Lunar zirconology

Abstract

Compared with zircons found in a variety of rocks on Earth, lunar zircons have received relatively little attention over the last four decades since samples were delivered by the Apollo missions. Nevertheless, the comparatively small number of studies carried out following these missions and in particular made over the last five years has demonstrated enormous potential of zircon research for understanding of lunar magmatism, impact history and provenance of lunar breccias. These studies have identified zircon age patterns that shed new light on the history of the Moon and raise new questions related to our understanding of lunar evolution. In particular, (i) the youngest limit for Lunar Magma Ocean (LMO) crystallisation was determined as 4417 ± 6 Ma; (ii) several periods of intensified magmatic activity at about 4.34, 4.20 and 4.00 Ga were identified in the post-LMO history of the Moon; and (iii) several pre-3.9 Ga impacts have been identified on the Moon. Here we discuss some of these results, questions and new directions, and propose an approach for further lunar zircon research.