HED陨石高强度冲击变质的矿物学及年代学制约

灶神星是太阳系小行星带中最大天体之一，其形成之后的撞击历史对认识小行星带和太阳系的撞击历史有代表性。因此，弄清其高强度冲击变质的特征和历史不仅对了解灶神星本身的演化有重要科学意义，对构建小行星带和太阳系动力学演化模型也非常重要。. 本项目将在大量灶神星陨石（HED陨石）中搜寻高强度冲击变质的矿物学记录，使用微区原位成分和结构分析技术对其进行表征，与前人静态高压实验结果进行比较以限定灶神星陨石冲击变质发生的压力、温度和高压持续时间等条件。项目还将通过对高强度冲击变质灶神星陨石中锆石、斜锆石和磷灰石等矿物进行矿物学和U-Pb年代学研究，揭示天然冲击变质事件对这些矿物结构和年龄的影响与灶神星的高强度冲击变质历史。

Asteroid 4 Vesta is one of the largest asteroids in the main belt of the solar system. Its impact history after formation and differentiation might reflect the impact history of the main asteroid belt and even the whole solar system. Therefore, unraveling intense shock-induced features and thermal history of Vesta is not only critical to constrain the evolution of asteroid 4 Vesta itself, but also important to establish a model of dynamic evolution of the main asteroid belt and the solar system. .This proposal will search for possible mineralogical records of intense shock metamorphism in Howardite-Eucrite-Diogenite (HED) meteorites. The chemical and structural features of minerals related to shock metamorphism will be characterized by in situ microscopic techniques and compared with results from static high-pressure experiments to constrain the P-T-t conditions of shock metamorphism in HED meteorites. We will also study zircon, baddeleyite, and apatite in shocked HED meteorites to constrain the potential effects of natural shock metamorphism on crystal structure and U-Pb geochronology of these minerals and to reveal thermal history related to intense shock metamorphism in HED meteorites and asteroid 4 Vesta.