Lunar meteorites represent a more random sampling of Lunar material than th
e Apollo or Luna collections and, as such, Lunar meteorite impact melt ages
are the most important data in nearly 30 years with which to reexamine the
Lunar cataclysm hypothesis. Within the lunar meteorite breccias MAC 88105,
QUE 93069, DaG 262, and DaG 400, seven to nine different impact events are
represented with Ar-40-Ar-39 ages between 2.76 and 3.92 billion years ago
(Ca). The Lack of impact melt older than 3.92 Ca supports the concept of a
short, intense period of bombardment in the Earth-moon system at similar to
3.9 Ca. This was an anomalous spike of impact activity on the otherwise dec
lining impact-frequency curve.