Martian Meteorite Age Puzzle Solved
July 25, 2013

Meteorite Offers Clues To Evolution Of Martian Surface

John P. Millis, Ph.D. for - Your Universe Online

Occasionally, a meteorite is found on Earth with peculiar origin: Mars. Anytime a large object such as an asteroid or comet impacts the surface of Mars, chunks of rock are ejected into outer space. Over time, some of these stones will make their way to Earth, impacting the ground as meteorites.

We know that these specimens are from Mars based on their composition and other factors. So they provide an excellent laboratory for exploring various elements of the Red Planet without having to make costly trips through the solar system. Yet, such studies are not without controversy.

There have been debates about the age of some of the meteorites that have impacted Earth. But a new study from the Royal Ontario Museum (ROM), led by Curator Dr. Kim Tait, studied meteorite NWA 5298 - discovered in northwest Africa in 2008 - and may bring an end to questions surrounding its history.

"With the ROM's capacity and expertise in the field of Martian meteorites, research carried out on NWA 5298 was a timely opportunity for The Museum's Mineralogy department to further expand our expertise and to collaborate with international colleagues. Through this study published in Nature, we have unlocked an important key towards understanding the application of geochronology and of the Red Planet itself," said Dr. Tait.

The team was able to determine that the rock was created about 200 million years ago from an ancient Martian lava flow. But, they also found traces of crystalline structures that were created during the ejection of the rock from the Martian surface. This allowed them to narrow down the age of that event to some 20 million years ago.

Tait and her colleagues are now turning their attention to another, recently acquired, Martian rock known as NWA 7042. Also from northwest Africa, the researchers hope that further study will complement their recently published work, and help establish a timeline for the evolution of the Martian surface.

"I am excited about securing the NWA 7042 as part of the ROM's Martian meteorite collection," said Tait. "This is important for us in ROM Mineralogy toward our continued study of Mars itself and the solar system at large, as well as providing an advanced understanding of Martian formation and evolution of Mars."