Impacte météorite sur terre

The composition of rocks determines the severity of a meteorite impact

Long considered a factor triggering massive extinctions meteorites have caused a lot of damage over the course of Earth’s history. Recently, a team of scientists sought to understand why certain meteorites caused massive extinctions. These graduates of the University of Liverpool and ITER of Tenerife have therefore undertaken research on meteorite particles.

During their study, the researchers used a new method to assess the mineral content of dust ejected into the atmosphere during 44 impacts during Last 600 million years. The team discovered that rock mineralogy that a meteorite hits, rather than the size of the impact, determines gravity of the last.

For this research, the scientists used their expertise in paleontology, mineralogy, asteroid stratigraphy, cloud microphysics. In addition, the results of this study were published in the Journal of the Geological Society of London.

A possible correlation with mass extinctions

For decades scientists have wondered why some meteorites cause massive extinctions and others of greater importance not.

“Many destruction mechanisms have been proposed, such as large volcanic eruptions, but like meteorites, these do not always correlate with mass extinctions. [..] It is surprising when you put the data together. Life continued normally during the 4th largest impact with a crater diameter of around 48 km. While twice the impact was associated with mass extinction, only 5 million years ago. “

Dr Chris Stevenson, Sedimentologist in Liverpool

Potassium feldspar, a powerful component

According to this new method, scientists have discovered that meteorites that hit rocks rich in potassium feldspar always correspond to a mass extinction episode, regardless of their size. K-feldspar is a non-toxic component. However, this is a powerful mineral aerosol with an ice core, which has a strong influence on the movement of clouds.

“Using this new method of evaluating the mineral content of meteorite ejecta blankets, we show that each time a meteorite, large or small, strikes rocks rich in potassium feldspar, it is correlated with a mass extinction event. “

Dr Chris Stevenson, Sedimentologist in Liverpool


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