Premium
The Fukang pallasite: Characterization and implications for the history of the Main‐group parent body
Author(s) -
DellaGiustina Daniella N.,
Habib Namrah,
Domanik Kenneth J.,
Hill Dolores H.,
Lauretta Dante S.,
Goreva Yulia S.,
Killgore Marvin,
Hexiong Yang,
Downs Robert T.
Publication year - 2019
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/maps.13313
Subject(s) - olivine , pyroxene , enstatite , geology , kamacite , chromite , parent body , tridymite , geochemistry , troilite , silicate , mineralogy , meteorite , augite , chemistry , plagioclase , astrobiology , cristobalite , physics , chondrite , paleontology , quartz , organic chemistry
We report the results of a study of the Fukang pallasite that includes measurements of bulk composition, mineral chemistry, mineral structure, and petrology. Fukang is a Main‐group pallasite that consists of semiangular olivine grains (Fo 86.3) embedded in an Fe‐Ni matrix with 9–10 wt% Ni and low‐Ir (45 ppb). Olivine grains sometimes occur in large clusters up to 11 cm across. The Fe‐Ni phase is primarily kamacite with accessory taenite and plessite. Minor phases include schreibersite, chromite, merrillite, troilite, and low‐Ca pyroxene. We describe a variety of silicate inclusions enclosed in olivine that contain phases rarely or not previously reported in Main‐group pallasites, including clinopyroxene (augite), tridymite, K‐rich felsic glass, and an unknown Ca‐Cr silicate. Pressure constraints determined from tridymite (<0.4 GP a), two‐pyroxene barometry (0.39 ± 0.07 GP a), and geophysical calculations that assume pallasite formation at the core–mantle boundary (CMB), provide an upper estimate on the size of the Main‐group parent body from which Fukang originated. We conclude that Fukang originated at the CMB of a large differentiated planetesimal 400–680 km in radius.