Rb‐Sr age of a Luna 16 basalt and the model age of lunar soils
- Creators
- Papanastassiou, D. A.
-
Wasserburg, G. J.
Abstract
A Rb-Sr internal isochron on a 62 mg basaltic boulder from the Luna 16 mission yields an age of 3.42 ± 0.18 AE and a low initial ⁸⁷Sr/⁸⁶Sr 0.69906 ∓ 4 (1σ errors). The total range in measured ⁸⁷Sr/⁸⁶Sr for mineral separates of this sample was 1.3 per mil. The ages of basalts from four mare sites determine a narrow time interval of 0.55 AE for the flooding of the maria. Initial ⁸⁷Sr/⁸⁶Sr for these basalts are restricted to extremely low values, indicating that they all originated in low Rb/Sr regions. Luna 16 soils have low Rb/Sr (≈ 0.007) and yield model ages T_(BABI) = 4.2 ± 0.3AE and T_(BABI) = 4.1 ± 0.3AE. Lunar soils from Apollo 11, 12, 14, 15 and Luna 16 all lie very close to a 4.6 AE isochron which passes through BABI. This appears to be a universal characteristic of lunar soils and must correspond to lunar differentiation processes closely following the time of formation of the moon.
Additional Information
We thank the Soviet Academy of Sciences and The National Aeronautics and Space Administration for arranging for the exchange of lunar samples. The age determination on B-1 was critically dependent on the meticulous and mass conserving mineral separations of J. Brown. We greatly appreciate the confidence which the Lunar Sample Analysis Planning Team and the Curator of lunar samples have shown by entrusting us with the handling of such an extremely valuable sample. This work was supported by NASA under NAS-9-8074.Additional details
- Eprint ID
- 117931
- Resolver ID
- CaltechAUTHORS:20221121-967794900.5
- NAS-9-8074
- NASA
- Created
-
2022-11-28Created from EPrint's datestamp field
- Updated
-
2022-11-28Created from EPrint's last_modified field
- Other Numbering System Name
- Caltech Division of Geological and Planetary Sciences
- Other Numbering System Identifier
- 2100