的微量元素丰度进行了测定。

In order to determine physico-chemical process and condition to affect the evolution of materials in the early solar system, noble-gas microdistribution was measured by a laser microprobe technique and was compared to the meteorite texture. Trapped gases in carbonaceous chondrites reside mainly in chondrule rims. Solar gas was found in comminuted parts but not in primary accreted rocks, indicating that the material density of the solar nebula was so high that the solar wind did not reach the formation region of chondrule rims. Gas-loss from Allende was determined by artificially applying impact-shocks of 30 to 70 GPa to it. At 70 GPa shock, part of rock melted and 70% of Q-Gas was lost, whereas HL-gas that was trapped in presolar diamond was retained without loss. Gas-loss-following dehydration of phyllosilicate minerals was studied as well to find physico-chemical conditions in the early solar nebula. Gas concentration in dehydrated carbonaceous chondrites is constrained by heating temperature and time as well as graphitization of organic carbon.Cosmic dusts including IDP, Antarctic micrometeorites and magnetic deep-sea spherules were analyzed for noble-gas, trace element and mineral composition. Determinations of mineral compositions of IDP and micrometeorites and trace element abundance for magnetic spherules were carried out using high luminosity of synchrotron radiation.