This study opens new avenues for research on the causes of mass extinctions and the killing of some life forms on Earth, in addition to the impact of meteorites in changing the aerosol regime.
according to study New published by the Journal of the Geological Society in London, the composition of the rocks that the meteorite hits when it reaches Earth determines the lethality of its impact, not just its size.
After researchers from the University of Liverpool and their colleagues from Spain’s Technological and Renewable Energy Institute analyzed the impact of meteorites that struck Earth over the past 600 million years, they found that meteorites that collide with rocks rich in potassium feldspar always perform to mass extinction regardless of the size of the meteorite itself.
Meteorites caused mass extinctions
The history of the Earth’s geological record indicates that about 66 million years ago, the Earth experienced an event known as a mass extinction, which was considered a large-scale extinction of animal and plant species in a geologically short period of time and the end of the existence of many types of living organisms on the planet.
In addition, five other mass extinctions occurred on Earth, which are known as the Small Extinctions.
The WhatsApp Press release For the University of Liverpool, the Earth was subjected to meteorite bombardment throughout its long history of about 4.5 billion years, which led to the generation of dust in the atmosphere and covering the surface with debris, which scientists consider a major cause of the mass extinctions that the Earth witnessed, in addition to other cosmic and climatic reasons.
As stated in a report Science Alert. These mass extinctions are often attributed to the effect of winters, as vast amounts of exploding Earth dampen sunlight, starve plants and algae, and plunge the planet into cold.
As for the effects of meteorites in mass extinction events, this happened in different proportions, and even some meteorites that struck the Earth did not cause extinction. Therefore, the team wanted in this study to find out the reason for the impact of some meteorites leading to a mass extinction, such as the one that killed the dinosaurs, while others were less lethal, and this was one of the things that puzzled scientists.
“For decades, scientists have been baffled as to why some meteorites cause mass extinctions, and others, even large meteorites, do not,” says Dr Chris Stephenson of the University of Liverpool’s School of Earth, Ocean and Environmental Sciences, lead author of the study.
Assessment of the mineral content of dust upon impact
According to the press release from the University of Liverpool, the research team with expertise in palaeontology, asteroid layers, mineralogy, cloud microphysics and climate modeling, sought to explore what caused some meteorites to mass extinctions, for example, the impact of the asteroid Chicxulub, which killed Dinosaurs, using a new method called evaluating the mineral content of dust ejected into the atmosphere upon impact.
“It’s amazing when we put the data together, life went on as normal during the fourth largest meteorite impact on Earth, which left a crater 48 km (30 miles) in diameter,” explains Dr. Stevenson.
The scientific team of the University of Liverpool and their colleagues from the Spanish Institute of Technology and Renewable Energy analyzed the dust resulting from 44 meteorite impacts over a period of 600 million years, in order to search for the impacts of meteorites that struck the Earth, specifically their impact on minerals in the earth’s soil and the metal dust left behind.
“Using the mineral content assessment method, we show that every time a meteorite, big or small, hits rocks rich in potassium feldspar, it correlates with a mass extinction event, regardless of the size of the meteorite itself,” says Dr. Stevenson.
Potassic feldspar is a common and fairly harmless mineral that makes up about 60 percent of the Earth’s crust and is common in soils. And unlike other materials that have been broken down in our atmosphere by meteor impacts, such as acid rain causing hydrocarbons, it acts as a powerful ice nucleus aerosol that severely affects the dynamics of clouds, allowing more solar radiation to pass through. This in turn warms the planet and changes the climate, and the atmosphere also becomes more sensitive to warming from greenhouse gas emissions, such as large volcanic eruptions.
Dr. Stevenson explained that this study opens a completely new avenue for research into the causes that led to the mass extinction and the killing of some forms of life on Earth, in addition to the impact of meteorites in changing the aerosol climate system. “However, current human activities represent a similar mechanism with increased emissions of metallic aerosols into the atmosphere,” Stephenson added.
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