Lunar surface exposure models for meteorites Elephant Moraine 96008 and Dar al Gani 262 from the Moon

We derived the cosmic-ray and solar particle exposure history for the two l unar meteorites Elephant Moraine (EET) 96008 and Dar al Gani (DaG) 262 on t he basis of the noble gas isotopic abundances including the radionuclide Kr -81. For EET 96008, we propose a model for the exposure to cosmic rays and solar particles in three stages on the Moon: an early stage similar to 500 Ma ago, lasting less than 9 Ma at a shallow shielding depth of less than or equal to 20 g/cm(2), followed by a stage when the material was buried, wit hout exposure, until it was exposed in a recent stage. This recent stage, a t a shielding depth in a range of 200-600 g/cm(2), lasted for similar to 26 Ma until ejection. This model is essentially the same as that previously f ound for lunar meteorite EET 87521; thus, pairing of the two Elephant Morai ne lunar meteorites that were recovered on the same icefield in Antarctica is confirmed by our data. The cosmic-ray-produced isotopes, the trapped sol ar and lunar atmospheric noble gases, as well as the radionuclide Kr-81 obs erved for the DaG 262 lunar meteorite are consistent with a one-stage lunar exposure history. The average burial depth of the Dar al Gani material bef ore ejection was within a range of 50-80 g/cm(2). The exposure to cosmic ra ys at this depth lasted 500-1000 Ma. This long residence time for Dar al Ga ni at relatively shallow depth explains the high concentrations of implante d solar noble gases.