'One-of-a-kind' meteorite unveils violent past of Earth's solar system
A volcanic meteorite recovered in Western Australia has helped researchers uncover the fierce past Earth's solar system.
Captured on camera in 2007 falling on the WA side of the Nullarbor Plain, the Bunburra Rockhole Meterorite had unique characteristics that suggested it came from a large asteroid that has never before been identified.
The research team dated the meteorite with the argon-argon technique, a well-known method for dating impact crater events, to offer a glimpse of the asteroid's impact history. They obtained three series of ages indicating that the meteorite recorded three impact events between 3.6 billion and 3.4 billion years ago.
Associate Professor Fred Jourdan said that nearly all the meteorites that they locate, come from Vesta, the second largest asteroid in the solar system but after studying the meteorite's composition and orbit, it appeared that it derived from a large, unidentified asteroid that was split apart during the collisions.
He further added that the ages are pretty old by terrestrial standards, but quite young for a meteorite since most are dated at 4.57 billion years old, when the solar system began and the results also showed that not a single impact occurred on this meteorite after 3.4 billion years ago until it fell to Earth in 2007.
It was also established that the reason for impacts stopping after 3.4 billion years ago could have been from the asteroids being too small in size to be a target for collisions, or protected by regolith, a thick blanket of cushiony powder usually found at the surface of asteroids.
(Posted on 09-08-2014)