Premium
Regolith history of lunar meteorites
Author(s) -
Lorenzetti S.,
Busemann H.,
Eugster O.
Publication year - 2005
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/j.1945-5100.2005.tb00383.x
Subject(s) - regolith , meteorite , neon , astrobiology , isotopes of neon , geology , mineralogy , materials science , physics , atomic physics , argon
— The regolith evolution of the lunar meteorites Dhofar (Dho) 081, Northwest Africa (NWA) 032, NWA 482, NWA 773, Sayh al Uhaymir (SaU) 169, and Yamato (Y‐) 981031 was investigated by measuring the light noble gases He, Ne, and Ar. The presence of trapped solar neon in Dho 081, NWA 773, and Y‐981031 indicates an exposure at the lunar surface. A neon three‐isotope diagram for lunar meteorites yields an average solar 20 Ne/ 22 Ne ratio of 12.48 ± 0.07 representing a mixture of solar energetic particles neon at a ratio of 11.2 and solar wind neon at a ratio of 13.8. Based on the production rate ratio of 21 Ne and 38 Ar, the shielding depth in the lunar regolith of NWA 032, NWA 482, SaU 169, and Y‐981031 was obtained. The shielding depth of these samples was between 10.5 g/cm 2 and >500 g/cm 2 . Based on spallogenic Kr and Xe, the shielding depth of Dho 081 was estimated to be most likely between 120 and 180 g/cm 2 . Assuming a mean density of the lunar regolith of 1.8 g/cm 3 , 10.5 g/cm 2 corresponds to a depth of 5.8 cm and 500 g/cm 2 to 280 cm below the lunar surface. The range of regolith residence time observed in this study is 100 Ma up to 2070 Ma.