Over time there have been many theories as to how the dinosaurs became extinct, some of these include terrestrial stresses (such as lower sea level or global temperature) and radiation (Pasichnyk, 2011), but the 2 theories that have become the most widely accepted as they have the most amount of supporting evidence are the Impact Theory (otherwise known as the Alvarez Hypothesis (Smith, 2005)) and the Volcanic Theory (Pasichnyk, 2011).
The Impact Theory states that millions of years ago a comet or an asteroid struck the Earth and the impact of that is what killed the dinosaurs, it also caused the meteor to evaporate covering the earth in a layer of dust (Smith, 2005). In Mexico there is a crater with a diameter of 180km called Chicxulub that has been dated to have first surfaced 65 million years ago leading scientists to believe that whatever caused the crater lead also to the extinction of the dinosaurs. Iridium, a rare metal that is also found in asteroids, has also been discovered as a layer covering the whole surface area on the Earth. Asteroids contain Iridium, a rare metal, this same metal has been found in a layer surrounding the Earth, the layer is believed to have been created when the …show more content…
The Volcanic Theory answers many questions that the Impact Theory poses, for example, volcanic activity acts over a much longer time span than an impact does, which would explain the irregular iridium peaks found in areas of the globe; and it also accounts for the selective extinction that occurred (refer to example of amphibians that did not become extinct during the Mesozoic period) (Pasichnyk,
The Impact Theory states that millions of years ago a comet or an asteroid struck the Earth and the impact of that is what killed the dinosaurs, it also caused the meteor to evaporate covering the earth in a layer of dust (Smith, 2005). In Mexico there is a crater with a diameter of 180km called Chicxulub that has been dated to have first surfaced 65 million years ago leading scientists to believe that whatever caused the crater lead also to the extinction of the dinosaurs. Iridium, a rare metal that is also found in asteroids, has also been discovered as a layer covering the whole surface area on the Earth. Asteroids contain Iridium, a rare metal, this same metal has been found in a layer surrounding the Earth, the layer is believed to have been created when the …show more content…
The Volcanic Theory answers many questions that the Impact Theory poses, for example, volcanic activity acts over a much longer time span than an impact does, which would explain the irregular iridium peaks found in areas of the globe; and it also accounts for the selective extinction that occurred (refer to example of amphibians that did not become extinct during the Mesozoic period) (Pasichnyk,