Calcium and titanium isotope fractionation in refractory inclusions: Tracers of condensation and inheritance in the early solar protoplanetary disk

J.I. Simon, M.K. Jordan, M.J. Tappa, E.A. Schauble, I.E. Kohl, E.D. Young
2017 Earth and Planetary Science Letters  
Keywords: condensation Ca-, Al-rich inclusions Ca and Ti isotope fractionation solar nebula protoplanetary disk 50 Ti isotopic anomalies Measured and modeled Ca and Ti isotopic fractionation effects in a diverse suite of refractory inclusions are used to understand processes of condensation in the solar protoplanetary disk where they and their precursor materials formed. This coordinated approach reveals largely decoupled isotopic signatures and implies that few, if any, of the studied
more » ... s can be considered primary condensates. All studied inclusions are enriched in light Ca isotopes (∼−0.2 to −2.8h/amu), but only two show correspondingly light Ti isotopes. Studied inclusions exhibit both heavy and light Ti isotope enrichments (∼0.3 to −0.4h/amu). These refractory element isotopic signatures, therefore, suggest admixture and reprocessing of earlier formed materials with distinct condensation histories. Along with coordinated measurements of 50 Ti isotopic anomalies, which span a range from ∼0 to ∼40 epsilon-unit excesses, the comparison of measured and modeled fractionation of Ca and Ti isotopes provides a powerful approach to understanding primitive nebular processes and environments in the protoplanetary disk. Remarkable evidence for Ca isotopic zoning within a typical Type B1 inclusion exemplifies the potential record of the earliest solar nebula that is likely lost and/or overprinted in the isotopic compositions of more volatile elements (e.g., Mg, Si, and O) by later modification processes. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
doi:10.1016/j.epsl.2017.05.002 fatcat:zauvs7y4ifbgpktjj3vjpnxom4