| Studying isotope variations recorded in solar materials can help to resolve a range of problems on the origin and the evolution of the solar system. In the zoo of isotopes, titanium isotopes are important for cosmochemical studies owing to their three characteristics: refractivity, immobility, and abundance of isotopic information including both titanium mass-dependent fractionations (MDFs) and mass-independent fractionations (MIF, or isotope anomalies). Titanium MDFs provide constraints on the dynamics of solar system evolution, such as condensation and evaporation; titanium MIFs offer insights into unusual chemical processes, inheritance of nucleosynthetic anomalies or cosmogenic effects. In this dissertation, I will present the technique development for titanium isotope analysis on solar materials using multicollector inductively coupled plasma mass spectrometry (MC-ICPMS), as well as the applications of titanium isotope analysis to understand the origin and the evolution of the solar system.;MDFs in solar materials can be produced during high temperature evaporation. We investigated the isotope fractionation behavior of two highly refractory elements, calcium and titanium, during evaporation of liquid CaTiO3 in a vacuum furnace. We found that Ca and TiO2 are the dominant evaporating species and the evaporation follows Rayleigh law, but not the widely assumed exponential law. A comparison between our data and the isotopic measurements of some natural Calcium, Aluminum-rich inclusions (CAIs) suggests that, at the very early stage of solar system formation, some CAIs experienced such high temperatures that even highly refractory elements like Ti evaporated.;Ti MIF analysis was applied to investigate the origin of the Earth-Moon system. After correction for secondary cosmic-ray effects using samarium and gadolinium isotope systematics, we found that the 50Ti/ 47Ti ratio of the Moon is identical to that of the Earth within about four parts per million, which is only 1/150 of the isotopic range documented in meteorites. The isotopic homogeneity of this highly refractory element suggests that lunar material was derived from the proto-Earth mantle, an origin that could be explained by efficient impact ejection, by an exchange of material between the Earth's magma ocean and the protolunar disk, or by fission from a rapidly rotating post-impact Earth.;Titanium isotope analysis in both MDF and MIF was further applied to determine the distribution of Ti isotopes in the early solar system and to understand the nucleosynthetic origins of Ti isotopes. Titanium isotopic compositions in thirty-two CAIs from the Allende meteorite were measured. Our results provide the first evidence that nucleosynthetic anomalies are indeed in 46 Ti and 50Ti. We also found that Ti anomalies of epsilon 50Ti and epsilon46Ti in CAIs are linearly correlated and spread over a range of magnitudes. The correlation between epsilon 50Ti and epsilon46Ti extends the same correlation seen among bulk meteorites, providing constraints on the dynamic mixing of the solar disk. |
