zircon tagged posts

This is astronaut Alan B. Shepard Jr. on the moon in 1971 with the Apollo 14 mission. Credit: NASA

Formation occurred 4.51 billion years ago, 40 million to 140 million years older than scientists previously thought A UCLA-led research team analysed minerals from the moon called zircons that were brought back to Earth by the Apollo 14 mission in 1971. The moon’s age has been a hotly debated topic, even though scientists have tried to settle the question over many years and using a wide range of scientific techniques. “We have finally pinned down a minimum age for the moon; it’s time we knew its age and now we do,” said Mélanie Barboni, geochemist in UCLA.

The moon was formed by a violent, head-on collision between the early Earth and a “planetary embryo” called Theia, a UCLA-led team of ge...

This highly shocked zircon, from the Vredefort Dome in South Africa, shows thin, red bands that are a hallmark of meteorite impact. Photo: Aaron Cavosie

A study of zircons from a gigantic meteorite impact in South Africa casts doubt on the methods used to date lunar impacts. Durable crystals zircons are used to date some of the earliest and most dramatic cataclysms of the solar system. One is the super-duty collision that ejected material from Earth to form the moon roughly 50 million years after Earth formed. Another is the late heavy bombardment, a wave of impacts that may have created hellish surface conditions on the young Earth, about 4 billion years ago.

Both events are widely accepted but unproven, so geoscientists are eager for more details and better dates...