Over 200 million years ago, the dinosaurs were the most dominant species on Earth, but unexpectedly went extinct, nowhere to be found. There are many theories as to how such a dominant species could just vanish from the face of the Earth, but the most accredited theories to explain this wild and sudden mass extinction in the scientific community include The Alvarez Theory and the Great Dying. The most accepted disaster theory in the scientific community is the Alvarez Theory. This theory states that a giant asteroid, about 6 to 9 miles in diameter, weighing up to 4 million tons hit the Earth 65 million years ago, wiping out the existence of dinosaurs.
Because of the impact caused by an asteroid of its size, it is believed that it made a crater about 150 miles wide, reaching deep down into the Earth’s core, shooting out 400 trillion tons of rock and dust. The asteroid would’ve sent up vast clouds of iridium rich dust (a rare metal that only comes from space) that blanketed the Earth’s atmosphere blocking the sun’s light.
Doing so, the asteroid may have heated the Earth’s atmosphere, just enough to cause acid rain and the effects of this event is believed by many to have killed many forms and species of life on Earth. The prime evidence that best supports the Alvarez theory is the fact that sedimentary rocks contain a large amount of iridium metal in the clay bands that have been found by geologists. The bands of iridium in the sedimentary rocks date back to exactly 65 million years ago, which is when the asteroid that caused the mass extinction occurred, according to The Alvarez Theory.
Some pieces of evidence that conflict with the accuracy of the Alvarez Theory is the amount of marine plants that require uninterrupted sunlight, but were somehow unaffected.
The second piece of evidence that contradicts the Alvarez Theory is that the iridium deposits appeared to have been caused by volcanoes. Now, you may be thinking, how could iridium be present on Earth without the direct impact of an asteroid from outer space hitting Earth? The iridium is believed to have been present from former, smaller asteroids hitting the Earth, and had been making its way into the mantle throughout that time, which lead to magma and other substances erupting out of volcanoes. This also appears in another theory, The Great Dying. The final piece of evidence that challenges The Alvarez theory was the gradual extinctions of various forms and populations of life during the same time period that the Alvarez Theory states the asteroid hit in. “The Great Dinosaur Extinction Controversy’’, by Charles Officer and Jake Page states that if such a catastrophe were to occur, the living things that went extinct long ago would have gone extinct much quicker than expected.
An additional theory explaining the extinction of dinosaurs is The Great Dying, otherwise known as The Permian–Triassic extinction. In this theory, it states that the culprit for the devastation of the dinosaurs was volcano induced climatic changes. The Great Dying was between the Permian and Triassic periods, when a massive volcanism released the Siberian Traps (large region of volcanic rock located in Siberia, Russia), gas fires and explosions caused a runaway greenhouse effect. The runaway greenhouse effect was also partly caused by the sudden release of methane from the sea floor, which is when the oceans begin to boil away, causing the Earth to reach abnormally, high temperatures, thus killing away life. All of these natural occurrences are believed to have stemmed from many gradual changes happening at the time, such as a change in sea level, depletion of oxygen in the Earth’s oceans, and severe climate change.
There are many other hypotheses’ out there regarding what actually happened to the dinosaur population, but these two theories are widely believed to be most valid by the scientific community. Despite dinosaurs being the most dominant species on Earth at the time, they still were no match to nature. The Alvarez Theory believes that a huge asteroid hit the Earth blanketing the atmosphere with dust and iridium, thus stopping sunlight from entering, and killing the dinosaurs. There are a few questions surrounding The Alvarez theory such as, the amount of time it took for the dinosaurs to go extinct after this giant asteroid hitting the Earth, and how some marine life and plants survived that require uninterrupted sunlight.
The Great Dying is the second theory I explain that talks about volcanoes and seafloor methane creating a runaway greenhouse effect, which in this case, would have been the reason for the death of the dinosaurs. After carefully collecting the data about each one of the theories, I believe that The Great Dying, and The Alvarez Theory both occurred. I think there is evidence that both of these events did happen and the evidence for it has been stated in the article above. First, the iridium metal that’s present in the sedimentary rock samples gives a hint that a foreign object must have have hit the Earth during the time of extinction. The reason I think it that both happened is because the gradual parishing of different species which leads me to believe that both disasters occurred, but just on a smaller scale, which then compounded together to create the largest mass extinction in history.