Code and data used for reproducing calculations of lunar crustal thermal evolution and zircon resetting during a tidal heating event

The last giant impact on Earth is thought to have formed the Moon. The
timing of this event can be determined by dating the different rocks
assumed to have crystallized from the lunar magma ocean (LMO). This has
led to a wide range of estimates for the age of the Moon between 4.35 and
4.51 billion years ago (Gyr), depending on whether ages for lunar
whole-rock samples or individual zircon grains are used. Here we argue
that the common occurrence of ~4.35 Gyr ages among lunar rocks and a spike
in zircon ages at about the same time is indicative of a remelting event
driven by the Moon’s orbital evolution rather than the original
crystallization of the LMO. We show that during passage through the
Laplace Plane Transition the Moon experienced sufficient tidal heating and
melting to reset the formation ages of most lunar samples, while retaining
an earlier frozen-in shape and rare, earlier-formed zircons. This new
paradigm reconciles existing discrepancies in estimates for the
crystallization time of the LMO, and permits formation of the Moon within
a few tens of Myr of solar system formation, consistent with dynamical
models of terrestrial planet formation11.  Remelting of the Moon
also explains the lower number of lunar impact basins than expected, and
allows metal from planetesimals accreted to the Moon after its formation
to be removed to the lunar core, explaining the apparent deficit of such
materials in the Moon compared to Earth.