When talking about meteor craters, the Chicxulub crater, sited off the northern coast of Yucatan, Mexico, is probably the most vast ever discovered on this planet. Indeed, it is widely accepted that this now sediment filled section of the Gulf of Mexico is the precise location for the mass extinction event that was to bring about the demise of the dinosaurs, plus thousands of other species of flora and fauna.
Around 65 million years ago an immense meteor was thought to have crashed into this part of the Earth’s surface with such a devastating impact. The meteor has been estimated as being around 10 km in diameter and as it was travelling towards the planet at around 30 km per second, this led to a crater formation that is far bigger than any other still visible today.
The meteor would have hit with such tremendous force, none of us could ever begin to imagine. Vast portions of the Earth’s crust would have been ejected into the atmosphere from the impact and signs are visible in rocks all over the World, of just how immense this event would have been. So much heat and power would have been created from this mighty explosion, that tiny diamonds have literally been found in rocks thousands of miles away. This proves that calcium carbonate would have been subjected to such extreme pressures and temperatures in order to create these microdiamonds.
Immediately after the impact, massive earthquakes would have been felt across much of the planet’s surface. It is also thought that huge tsunamis would have been generated, through the force of the meteor strike, and that these would have been immensely worse than the waves that hit Asia at the end of 2004. The atmosphere would have been cloaked in darkness for many months after the explosion and certain species of life would have struggled desperately to cling on to their existence. Indeed, many species failed to make it.
By far the biggest clue for this impact was the fact that iridium had also been discovered in these 65 million year old rocks. Considering this element is so rare in our planet’s crust, it did not make sense that so much iridium was being found in rocks of this age all over the World. This eventually led scientists to believe that there had been a huge meteor impact around this time and this is because this element is known to be highly prevalent in meteorites. A search was undertaken to discover the location of the crater site and the Chixculub crater was eventually identified as being the most likely location for this apocalyptic event.
In terms of the history of evolution on this planet, this meteor impact came at a time where many living species were already struggling to hold onto their existence. In fact, it has become more and more apparent that dinosaurs themselves were already under threat at this time. There is a lot of conjecture as to the reasons for many mass extinctions before the Chicxulub meteor hit, but it is commonly accepted that this event speeded up the demise of many species.
The meteor impact marks the boundary between the Cretaceous period and the Tertiary period in the history of life and you may very well see it referred to as the ‘K-T’ mass extinction event. Whilst this disastrous event would have been so horrendous for all life on the planet at that time, strangely enough, it could be one of the most fundamental reasons for the marked flourishing of mammals straight after. In fact, you may even be able to go further and state that if this meteor impact had never happened, we humans may not be roaming this planet today.
Christopher L. Shelby, M.D.