A new study suggests that the large crater on Greenland, more than 100 kilometers wide, may not be a meteorite crater. If so, it’s not the oldest crater on Earth.
A study published in July 2012 in Earth and Planetary Science Letters suggests that a crater more than 100 kilometers wide near Maniitsoq, Greenland, is the result of an asteroid impact about 3 billion years ago. After the study was published, the crater was considered to be the oldest crater ever found on Earth.
However, a new study published in the same journal on March 1 this year says that the characteristics of the crater mentioned in the previous study as a meteorite crater can also be explained by the viewpoint of natural formation.
For example, there are some anomalies in the crater’s magnetic field, previously thought to be evidence of an impact with an asteroid; some of the rocks have an unusual crystal structure, also thought to be caused by a violent impact event.
Chris Yakymchuk, an assistant professor of geology at the University of Waterloo in Canada and one of the authors of the new study, said the magnetic field anomaly in the crater is an illusion, and that the magnetic field there is not anomalous if viewed on a larger scale; as for the peculiar structures of the rocks, they believe they could have formed under Natural conditions can also be formed.
Yakimchuk added that, moreover, some impact craters have common features that this one in Greenland does not have. “Almost all impact craters have tiny mineral structures like zircon, but this one doesn’t.” Zircon (Zircon) is chemically composed of zirconium silicate (ZrSiO4) and can contain traces of iron, manganese, calcium, uranium, thorium and other components.
If there is general agreement that the crater in Greenland is not a crater, then the title of “oldest crater on Earth” would belong to the Yarrabubba impact crater in Western Australia. This crater is 2.23 billion years old.
Recent Comments