Time: 2:00-3:00PM, 26 April, 2018
Venue: Lecture Hall 221, ISESS (Building No. 16)
Abstract: The geochemists with the interests on the early solar system (ESS) and the evolution of the early Earth are alway seeking for the primitive materials to establish the history of our solar system and the Earth, to explore the mechanism of solar system formation, and to investigate the process for the Earth to grow from sterile to habitable. In this presentation, I will present my work in two aspects. In the first part, the measurement on the abundance of a significant short-lived nuclide, 60Fe, in different types of meteorites was undertaken on MC-ICP-MS, implying that 60Fe was uniformly present in a low abundance in the early Solar System. Instead of the previous hypothesis of supernova-triggered solar system formation, my work suggests that 60Fe in ESS can be only inherited from the evolution of Galaxy and all the short-lived nucllides can be contributed from Wolf-Rayet stellar wind.
In the second part of this talk, I will come down to the Earth to estimate halogens abundance in igneous zircons. In general, halogens are incompatible in zircons and highly associated with melt chemistry. Moreover, elevated halogen abundances are achieved in 50% of zircons crystallized earlier than 3.8Ga, implying the presence of Cl-rich melt on the early Earth. According to the recent revision on the abundance of halogens in chondrites and bulk silicate Earth (BSE), we propose that Cl-rich Hadean detrital zircons could reflect the transport and retention of halogens from interior Earth to the surface reservoirs, such as sea water and sediment deposition.
Speaker: Dr. Haolan Tang from the University of California, Los Angeles
