Particles returned from asteroid Ryugu by the JAXA Hayabusa2 mission contain evidence of extensive aqueous alteration on its parent body and show clear mineralogical, chemical, and isotopic affinities to the rare CI (Ivuna-type) chondrite meteorites. Despite the abundant phyllosilicate and carbonate minerals that formed during aqueous processing, rare occurrences of anhydrous minerals, such as olivine and pyroxene, have also been identified. Those rare minerals provide an opportunity to understand the unaltered original material that constituted Ryugu’s protolith. In this talk, I will first briefly introduce the Hayabusa2 mission, and then present the data of in-situ isotope measurements of anhydrous silicates, carbonate minerals, and magnetite in some Ryugu particles obtained by using a large-radius ion microprobe at UCLA. How these data tell us about the history of the Ryugu asteroid, in particular (1) the origins of constituents in its protolith and (2) the sources of the fluid and the timing of chemical reactions occurring during the alteration processes, will be discussed.

Dr. Ming-Chang Liu is a cosmochemist and secondary ion mass spectrometrist currently working at the Lawrence Livermore National Laboratory. He obtained his Ph.D. in Geochemistry and Cosmochemistry from UCLA in 2008 and received postdoc training at the Carnegie Institution of Washington (2008-2010) and CRPG-CNRS in France (2010-2011). After his postdoc appointments, he became a faculty member at Academia Sinica in Taiwan and commissioned and directed his own NanoSIMS laboratory until 2014. Between 2014-2022, he was the manager of the UCLA-NSF National Ion Microprobe Facilities. His research interests primarily focus on applying secondary ion mass spectrometry techniques to address questions in cosmochemistry and astrophysics, geochronology, and biogeochemistry.

For the zoom information; please contact Rey Garduño (rgarduno@stanford.edu)