Chemical constraints from early Solar System materials

2 Chemical constraints from early Solar System materials 

Several types of the early Solar System materials are available for laboratory analysis (see Chapter 1 and Table 1.1 and Fig. 1.1). Each material has unique characteristics and provides specific constraints on the chemistry of the solar nebula. Major components of this sample are meteorites, fragments of asteroids, that serve as an excellent archive of the early Solar System conditions. Primitive chondritic meteorites contain glassy spherical inclusions termed chondrules, some of the oldest solids in the Solar System. Most chondrites were modified by aqueous alteration or metamorphic processes in parent bodies but there are some chondrites that are minimally altered (un-equilibrated chondrites, UCs). They have yielded a wealth of information on the chemistry, physics, and evolution of the young Solar System. 

Calcium-aluminum-rich refractory inclusions (CAIs) in chondrites are the oldest Solar System solids (2-3 Myr older than chondrules, see Chapters 1 and 9). The mineralogy, petrographic, chemical, and isotopic characteristics of these primitive solids constrain the physical and chemical processes through which these materials have been processed (Zhu et al. 2001 Becker Walker 2003 Biz-zarro et al. 2004 Chaussidon et al. 2008). The primordial presolar grains were 

---