Abstract
We measured the hydrogen isotopic composition (D/H ratios) and U-Pb chronology of phosphate minerals in a young Martian meteorite: LAR 06319. D/H ratios of melt-inclusions in the meteorite were also investigated to evaluate the presence of water reservoirs on Mars in recent times. The total Pb/U dating of multiple grains of apatite and merrillite yield a concordant date of 167 ± 57 Ma, interpreted as the crystallization age, suggesting that both apatite and merrillite in this meteorite have preserved their igneous histories. The D/H ratios of an apatite grain show good reproducibility yielding a dD value of 4250 ± 120‰, whereas those of merrillite show larger D/H variations with the maximum δD value of 5260 ± 790‰. However, mafic glass in melt-inclusions shows extremely large variation in δD, ranging from ca. 1070‰ to 6830 ± 460‰. The different D/H signatures recorded in these phases reflect the contributions of different hydrous components with distinct D/H ratios, possibly incorporated at different times. It is inferred that several isotopically distinct water reservoirs exist in the present Martian surface/sub-surface system.
| Original language | English |
|---|---|
| Pages (from-to) | 363-377 |
| Number of pages | 15 |
| Journal | Geochemical Journal |
| Volume | 50 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - 2016 |
| Externally published | Yes |
Keywords
- D/H ratio
- Martian meteorites
- NanoSIMS
- Phosphate
- U-Pb dating
ASJC Scopus subject areas
- Geophysics
- Geochemistry and Petrology