Asteroid dust with iridium finally closed the question of the extinction of dinosaurs

Death from an asteroid and not from a series of volcanic eruptions or some other global calamity was

a leading hypothesis since the 1980s.In the 1990s, this link was strengthened with the discovery of the 125-mile-wide Chicxulub impact crater under 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.

Crater left by an asteroid that destroyeddinosaur, is located on the Yucatan Peninsula and is called Chicxulub after the neighboring city. Part of the crater is on the sea, and part is on land. The crater is buried under many layers of rocks and sediments. A 2016 mission led by the International Ocean Discovery Program extracted rock cores from the crater's coastal area. Credit: University of Texas at Austin / Jackson School of Geosciences / Google Maps.

This is the latest study frommissions of the International Ocean Science Program 2016. 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, consequences, and life recovery after an asteroid impact.

The main sign of asteroid dust is the elementiridium, which is rare in the earth's crust. Moreover, it is quite abundant 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.

Part of the core of the rock, torn out of the crater,left by an asteroid impact that destroyed the dinosaurs. Researchers have found high concentrations of the element iridium - a marker of asteroid material - in the middle of the core, which contains a mixture of impact ash and ocean sediment deposited over decades. Iridium is measured in parts per billion.

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 lifted by the impact has been circulating in the atmosphere for no more than a couple of decades. This helps determine how long the extinction lasted.

Highest concentrations of iridium foundin 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 formed when rocks bounced off and then collapsed from the force of the impact.

Iridium analysis was carried out in laboratories in Austria, Belgium, Japan and the USA.

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