U‐Pb geochronology of zircons from lunar breccia 73217 using a sensitive high mass‐resolution ion microprobe

U‐Pb ages of four zircons in thin‐sections of lunar breccia 73217 have been determined using the sensitive high‐resolution ion microprobe, SHRIMP. All crystals show remarkably little loss of radiogenic Pb and give U‐Pb ages that are within 10% of concordance at 4356 −14 +23 m.y. Two of the crystals ... View More