An international team of researchers has found the first fossil proof that a massive asteroid which hit in the area of the Yucatan Peninsula 66 million years ago killed the dinosaurs, and they have found it, in of all places, along the Brazos River in Central Texas.
Researchers have been convinced since the 1980s that what is called the Chicxulub Impact, which involved a six mile wide meteor hitting the Earth with enough power to blast a six mile wide impact crater and created energy equaling a billion times that of an atomic bomb sent dust shooting into the atmosphere, instantly blotting out the sun and creating an instant global cold snap, wiped out the dinosaurs and brought an end to the Cretaceous Period. But until now, they have not found hard evidence for it.
But Johan Vellekoop, a PhD candidate in paleoclimatology at Utrecht University in the Netherlands, told 1200 WOAI news by phone that he and other researchers have found the fossilized remains of tiny sea creatures which lived in the 100 meter deep sea which is now the Central Texas plateau.
“We found the first actual evidence for what is called an ‘impact winter,’ Vellekoop said. “At the impact itself in Mexico, a tsunami was triggered which rolled across the Gulf of Mexico into the sea which is now Texas.”
He says lipids, or fats created by the life process, from a micro organism called Thaumarchaeota, have been found preserved in the sediment on what was then the floor of the sea and is now the Brazos River Valley. “These are produced by microorganisms that life in the sea. They adjust the lipids in their cells to the temperature of the ocean. When they die, those lipids sink to the sea floor and are preserved in sedimentary rocks.”
He says using those lipids, they can recreate the temperature of the sea.
“Before the impact, this sea in Texas was about 30 degrees Celsius, nice and warm, but just following the tsunami, there is a drop of seven degrees, really strong cooling. We argue that this is caused by all of the dust that was launched into the atmosphere by the impact, blocking the sunlight.”
Vellekoop says researches focused on Central Texas because it was determined to be close enough to the Chichxulub site to be able to show its impact, but was not too close that the sediment would have been destroyed by force of the tsunami.
“In Mexico, the impact destroyed the sea floor and everything was swept away. Here in Europe, the sea floor was very quickly, and here there are hardly any sediments preserved.”
He says the massive amount of dust which was blown into the atmosphere would have either immediately killed the cold-blooded dinosaurs, or, probably, more likely, would have killed off their food supplies, starving them to death.
“Such a strong cooling was very strong, and the most important thing is not the cooling itself, but what caused the cooling,” he said. “The cooling was caused by darkness, and plants and algae need sunlight to grow. So all of the cooling caused the plants to die. So it was a combination of facts which both caused the dinosaurs to freeze to death, and the ones that survived lost their food supply.”