^1,2Alexander A. NEMCHIN,³Marc D. NORMAN,⁴Martin J. WHITEHOUSE,⁵Evgenia SALIN,²Nicholas E. TIMMS,⁶Tao LONG,⁶Xiaochao CHE,⁷Renaud MERLE,²Fred JOURDAN,⁸Tao LUO
Meteoritics & Planetary Science (in Press) Open Access Link to Article [https://doi.org/10.1111/maps.70103]
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, ˚Abo Akademi University, Turku, Finland
⁶Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing, China
⁷Department of Earth Sciences, Uppsala University, Uppsala, Sweden
⁸State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Wuhan, China
Published by arrangement with John Wiley & Sons

Rapidly quenched droplets of pyroclastically erupted lava are common in lunar regolith at landing sites proximal to the maria. Here, we document the U-Pb chronologies, major element, and trace element compositions of picritic glassy particles from Apollo 17 regolith sample 76501. These particles are dominated by high-Ti compositions similar to those of the established Apollo 17 orange and black pyroclastic deposits, but the textures of some beads indicate slower cooling and/or equilibration at lower temperatures. Using a new approach to calibrate SIMS U-Pb isotopic analysis of vitrophyric beads, we show that their U-Pb ages are consistent with a single or closely timed multiple eruptions ~50–100 Ma younger than the 3752 ± 9 to 3758 ± 12 Ma crystalline mare basalts collected at this site. A few picritic beads with very low-Ti compositions may be younger, but their ages are not well defined and can be ~3.3–3.6 Ga.