Quantitative study of textures and micro- structures of olivine- rich achondrites as indication for cumulate formation and early solid-state deformation in asteroids.

富含橄榄石的无球粒陨石的纹理和微观结构的定量研究，作为小行星累积形成和早期固态变形的指示。

• 批准号: 320205871
• 负责人: Professor Dr. Frank Erich Brenker
• 金额: --
• 依托单位: Abteilung Petrologie und Geochemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/320205871?language=en
• 关键词: Quantitative; study; textures; micro; structures

Based on our unpredicted finding of solid state plastic deformation during our work on diogenites (Tkalcec et al. 2013), which will have several far reaching consequences on the thermal history, chemical and structural equilibration in the early stages of asteroid and protoplanet formation, we propose to perform a comprehensive quantitative structural and textural study of a sub-type of unbreciated, ureilites showing a well defined crystal lattice orientation.A characterization and quantification of the micro and nano structural inventory of this rock type will be performed. This enables to unravel details of the thermal and structural evolution and the effective deformation mechanism. A combination of electron backscatter diffraction (EBSD) and large area transmission electron microscopic (TEM) will be applied in order to measure details of the crystallographic preferred orientation and relate them to texture forming processes like crystallization, compaction, shock effects and deformation mechanism. These processes are essential for the understanding of planetary differentiation, mantle mingling or mixing and initial cooling of asteroids and planetary embryos.Ureilites are ideal candidates for this attempt as they represent the second most common type of achondrites, resemble olivine-rich mantle rocks and the fast cooling from their initial conditions preserve most of the original fabric and microstructure.

基于我们在对闪长岩的研究中意外发现的固态塑性变形（Tkalcec 等人，2013），这将对小行星和原行星形成早期阶段的热历史、化学和结构平衡产生一些深远的影响，我们建议对显示出明确晶格方向的未砾化尿素岩亚型进行全面的定量结构和织构研究。将执行这种岩石类型。这使得能够揭示热和结构演化的细节以及有效的变形机制。将应用电子背散射衍射 (EBSD) 和大面积透射电子显微镜 (TEM) 的组合来测量晶体择优取向的细节，并将其与结晶、压实、冲击效应和变形机制等织构形成过程联系起来。这些过程对于了解行星分化、地幔混合或混合以及小行星和行星胚胎的初始冷却至关重要。Ureilites 是这次尝试的理想候选者，因为它们代表了第二种最常见的无球粒陨石类型，类似于富含橄榄石的地幔岩石和从初始条件快速冷却保留了大部分原始织物和微观结构。