1,2Alexander A. Nemchin, 3Marc D. Norman, 4Martin J. Whitehouse, 5Evgenia Salin, 6Tao Long, 2Nicholas E. Timms, 6Xiaochao Che, 7Tao Luo
Meteoritics & Planetary Science, (in Press), 1–16
Open Source Link to Article [DOI: 10.1111/maps.70264]
1School of Earth Sciences and Engineering, Nanjing University, Nanjing, China
2Space Science and Technology Centre, School of Earth and Planetary Sciences, Curtin University, Perth, Western Australia, Australia
3Research School of Earth Sciences, The Australian National University, Canberra, Australian Capital Territory, Australia
4Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden
5Department of Geology and Mineralogy, Åbo Akademi University, Turku, Finland
6Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China
7State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, China
Published by arrangement with John Wiley & Sons
Rapidly quenched particles of melt formed as ejecta from meteoritic impacts areubiquitous in the lunar regolith. Isotopic and geochemical data for impact-produced glassyparticles from Apollo 17 regolith sample 76501 document their major and trace elementcompositions and U–Pb chronologies. Their U–Pb isotopic compositions are consistent withages ranging from a few million years to about 3.7 billion years, while their chemicalcompositions can be explained by the local targets represented in the rock and regolithcollection delivered by the Apollo 17 mission and rock fragments present in Apollo 17 coresamples. The age frequency distribution pattern obtained for 76501 impact beads definesbroad peaks at about 3.6–3.7 Ga, between about 400 and 1000 Ma, and in the last 150 Ma.These broad peaks are similar to those shown by impact bead populations from Apollo 14soil 14163 and the Chang’e 5 sample and include beads of both mare and highlandscompositions from all landing sites. In combination, these similarities support the idea thatthey reflect global impact rates or a cluster of events. Although the number of beads in anysingle sample of lunar regolith likely represents a combination of temporal changes in impactrates, destruction, burial and resurfacing during regolith evolution, the similarity of agepatterns between landing sites and across different compositions suggests a global-scalerecord of impacts rather than site-specific controls.
