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Miller Range (MIL) 05035 and LaPaz Icefield (LAP) 02224 are unbrecciated lunar basalt meteorites. In this report, we studied their petrography and mineralogy and made in situ uranogenic Pb/Pb dating of Zr-rich minerals. Petrography and mineralogy of these two lunar meteorites are consistent with previous investigations. The zirconolite Pb/Pb age of MIL 05035 is 3851±8 Ma (2σ), in excellent agreement with previous reports. This age suggests that MIL 05035 could be paired with Asuka 881757, a low-Ti mare basalt meteorite. The magmatic event related to MIL 05035 was probably due to the late heavy impact bom- bardment on the moon around 3.9 Ga. One baddeleyite grain in LAP 02224 shows a large variation of Pb/Pb age, from 3109±29 to 3547±21 Ma (2σ), much older than the whole-rock age of the same meteorite (~3.02±0.03 Ga). The other baddeleyite grain in LAP 02224 has an age of 3005±17 Ma (2σ). The result indicates that the minimum crystallization age of LAP 02224 is ~3.55 Ga and the younger ages could reflect late thermal disturbance on U-Pb system.
Miller Range (MIL) 05035 and LaPaz Icefield (LAP) 02224 are unbreccated lunar basalt meteorites. In this report, we studied their petrography and mineralogy and made in situ uranogenic Pb / Pb dating of Zr-rich minerals. Petrography and mineralogy of these two This zirconia Pb / Pb age of MIL 05035 is 3851 ± 8 Ma (2σ), in excellent agreement with previous reports. This age suggests that MIL 05035 could be paired with Asuka 881757, a low-Ti mare basalt meteorite. The magmatic event related to MIL 05035 was probably due to the late heavy impact bom- bardment on the moon around 3.9 Ga. One bad deleyite grain in LAP 02224 shows a large variation of Pb / Pb age from 3109 ± 29 to 3547 ± 21 Ma (2σ), much older than the whole-rock age of the same meteorite (~ 3.02 ± 0.03 Ga). The other baddeleyite grain in LAP 02224 has an age of 3005 ± 17 Ma (2σ). The result indicates that the minimum crystallization age of LAP 02224 is ~ 3.55 Ga and the younger ages could reflect late thermal disturbance on U-Pb systems.