Earth Planets Space, Vol. 57 (No. 9), pp. e13-e16, 2005E-LETTER
Naoji Sugiura1, Akiko Miyazaki1, and Keizo Yanai2
1Department of Earth and Planetary Science, University of Tokyo, Japan
2Department of Civil and Environmental Engineering, Iwate University, Japan
(Received May 18, 2005; Revised July 26, 2005; Accepted July 27, 2005)
Mn-Cr chronology of four quenched angrites showed that they formed nearly at the same time (4562 Ma) on the surface of the parent-body. Based on the chemical compositions, the cosmic ray exposure ages, and
considerations on the thermal history of an achondrite parent-body, we suggest that the four angrites formed on top of a shallow magma ocean on the angrite parent body.
Key words: Age, angrites, Mn-Cr dating, SIMS.