Researchers are confident that the question of what killed the dinosaurs is finally closed. Scientists linked their extinction to an asteroid that crashed into Earth 66 million years ago, finding key evidence: asteroid dust inside an impact crater.
Death by an asteroid rather than a series of volcanic eruptions or some other global calamity has been the leading hypothesis since the 1980s. In the 1990s, this connection was strengthened with the discovery of the 125-mile-wide Chicxulub impact crater beneath the Gulf of Mexico, which is the same age as the rock layer. New research confirms the theory from the 80s. Scientists have discovered asteroid dust with a corresponding chemical imprint in the impact crater.
This is the latest study from the 2016 International Ocean Science Program mission. During it, more than 900 meters of stone core was collected from a crater buried under the seabed. Research on this mission helped fill in the gaps regarding impact, impact, and life recovery from an asteroid impact.
The main feature of asteroid dust is the element iridium, which is rarely found in the earth’s crust. Moreover, there is a lot of it in some types of asteroids. In a new study, scientists found a trace of iridium in a piece of rock excavated from the crater. In the crater, a layer of sediment deposited for days or years after the impact is so thick that scientists were able to pinpoint the age of the dust just two decades after the impact.
Dust is all that remains of an 11 km wide asteroid that crashed into the planet millions of years ago, causing the extinction of 75% of life on Earth, including all non-Avian dinosaurs.
The researchers estimate that the dust raised by the impact has been circulating in the atmosphere for no more than a couple of decades. This helps determine the time that the extinction lasted.
The highest concentrations of iridium were found in a 5-centimeter section of the rock core excavated from the top of the crater’s peak ring, a high point in the crater that was formed when rocks rebounded and then collapsed from the force of the impact.
Iridium analysis was carried out in laboratories in Austria, Belgium, Japan and the USA.