What Killed the Dinosaurs?

Jul 19, 2013 by Fraser Cain
Chicxulub Crater

Dinosaurs roamed the Earth for 135 million years. Filling every ecological niche, from the oceans, forests and plains; even the skies.

Then, 66 million years ago, something terrible happened. In a geological instant, 75% of the plants and animals on Earth went extinct. And all of the land dinosaurs were wiped off the Earth forever.

What happened? What killed them off?

What could have caused that much damage in such a short amount of time?

The key to this mystery was found in a strange layer of ash sandwiched between layers of rock deposited 66 million years ago. This line, known as the Cretaceous-Paleogene boundary, is found across the world in the and it marks the moment when everything DIED. What's interesting about this layer is that it's rich in iridium, a on Earth, but abundant in asteroids.

And so, geologists found the most likely culprit: an asteroid.

This evidence matched the discovery of an enormous asteroid in the Yucatán Peninsula in Mexico, centered near the town of Chicxulub. The rock debris in this area could be dated back to approximately 66 million years old, matching the worldwide layer of ash.

We now know that an asteroid at least ten kilometres across slammed off the coast of Mexico 66 million years ago, releasing 2 million times more energy than the most powerful nuclear bomb ever detonated.

The effect of this impact is mindblowing.

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Millions of tonnes of rock were ejected into space on ballistic trajectories. Reheated by atmospheric re-entry, this debris superheated the air across the entire planet, catching the world's forests on fire.

Shockwaves radiated outward from the impact site, inducing earthquakes and volcanoes along their path. Mega tsunamis thousands of meters high spread out from the impact site, pounding coastlines around the world.

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User comments : 18

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Gmr
3.2 / 5 (18) Jul 19, 2013
Um... where's the original research? In the video? Is it a new advert for a disaster film? The summary doesn't tell me much beyond what we've learned before...
grondilu
5 / 5 (1) Jul 19, 2013
> Filling every ecological niche, from the oceans, forests and plains; even the skies.

From https://en.wikipe...rosaurs:

Pterosaurs are often referred to in the popular media and by the general public as flying dinosaurs, but this is incorrect. The term "dinosaur" is restricted to just those reptiles descended from the last common ancestor of the groups Saurischia and Ornithischia (clade Dinosauria, which includes birds), and current scientific consensus is that this group excludes the pterosaurs, as well as the various groups of extinct marine reptiles, such as ichthyosaurs, plesiosaurs, and mosasaurs.
TheGhostofOtto1923
1.7 / 5 (9) Jul 19, 2013
Um... where's the original research? In the video? Is it a new advert for a disaster film? The summary doesn't tell me much beyond what we've learned before...
Um... why don't you try following the links at the end of the story?

Dinosaurs are still with us as we know. And as grondilu points out, many so-called dinos may have been precursors of modern-day form factors. Are pangolins stegosauruses?
TheGhostofOtto1923
1.8 / 5 (5) Jul 19, 2013
Panglolins, stegosaurs, ankylosaurs, glyptodonts
http://www.macroe...ins.html
shavera
2.9 / 5 (8) Jul 19, 2013
Because of vague body similarity a pangolin is a stegosaur? Might as well call a bat a bird and a dolphin a fish. The skeletons of mammals are definitely distinct from the skeletons of the dinosaurs. They shared a common reptilian ancestor, but they're defninitely not the same thing. Dinosaurs of course have survived into the present as birds are a kind of theropod dinosaur (as much as we're all a kind of fish at least).
Claudius
1.5 / 5 (16) Jul 19, 2013
Interesting how the video tries to work global warming caused by CO2 into the scenario. Typical.
Sinister1811
2.6 / 5 (11) Jul 19, 2013
It is fairly conclusive that the cause of the K-T extinction was due to a comet that collided with the Earth. The only legacy of the dinosaurs that lives on today are the birds. But, whether or not they resemble their reptilian counterparts is a matter of speculation.
foolspoo
1.8 / 5 (8) Jul 19, 2013
It is fairly conclusive that the cause of the K-T extinction was due to a comet that collided with the Earth. The only legacy of the dinosaurs that lives on today are the birds. But, whether or not they resemble their reptilian counterparts is a matter of speculation.


