Hadean Zircons Elsewhere in the Solar System

Hadean zircons have been documented from fifteen terrestrial localities in Australia, Asia, Africa, and North and South America, in stony and martian meteorites, and in lunar rocks. Extraterrestrial zircons are characterized by the absence of the positive Ce anomaly, seen in virtually all terrestrial zircons, much higher formation temperatures, and a unique suite of mineral inclusions. Remarkably little effort has been directed toward characterizing the geochemical nature of Hadean zircons from terrestrial localities beyond the Jack Hills region and thus it remains unclear how representative it is of the Hadean world. A massive analysis campaign is indicated to better understand Earth’s last true ‘dark age’.