Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Globally unique double crater identified in Sweden

11.09.2015

Researchers at the University of Gothenburg have found traces of two enormous meteorite impacts in the Swedish county of Jämtland, a twin strike that occurred around 460 million years ago.

The researchers have discovered two craters in Jämtland. One is enormous, while the other is a tenth of the size of the first.


by Don Dixon, copyright Erik Sturkell.

"The two meteorite impacts occurred at the same time, 458 million years ago, and formed these two craters," says Erik Sturkell, Professor of Geophysics at the University of Gothenburg.

Erik Sturkell and his research colleagues 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.

An era of meteorites
The two meteorite impacts 458 million years ago were not the only ones to strike Earth at this time.

"Around 470 million years ago, two 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 500 metres at the points where two meteorites simultaneously stuck. Double impacts like this are very unusual. This is the first double impact on Earth that has been conclusively proved.

"Information from drilling operations demonstrates that identical sequences are present in the two craters, and the sediment above the impact sequences is of the same age. In other words, these are simultaneous impacts," says Erik Sturkell.

The water was forced away during the impact, and for a hundred seconds these enormous pits were completely dry.

"The water then rushed back in, bringing with it fragments from the meteorites mixed with material that had been ejected during the explosion and with the gigantic wave that tore away parts of the sea bed," says Erik Sturkell.

Impacts at several locations in Sweden
Several meteorites have also been found on Kinnekulle.

"In the 1940s, an unusual-looking red limestone slab was found in a quarry. A few years later, researchers understood that there was a meteorite in the slab. Large meteors explode and disintegrate almost completely, while small meteors fall as rocks, such as in this limestone," says Erik Sturkell.

Around 90 meteorites from meteorite impacts have been found on Kinnekulle over the past fifteen years.

"Small meteorites survive the fall, while large ones explode and disintegrate. In Jämtland we have only found minerals from the meteorites, small grains of chromite.

The fact that active quarrying is conducted on Kinnekulle is the reason why researchers have found meteorites there. And as a discovery was made as long ago as the 1940s, the individuals working in the quarry know what to look for.

So might it be possible to distinguish slabs in our limestone floors that might come from meteorites?
"Technically speaking, yes, although there is probably not much chance, as the limestone slabs that come from meteors are often rather ugly and will probably have been discarded. But they do exist!"

Contact
Erik Sturkell, Professor at the Department of Earth Sciences, University of Gothenburg
Tel.: +46 (0)31-786 2820, E-mail: erik.sturkell@gvc.gu.se

Weitere Informationen:

http://www.gu.se/english/about_the_university/news-calendar/News_detail//globall...

Henrik Axlid | idw - Informationsdienst Wissenschaft

Further reports about: asteroid belt craters diameter fragments meteorite meteorite impacts meteorites sequences

More articles from Earth Sciences:

nachricht Impacts of mass coral die-off on Indian Ocean reefs revealed
21.02.2017 | University of Exeter

nachricht How much biomass grows in the savannah?
16.02.2017 | Friedrich-Schiller-Universität Jena

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Impacts of mass coral die-off on Indian Ocean reefs revealed

21.02.2017 | Earth Sciences

Novel breast tomosynthesis technique reduces screening recall rate

21.02.2017 | Medical Engineering

Use your Voice – and Smart Homes will “LISTEN”

21.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>