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Science & Technology

66-Million-Year-Old Fish Fossils Linked To Asteroid That Killed Dinosaurs

Saturday 30/March/2019 - 07:57 PM
Sada El Balad
Technical Times
Researchers of a new study find evidence that the “killing field” at a site in North Dakota is linked to the asteroid that killed the dinosaurs 66 million years ago. This is the first fossil graveyard of large organisms linked to the impact at the end of the Cretaceous period.

'Killing Field'
In 2013، paleontologist Robert DePalma unearthed a fossil graveyard at a digging site in the Hell Creek Formation. There، he discovered the fossilized remains of fish stacked one over the other، along with conifers، burned tree trunks، dead mammals، insects، mosasaur bones، marine microorganisms، marine cephalopods، and the partial remains of a triceratops.

Even back then، he had a suspicion that this clumping of dead creatures in one area may have been a result of the asteroid impact that wiped out the dinosaurs.

“At no other K-T boundary section on Earth can you find such a collection consisting of a large number of species representing different ages of organisms and different stages of life، all of which died at the same time، on the same day،” said DePalma.

Iridium And Tektites
All around the world، rocks that are 66 million years old tend to have excess iridium in them، possibly a result of the asteroid impact since iridium is rare on Earth but is common in asteroids and comets. Then there are also tektites، which are small glass beads that rained down from the melted rock.

What’s interesting about the fossil discovery is that while both sediment layers have excess iridium، only the lower layer had tektites، likely from an inland moving force. What this means is that the fossils were a result of two different events.

The first one resulted in the lower layer، which happened mere hours after the impact، and the second one is the upper layer later on when the dust was already settling after the impact.

In addition، some of the fish’s gills had glass beads in them، suggesting that they were directly impacted by the rain of glass beads.

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