According to new research, the impact of a meteorite hitting Earth’s rocks when it arrives determines its severity, and not only how large it is.
The Earth has been bombarded by rocks from space throughout its 4.5 billion year history, generating atmospheric dust and covering the surface with debris.
A team of experts wanted to discover why meteorites are responsible for mass extermination events such as that which killed the dinosaurs.
The University of Liverpool studied 44 historical impacts in the last 600 million years.
Researchers discovered that meteorites struck rock rich in potassium feldspar lead to mass extinction events regardless of how large the meteorite is.
A new study has shown that the composition of meteorites hits Earth when they arrive on Earth will determine how severe it is. This goes beyond its size.
The central mineral in mass extinctions is potassium feldspar. It’s non-toxic, but it acts as an ice-nucleating aerosol which strongly influences cloud dynamics.
This allows the clouds to reflect more sunlight, warming the planet.
This also increases the atmospheric vulnerability to climate change, like large volcanic eruptions.
University of Liverpool sedimentologist, Dr Chris Stevenson co-authored the international study.
According to him, “For many decades, scientists have been trying to figure out why some meteorites are responsible for mass extinctions and other, larger ones don’t.”
“It is surprising that life continued as usual during the fourth largest impact, with a diameter of 48 km. A mass extinction occurred only five million years ago with an impact twice the size.
There are many reasons why certain impacts can lead to mass extinctions, which include volcanic eruptions.
Non-toxic, potassium feldspar is the central mineral to mass extinctions. It acts as an ice-nucleating aerosol and strongly influences cloud dynamics. It opens up clouds to more solar radiation which, in turn, warms the planet and modifies the climate. It also increases the atmospheric vulnerability to climate change caused by greenhouse gas emissions like large volcanic eruptions.
Over its history of 4.5 billion years, the Earth has been bombarded from outer space by rocks. This has created atmospheric dust and covered it with debris.
Dr Stevenson said, “Using this method to assess the mineral content in meteorite-ejecta blankets we show how every time a meteorite strikes rocks rich with potassium feldspar it correlates a mass destruction event.”
The team explained that this opens up new research avenues, and also explains what kills life in each impact episode.
According to researchers, meteorites are the only thing that have altered the aerosol climate regime.
“However, current human activities are a similar mechanism to increasing the atmospheric emissions of mineral aerosols,” said Dr Stevenson.
The paper will be published in the Geological Society of London.