The Pin
January 22 2020, 4:48 pm
The huge crater Yarrabubba, located in western Australia, was formed by the fall of a meteorite more than 2,200 million years ago, the oldest known impact in the world, according to the authors of a new research published Tuesday in the scientific journal Nature
A team of Australian scientists from the University of Curtin, in the city of Perth, has determined that the age of Yarrabubba is 2,229 million years, exceeding 200 million years any other similar crater on Earth.
The researchers were able to identify the precise age of the Yarrabubba, 70 kilometers in diameter, thanks to the analysis of zircon and monacite, minerals extracted from the crater bed. The team looked for evidence of the recrystallization of their textures, since when an impact is powerful enough, the structure of these minerals can be altered.
Using the high resolution and sensitivity ionic microsonde (SHRIMP), the scientists scanned the crystals and found some uranium, thorium and lead content. With the help of special formulas, experts were able to calculate the age of the crystals, which coincides with the age of the crater.
“Earth ice ball”
The researchers also believe that the collision of the meteorite against Earth could have caused a change in the regional or global climate of our planet, which in those times, according to the hypothesis of the ‘Iceball Earth’ (or global glaciation) , was totally or partially covered with ice.
“If the impact had occurred on an ice sheet, it would have released huge amounts of water vapor, which is an even more efficient greenhouse gas than carbon dioxide,” the study’s lead author and researcher told AFP. NASA Johnson Space Center, Timmons Erickson.
–
