Formation processes of achondrite parent bodies as inferred from meteorites.

非球粒陨石是在原始原行星上发育的分异陨石，是太阳系早期全部或部分熔融的原始物质结晶形成的。我们试图在其组成物质的矿物学和化学的基础上重建它们的原行星，并推断它们的形成条件。应用计算机图像处理技术(CMA法)，将扫描电子显微镜获得的元素分布图转化为RGB彩色图像。这些图像被存储在MD光盘上，作为非球粒陨石的图像数据库。一组具有非球粒陨石结构但具有球粒陨石原始物质特征的陨石与主带小行星中最丰富的S类小行星有关。这些陨石可能是由于小行星碰撞引起的富Al-Ca部分熔体的部分剥离和Fe-Ni-S共晶熔体的迁移以及晶体的生长而形成的。我们研究的两个新的南极陨石属于这一类，填补了原始无球粒陨石和罗丹石之间的空白，是同类中的石质铁陨石。角砾状玄武岩陨石被称为单粒榴辉石，具有快速生长的结构，但其镁铁在辉石中的分布具有均匀的化学成分。CMA方法的应用表明，它们是在原行星上热退火的产物。根据辉石的均一程度，根据与母体上的陨坑事件有关的热变质作用，所有这些榴辉石都被划分为1-6类。用CMA方法研究了两块新的月球陨石，结果表明它们是厚玛来玄武岩中的角砾岩。它们包括在阿波罗样品中没有太好代表的低钛玄武岩。还鉴定了早期结晶的富含镁的母马成分。

Achondrites are differentiated meteorites developed on primitive protoplanets, which have been formed by crystallization of totally or partially molten primitive source materials in the early solar system. We have tried to reconstruct their protoplanets on the basis of mineralogy and chemistry of their component materials and deduced their formation conditions. A method of computer image processing techniques (CMA method) has been applied to utilize elemental distribution maps obtained by SEM in terms of RGB color images. The image are stored on MD discs to be used as image database of achondrites.A group of meteorites with achondritic textures, but with signatures of chondritic primitive materials have been related to S-type asteroids most abundant in the main belt asteroids. These meteorites can be formed by partial removal of Al-Ca-rich partial melts and relocation of Fe-Ni-S eutectic melts and crystal growth induced by planetesimal-scale collisions. Two new Antarctic meteorites we studied belong to this group and fill gaps between primitive achondrites and lodranites, stony iron meteorites of one of its kind.Brecciated basalt-like meteorites known as monomict eucrites show quickly grown textures but with homogeneous chemistry of their Mg-Fe distribution in pyroxenes. Application of the CMA method shows that they are products of thermal annealing on a protoplanet. All these eucrites have been classified into type 1 to 6 on the basis of degrees of homogenization of their pyroxenes by the thermal metamorphism related to the cratering events on the parent body.Two new lunar meteorites have been investigated by the CMA method and are turned out to be breccias of thick mare basalts. They include low Ti basalts not too well represented in the Apollo samples. Early crystallized Mg-rich mare components were also identified.