Meteorite impacts tagged posts

This is a photomicrograph of a vesicular green shard from the Onaping Formation of the Sudbury impact basin. Credit: Paul Guyett, Trinity College Dublin

Meteorite impacts can produce more than craters on Earth – they can also spark volcanic activity that shapes its surface and climate by bringing up material from depth. An international team, led by geochemists from Trinity College Dublin studied rocks filling one of the largest preserved impact structures on the planet, located in Sudbury (Ontario, Canada). The ‘bolide’ hit Earth here 1.85 billion years ago and excavated a deep basin, which was filled with $melted target rocks and, later, with jumbled mixed rocks full of tiny volcanic fragments.

Not only are there volcanic fragments throughout the sequence of the 1...

The researchers have discovered 2 craters in Jämtland. One is enormous, while the other is a tenth of the size of the first. “The 2 meteorite impacts occurred at the same time, 458 million years ago, and formed these two craters,” says Prof Erik Sturkell. They found one of the craters 20 kilometres south of Östersund in Brunsflo. This is an enormous crater, with a diameter of 7.5 kilometres. The smaller crater is located 16 kilometres from there, and has a diameter of 700 metres.

“Around 470 million years ago, 2 large asteroids collided in the asteroid belt between Mars and Jupiter, and many fragments were thrown off in new orbits. Many of these crashed on Earth, such as these two in Jämtland,” says Erik Sturkell.

Jämtland was under the sea at the time, with a water depth of 500m at th...