Meteoritics & Planetary Science 55, Nr 10, 2184–2205 (2020) doi: 10.1111/maps.13575 Mineralogical and oxygen isotopic study of a new ultrarefractory inclusion in the Northwest Africa 3118 CV3 chondrite Yong XIONG1, Ai-Cheng ZHANG *1,2, Noriyuki KAWASAKI3, Chi MA 4, Naoya SAKAMOTO5, Jia-Ni CHEN1, Li-Xin GU6, and Hisayoshi YURIMOTO3,5 1State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China 2CAS Center for Excellence in Comparative Planetology,Hefei, China 3Department of Natural History Sciences, Hokkaido University, Sapporo 060-0810, Japan 4Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA 5Isotope Imaging Laboratory, Creative Research Institution Sousei, Hokkaido University, Sapporo 001-0021, Japan 6Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China *Corresponding author. E-mail:
[email protected] (Received 27 March 2020; revision accepted 09 September 2020) Abstract–Calcium-aluminum-rich inclusions (CAIs) are the first solid materials formed in the solar nebula. Among them, ultrarefractory inclusions are very rare. In this study, we report on the mineralogical features and oxygen isotopic compositions of minerals in a new ultrarefractory inclusion CAI 007 from the CV3 chondrite Northwest Africa (NWA) 3118. The CAI 007 inclusion is porous and has a layered (core–mantle–rim) texture. The core is dominant in area and mainly consists of Y-rich perovskite and Zr-rich davisite, with minor refractory metal nuggets, Zr,Sc-rich oxide minerals (calzirtite and tazheranite), and Fe-rich spinel. The calzirtite and tazheranite are closely intergrown, probably derived from a precursor phase due to thermal metamorphism on the parent body.