*BOOM! You can hear a loud boom sound coming from something. And you question in a panic…is it the end of humanity like the end of the dinosaurs? has the end come? are we all going to die? was it an asteroid?*
I was wondering what I was gonna do for this post on until a few minutes ago, then it just clicked.
Today, in this SCIENCE! entry, we will discuss the different theories for how the dinosaurs died. This is yet another controversy/debate that nobody has really found the answer to yet.
That being said, let’s jump right in!
When learning about the dinosaurs when you were younger, you most likely have heard the following theory:
“There was a large asteroid that had such a forceful impact on Earth that killed all of the dinosaurs.”
This is probably the most popular of all the theories, but there are several explanations for the end of the dinosaurs.
THEORY ONE-The Asteroid Theory.
THEORY TWO-The Volcanic Activity Theory.
THEORY THREE-The Competition Theory.
THEORY FOUR-The Continental Drift Theory.
Yeah, this is probably going to be a long post.
THEORY ONE-The Asteroid Theory.
It is widely believed that this was the cause of dinosaur extinction, and there is plenty of evidence of this in the Chicxulub crater just off the Yucatán Peninsula in Mexico.
Scientists decided to go and drill inside the crater and examine the minerals within.
Pbs.org, in a chain of articles for “What Killed The Dinosaurs”, explained many minerals that point to the theory of the impact.
- “The metal iridium, which is similar to platinum, is very rare on Earth’s surface but is more common in asteroids and in molten rock deep within the planet. Scientists have discovered levels of iridium 30 times greater than average in the Cretaceous/Tertiary (KT) boundary, the layer of sedimentary rock laid down at the time of the dinosaur extinction” (PBS, 2).
“These pieces of once-molten rock, called impact ejecta, are evidence of an explosion powerful enough to instantly melt bedrock and propel it more than a hundred miles from its origin. Ranging in size from large chunks to tiny beads, impact ejecta are common at or near the Cretaceous/Tertiary (KT) boundary, the geological layer that defines the dinosaur extinction” (PBS, 2).
“[Fractured] crystals, often called “shocked quartz,” show a distinctive pattern of fracturing caused by high-energy impacts or explosions. Some scientists maintain that the fracture pattern in these quartz crystals could only have been caused by a massive asteroid or comet impact” (PBS, 2).
- “Some paleontologists see evidence in the fossil record that dinosaurs were doing quite well prior to the end of the Cretaceous — that they were in no way declining in abundance when the impact occurred” (PBS, 2). This will come into play later to combat the ideas of gradualism as opposed to catastrophism, (the dinosaurs died gradually, as opposed to the idea that the dinosaurs ended abruptly in a catastrophic event).
That’s quite a lot of evidence in favor for the idea of collision with an celestial object. Thanks PBS. Check out the actual chain of articles here. I will be referencing back to this article throughout this post. I used it to format this entire thing.
Okay, so what exactly would’ve happened as a result of that impact?
Summarizing from this, what happened was that the impact triggered magnitude 10 earthquakes, causing much destruction already, followed by large tsunamis. As part of the crust was hit this forcefully, the rocks would fly upwards and eventually rain down all over the world. These pieces of rocks would fly down so fast, that is caused the atmosphere to heat, practically baking the planet. All of that dust and smoke would then rise up and block out the sun.
And that’s one theory of how the dinosaurs went extinct.
THEORY TWO-The Volcanic Activity Theory
You can actually link the above theory to this one! The impact of the asteroid would perpetrate the tectonic plates, causing those earthquakes and tsunamis, and it would also cause volcanic activity.
However, those who don’t believe in the idea of the impact, believe that volcanic eruptions were to blame.
“Immense lava flows cover nearly 200,000 square miles of the Deccan region of India, reaching depths of more than 6,500 feet in places. Lava flows like these provide evidence of a rash of volcanic activity for at least 500,000 years leading up to the extinction of the dinosaurs” (PBS, 3).
- “Some scientists think the presence of high concentrations of iridium at the geological layer associated with the dinosaur extinction could be the result of extremely large-scale volcanic activity” (PBS, 3).
- “Although geologists generally acknowledge that a comet or asteroid impact would cause [shock quarts/fractured crystals], some scientists conclude that they could also be the result of volcanic eruptions” (PBS, 3).
- Volcanic eruptions would’ve also caused the global warming effect that would heat the atmosphere and kill off the dinosaurs.
That’s certainly a plausible theory, BUT it doesn’t stand well on it’s own. It leaves the crater unexplained, if you believe just this theory independently.
THEORY THREE-The Competition Theory
This is an idea from gradualism.
“Faced with an evolving group of competing organisms — the mammals — perhaps dinosaurs were driven to extinction by competition. Packs of small mammals would have competed with dinosaurs for food. And carnivorous mammals would have preyed on dinosaur eggs. Not only did mammals likely compete with dinosaurs for resources, many species survived the end-Cretaceous extinction and subsequently came to dominate Earth” (PBS, 4).
However, there isn’t much supporting this claim. There isn’t any clear evidence showing how much competition dinosaurs actually had, this is just an idea that they competed for resources. That probably did happen, BUT was it really enough to cause dinosaur extinction? If this was the case, there would be dinosaurs that would be left if it got to the point where it was fighting until there was one remaining. That dinosaur would die if they were carnivorous because there would be nothing to eat, but that leaves the crater from 65 million years ago unexplained.
THEORY FOUR-The Continental Drift Theory
You can definitely see Scientific models of how drastically the continents shifted in the time of the dinosaurs. “As continents heaved upward, pushed by the movement of tectonic plates, ocean currents were redirected and global sea levels fell. The Interior Seaway, for example, which once divided North America in half, simply drained away as the Colorado Plateau rose thousands of feet” (PBS, 5). This, of course, would mean change of climate, and the deaths of many species.
“The presence of 65- to 70-million-year-old fossilized ocean creatures thousands of feet above present-day sea level strongly suggests that ocean levels fell dramatically as the Cretaceous period came to a close. According to many scientists, continental drift and ocean regression would have caused continents to become drier, cooler, and less hospitable to dinosaur life than they had been previously” (PBS, 5).
I’ve noticed while writing this that these theories all link together and are all dependent, because the chances are slim that it was just one thing that ended the dinosaurs. I think there were too many dinosaurs for that. So, I think all of these theories were all different factors to the extinction. Just a fact of life is that it declines at some point-some of the things stated above, like sea levels, continents drifting, and the idea of competition all weakened the dinosaurs down. And to end it all, I think that’s when a catastrophe came in as the final blow.
But what do you think?
Do you agree with me, or do you believe in one of those theories? Let me know in the comments.
This post took a very long time to write, wow.
If you made it this far, THANK YOU! I hope you enjoyed it.
Have wonderful lives.
*no, Weird Account just fell. humanity hasn’t ended yet.*
*side note: 1,300+ words O.o*