Abstract
Water is the one of most precious resources for planetary utilisation. Lunar nearside impact glass beads (IGBs) have been demonstrated to contain abundant solar wind-derived water (SW-H(2)O); however, little is known about its farside counterpart. Here, we report the water abundances and hydrogen isotope compositions and their distribution in farside IGBs collected by the Chang'e-6 mission to investigate the role of IGBs in the lunar surface water cycle. Farside IGBs are found to have water abundances of ~10-1,070 μg.g(-1) with hydrogen isotopes (δD) ranging from -988‰ to >2000‰ and display typical SW-H(2)O hydration profiles. The SW-H(2)O hydration depths in farside IGBs are strikingly shallower than in nearside IGBs. Moreover, the hydration profiles are only found in mare IGBs, with none observed in non-mare IGBs, indicating that SW-H(2)O hydration in IGBs is likely composition dependent. These findings indicate that SW-H(2)O storage of IGBs exhibits a dichotomy distribution in lunar soils.