苏长质Diogenite陨石成因研究

Howardite-eucrite-diogenite陨石是可能来自于4号小行星-灶神星的样品，其成因对于认识灶神星的演化过程与历史至关重要。其中，diogenite是主要由斜方辉石以及橄榄石组成的超基性岩石。它们的成因以及与基性的eucrite成因联系存在很多争论。新近命名的两块非角砾岩型diogenite陨石NWA 8321和NWA 8326含有较多（10-15 vol%）的长石，属于苏长质diogenite，可以为探索diogenite成因及与eucrite的成因联系提供重要线索。本项目拟基于这两块陨石开展苏长质diogenite陨石的岩相学和矿物学研究、单矿物和全岩主微量元素、含铀矿物定年以及磷灰石的H和Cl同位素研究，以探索苏长质diogenite的成因以及对diogenite与eucrite成因联系的指示意义。

The howardite-eucrite-diogenite clan meteorites are the materials that have probably derived from asteroid 4-Vesta. Their petrogenesis is a key to understanding the evolution and thermal history of Vesta. Diogenites are rocks that predominantly consist of orthopyroxene with or without olivine. Their petrogenesis and potential relationship with eucrites (which are basaltic in chemistry) remain not well constrained up to date. Two recently named diogenites NWA 8321 and NWA 8326 contain 10-15 vol% plagioclase, indicating a noritic bulk composition. They could be a bridge to understanding the genetic relationship between normal diogenites and eucrites. In this project, we plan to study the petrography and mineralogy of these two noritic diogenites, their mineral and bulk major and trace element compositions, U-Pb ages of U-bearing minerals (zircon, baddeleyite, Ca-phosphate minerals), and the hydrogen and chlorine isotope compositions in apatite. The purpose is to unravel the petrogenesis of noritic diogenites and the genetic relationship between diogenites and eucrites.