The asteroid that may have killed the dinosaurs came from beyond Jupiter

The Chicxulub crater, left behind by the impact, contains elemental traces that suggest the origins of the notorious projectile.

Aug 16, 2024 - 02:30

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The asteroid that may have killed the dinosaurs came from beyond Jupiter

Chemical clues left interior the impact crater can help trace the gap rock’s origins

An illustration of an asteroid slamming into the ocean on the aspect of Mexico.

Some Sixty six million years prior than, an even asteroid slammed into Earth, making a necessary crater simply off Mexico (shown on this artist’s illustration).

Mark Garlick

Earth’s most reasonable killer asteroid got here from the outer reaches of the solar formulation, researchers listing interior the Aug. Sixteen Science.

About Sixty six million years prior than, an asteroid slammed into the ocean simply off Mexico’s Yucatán Peninsula, forming the Chicxulub crater. That truly productive impact can have brought about a mass extinction tournament on Earth, killing off increased than 60 share of the planet’s species, inclusive of all nonbird dinosaurs (SN: 1/25/17). The impact left geochemical fingerprints, which consists of enhanced phases of the area iridium, in a skinny layer of rock realized in diverse countries across the globe (SN: 9/Eight/Eighty 4).

Now, new chemical analyses of these rock layers, which mark the boundary between the Cretaceous and Paleogene durations (additionally is as a rule known as KPg), are helping to create a forensic profile of the killer asteroid.

Geochemist Mario Fischer-Gödde of the Collage of Cologne in Germany and colleagues measured 5 isotopes, or varieties, of ruthenium interior the KPg rock layers, as neatly as in 5 impact craters that came about between 36 million and 470 million years prior than and in Earth-based platinum ores (SN: 12/18/18).

Ruthenium, like iridium, is a platinum-community area, infrequent in Earth’s crust despite the fact that abundant in asteroids and diversified space rocks. On the diversified hand, the relative abundance of ruthenium isotopes varies between space objects reckoning on the place they originate.

The ruthenium signatures interior the KPg rocks were indistinguishable from one but one diversified, tying them all to the equal tournament, the crew realized. And that tournament was once definitely extraterrestrial, now not from ashfall as a culmination of excessive volcanic eruptions which have additionally been implicated interior the dinosaurs’ demise (SN: 9/28/23).

A photo showing the rock layer containing geochemical evidence of an asteroid impact Sixty six million years prior than. — Rock layers across the sphere comprise geochemical fingerprints of the asteroid impact Sixty six million years prior than. Best the following, the tip of a rock hammer aspects to a skinny, whitish rock layer containing enhanced phases of iridium in an outcrop north of Drumheller in Alberta, Canada. That layer marks the geologic boundary between the Cretaceous and the Paleogene durations.Francois Gohier/Science Source

Most meteorites realized on Earth are stony, or siliceous, asteroids, originating from the close consequently of asteroid belt between Mars and Jupiter. That belt was once additionally the origin of the 5 non-Chicxulub impactors.

But the Chicxulub impactor was once a carbonaceous asteroid, originating interior the outer reaches of the solar formulation, from an historic asteroid belt previous Jupiter (SN: 12/Sixteen/22). Now that’s some distance out.