The Extinction of Dinosaurs: Exploring the Catastrophic Effects of the Asteroid Impact

The Catastrophic Event that Killed the Dinosaurs: An Asteroid Impact

About 66 million years ago, life on Earth was brought to a halt by a catastrophic event when a 12 kilometers (7.5 mi) wide asteroid crashed into the ocean near Mexico’s Yucatan Peninsula.

The Extinction of the Dinosaurs

The aftermath of this impact eventually wipes out three out of four plant and animal species worldwide, ending the dominance of that most famous group of creatures, the dinosaurs.

The Loss of Ecological Niches

Our modern world lacks the big, toothy, scaly animals that trample and roam the countryside. According to the fossil record, dinosaurs once occupied many ecological niches around the world.

The Cretaceous-Paleogene (K-Pg) Boundary

The point in time when all this changed reflects the content of a distinct layer of sedimentary rocks called the Cretaceous-Paleogene (K-Pg) boundary.

Uncovering the Evidence

The El Kef site in Tunisia is used to adequately represent the scale of this broad layer, although in fact a layer of compacted dust extends around the planet between 2 and 3 centimeters (about an inch) thick.

Decoding the Timeline

Although they are very thin, a few centimeters of sedimentary rock can pack material for tens of thousands of years. For decades, paleontologists have assumed that the extinction of dinosaur species occurred relatively gradually.

Discovering the Impact

In the 1970s, American geologist Walter Alvarez was busy studying the chaotic formation of rock layers in the Italian mountains, layers that included the K-Pg boundary.

Evidence in the Elements

Alvarez and his father predicted that iridium would be one in ten billion particles. And what they found was 30 times the concentration. Even more shocking is that this element is found in concentrated amounts in the same layer all over the planet.

An Explosion of Iridium

And this explosion of iridium means more than the usual delicate dust of cosmic balls. A supernova can be ruled out because no trace of the plutonium-244 isotope has been found, other than a burst of iridium that left a surprising dose of space rock.

Unveiling the Impact Crater

Shortly after Alvarez and his father published their hypothesis, an oil company discovered traces of a 180 kilometers (110 mi) wide crater under the Yucatán River.

The Extent of Destruction

Today, few people discuss the fact that about 66 million years ago a large asteroid fell on our planet, and the time of this collision coincided with the mass extinction event. There is still debate about how exactly a medium-sized meteorite could cause such a carnage.

Causes of Extinction

How did an asteroid impact lead to the extinction of many species?

Global Climate Change

The pallor of dust and smoke in the atmosphere will cause major changes in the global climate, altering temperatures and food chains in ways that will rapidly kill many species.

Signs of Impact

And there is a lot of evidence that the Earth was rocked by the K-Pg impact. “Tsunami waves” refers to the sheer force of the explosion. Chemical signs of a global phenomenon of particles blocking sunlight confirm the possibility of a planetary winter. There are even signs of drastic changes in the chemical composition of the ocean, which explain the mass death of marine life.

Debates and Hypotheses

But are these changes, however vast, sufficient to explain the extent of the destruction? Sure, it was a big part of rock, but life proved surprisingly resilient in the face of big changes.

Vulnerable Dinosaurs

There is some argument that dinosaurs, especially the large ones, were particularly vulnerable to large-scale environmental change and may already have been on their way to extinction. A collision with an asteroid pushed him to the limit. This hypothesis is still highly debated, and the evidence is difficult to interpret in one way or another.

The Location Matters

One of the hypotheses of recent years suggests that it is not the size, but the exact location of such an impact that really shakes the planet’s atmosphere. Even medium-sized chunks of rock from space can cause long periods of dangerous cooling if they enter a geological environment containing the right minerals.

The Future of Impact Events

Near-Earth asteroid monitoring programs tasked with providing us with information on potentially devastating impacts show that there is nothing to worry about in the near future.

Preparing for the Future

However, given enough time, we can expect the Earth to experience a similar effect again. And if we can’t use technology to avoid impacts, we need to prepare for some kind of environmental impact.

Source: Science Alert

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