Erstellt am: 24. 10. 2016 - 17:28 Uhr
The extinction of the dinosaurs
66 million years ago there were dinosaurs and suddenly they appeared to die out. All sorts of large, impressive creatures that roamed the planet, swam in our oceans and flew through the heavens just disappeared. The culprit appears to be a rather large asteroid that, rather unfortunately for the dinosaurs (and probably fortunately for human kind), slammed into the Yucatan peninsula off the Gulf of Mexico. The resulting dent it caused is known as the Chicxulub impact crater,
Currently there is a huge international effort underway to look carefully at this impact crater. And Dr. Ludovic Ferrière, at Vienna’s Natural History Museum is part of the project. He told me about what's going on and the research work to discover as much as scientists can about the cosmic event which resulted in the extinction of the dinosaurs.
Ludovic:
At this particular site in the Gulf of Mexico, it is by far one of the largest impact structures on Earth. In fact, the Chicxulub crater is the 3rd largest, almost 200 kilometrers in diameter. And it had large consequences for the extinction of the dinosaurs. I am working on the results of the recent drilling that was just completed at the end of May of this year.
We have been really interested in this impact structure since it is one of the best preserved that we have on Earth. And this drilling and analysis of the data will help us to understand how impacts formed on Earth and on other planets (and their consequences).
Steve:
The Chicxulub impact crater is in the middle of the ocean in the Gulf of Mexico. So, the drilling work must be a challenge in itself?
Ludovic:
Part of it is in the water but another part of it is buried under sediments. We have been conducting this drilling about 30 kilometers off shore. We had to install a special platform there to perform the drilling. And yes it was quite challenging but this type of drilling has been done in the past already.
Steve:
Is the scientific world united in its belief that the asteroid that created the Chicxulub impact crater is the one that wiped out the dinosaurs?
Ludovic:
The point is that at this time in the Earth’s history, 66 million years ago, (we can say that) this impact event happened. You have to imagine an asteroid 14 kilometers in size impacting in this place and all the related consequences that this may have had at that time. It really is the most striking explanation. In fact, the impact alone is enough to cause the extinction. There will still be a few scientists who do not believe in that, but I think the evidence is out there.
Steve:
How long will it be before you get some concrete results that you can present to the world?
Ludovic:
In the last couple of weeks, we have been splitting the cores (and selecting samples) and describing over 829 meters of these cores. Altogether we have 11,126 pieces of rocks that have been distributed throughout the 31 scientists. Hopefully within the coming weeks, some results will be presented. For my particular investigations, it will take more than a year because it really is a lot of work under the microscope and using different other techniques to understand the message that these rocks can tell us.
Steve:
So, I guess a lot of these rock particles are going into test tubes to work out what was going on and happening at that impact site?
Ludovic:
Yes, some colleagues are focused on chemical traces, others are looking at fossil sediments that have been deposited just after the impact occurred. There really is a lot of fields of expertise currently looking at this and even some modeling the impact event. Even scientists looking at various minerals that were formed to see if these minerals are a good basis for micro-biology to start from.
Steve:
What is the one major thing you would like to learn from this impact site?
Ludovic:
Personally, I’m interested in the way the rock reacted to the shock induced by the impact. The huge pressure and temperatures that were released during impact. And what happens when contact between an asteroid and its target take place. The first seconds are the most important for me for my research.
Steve:
Interesting that we’ve never seen such an impact on Earth since it happened all those millions of years ago?
Ludovic:
Of such a magnitude right! Nothing has been recorded of such a high impact in the more recent history of the Earth. There were other such events that happened much earlier. The Chicxulub crater is the 3rd largest on Earth but there have been (that we know about) two even larger impact events but they are almost about 2 billion years old. And during that time, there were no dinosaurs around to become extinct.
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