I would imagine not, the onset of this "comet winter" would have forced many species to evolve or...
shavera
3.8 / 5 (6) Jul 19, 2013
Sinister: I don't know if the case is that airtight for comet/meteor impact. We know that there's an impact _correlated_ with the dinosaur extinction, but so too are major events like the Deccan Traps. I really wouldn't be surprised if there's no one "smoking crater" and it's really the combination of factors involved in their extinction.
Sinister1811
2 / 5 (8) Jul 19, 2013
@shavera Yeah, you're probably right. That's the conclusion they've made. But we don't know that for certain. It could be any number of factors that caused the extinction.
TheGhostofOtto1923
2.3 / 5 (9) Jul 19, 2013
Because of vague body similarity a pangolin is a stegosaur? Might as well call a bat a bird and a dolphin a fish
-And you didnt even read the link. So_stay_ignorant. This guy presents a great deal of very compelling evidence.
Feldagast
1 / 5 (5) Jul 19, 2013
I have seen this all before on the Discovery Channel and the History Channel, there were however questions about their facts in the show on TV.
wwqq
2.3 / 5 (4) Jul 19, 2013
Pterosaurs are often referred to in the popular media and by the general public as flying dinosaurs, but this is incorrect.


Birds are dinosaurs.
rwinners
2 / 5 (4) Jul 19, 2013
@Otto
This is a very debated subject. There are many viewpoints. This article simply presents one (basic) one. Don't even know why it is here.
shavera
4 / 5 (8) Jul 19, 2013
Ghost: I did in fact read the article, But all the author points to are broad morphological similarities. He completely ignores the large fossil record that completely distinguishes the lineage of mammals from that of dinosaurs. Principally that mammals are synapsid and dinosaurs are diapsid in their skull shapes. This similar skull shape traces through each lineage very well, very firmly establishing which clade each belongs to. I don't think any evolutionary biologist worth their salt would give the "pangolins are really stegosaurids" argument a second thought. The "evidence" is so underwhelming in the face of all the other data supporting their evolutionary lines that it is quite irrelevant.

This is why we know whales are a lot more like cows than like fish. We can trace back successive ancestors of whales and cows to something common-ish to both. Even though a whale looks more like a fish, and lives in fishy environments, the ancestry is a dead giveaway.
shavera
4 / 5 (8) Jul 19, 2013
Pangolins, similarly are more closely related to cats and dogs than much else on the phylogenetic tree. (see clade Farae for more details) http://en.wikiped...ki/Ferae
TheGhostofOtto1923
1.9 / 5 (9) Jul 20, 2013
Well if you had read the article you would have understood that the fossil record is not that extensive nor that complete. Fossils are being reexamined and fundamentally reinterpreted quite frequently. T Rex was really a predator did you know it? Only the latest shift.

The evidence for pangolin/stegosaur is just as complete as the 100yo interpretation that vertical plates on the back of an animal would have served some function besides being chewy tidbits in combat, rather than armor plate which is the standard and recurring form factor, and which you ought to be able to admit MAKES MORE SENSE.

Early paleontologists got more wrong than they did right which is why everything needs to be rexamined. Salt-worthy scientists understand this and are making new discoveries all the time as a result.

Dinos had feathers. I bet you still don't believe this because the Dino book you got as a kid shows them all leathery like your dead iguana.
Gmr
1 / 5 (5) Jul 26, 2013
Pangolins, similarly are more closely related to cats and dogs than much else on the phylogenetic tree. (see clade Farae for more details) http://en.wikiped...ki/Ferae


That is so unutterably cool I could cry. The Tasmanian Wolf more closely resembles the body shapes of placental carnivores, but the bizarre pangolin is closer on the family tree - Yay convergent evolution!