Extinction of the dinosaurs

2008/06/01 Lakar Iraizoz, Oihane - Elhuyar Zientzia

• Geologia
• Paleontologia
• Arkeologia

In the sediments of the time of the disappearance of the dinosaurs, cenospheres have been found that only occur by burning of fossil fuels. (Photo: Microlab northwest )

An international group has made the last proposal: it has discovered in the sediments of the time when the dinosaurs disappeared some grains of hydrocarbons (cenosphere) that only occur by burning of fossil fuels. This has made them think that perhaps one of the triggering factors was a great fuel fire that occurred at that time.

Epoch of great changes

For approximately 160 million years, dinosaurs dominated the Earth. And about 65 million years ago they disappeared, apparently suddenly. Along with these gigantic animals many other living animals were destroyed. It seems that it was one of five violent disappearances that have occurred in the history of the Earth.

Although they do not know it at all safe, because they cannot see what happened in time ago, most scientists believe that a meteorite was responsible, at least in part, for the disappearance. In many places on Earth, a layer rich in iridium was discovered in the sediments of the time. Iridium is a very low mineral on the terrestrial surface and much more abundant in meteorites. Therefore, they concluded that an asteroid hit the Earth. The location of the crash was also determined: In Chicxulube, on the Mexican peninsula of Yucatán. There they found a crater of 280 kilometers of diameter.

In Chicxulube, the impact of the meteorite could occur on the Yucatán peninsula in Mexico. In the image obtained by satellite you can see the crater on the left side of the image. (Photo: ANDÉN)

However, as already mentioned, scientists do not believe that the simple impact of the meteorite was violent enough to cause the decline. They think the collision triggered other events and made proposals. A phenomenon supposedly occurred was global warming. The heat from the collision, apparently, caused large forest fires that caused the massive release of carbon dioxide into the atmosphere. The accumulation of carbon dioxide in the atmosphere caused a warming of the climate that dinosaurs could not withstand.

Another proposal is that perhaps those great fires generated many hollines and that the soot covered the sunlight. Without sunlight the terrestrial plants died and thus the dinosaurs were left without food. In fact, if it had actually been exposed, the effect would spread throughout the food chain, since plants are the basis of the food chain.

Along with the dinosaurs many other living beings were destroyed. (Photo: P. P. Trusler )

Another option is the group that has found the cenosphere. Because the formation of the cenosphere necessarily requires the burning of fossil fuels, it is considered that in the area affected by the asteroid there was a large fossil fuel reserve (currently exists). The collision first caused the evaporation of fuels and, subsequently, the fire in the atmosphere. Thus, a large ball of fossil fuel fire was formed and expanded for hundreds of kilometers. In fact, 13 deposits from all over the world have been analysed and cenospheres have been found in nine. In addition, these pellets are found in the sediments of that time, neither earlier nor later.

They do not know if the fireballs killed the dinosaurs (burning forests, warming the climate or covering the solar fire with soot), but they have shown that at that time fossil fuels were burned. That was the problem with the proposals made so far: they consider that the forests were burned, they have found traces of soot, but they have found very few plants calcined in the sediments of that time. They have taken a step forward.

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