DThe Earth's Middle Ages ended 66 million years ago with a catastrophe of unimaginable proportions. At that time, a diameter of about 60 kilometers asteroid collided with the earth. With a speed of 70,000 kilometers per hour, the car hit the sea off the Mexican peninsula of Yucatán. The consequences of this event have long been consensus among researchers. So not only the dinosaurs died out, worldwide there was such a large species extinction that a new epoch of earth history began. Three groups of researchers have now independently reconstructed the course of the catastrophic events minutely. After that, the world has completely changed in only one day: what began peacefully in the Cretaceous of the Mesozoic Era, ended after an impact event, huge earthquake waves, huge tsunamis and devastating forest fires in a short time in the Paleogene of the Earth's New Age. Not only did the surface of the earth change, but the acidity of the oceans also rose considerably, which also had catastrophic effects.
What happens when the earth is hit by a large asteroid, scientists can simulate quite well on the computer. Scenarios range from the formation of a crater, the melting of rocks, to those clouds of dust and rock splinters that are thrown miles into the atmosphere. While these calculations are based solely on physical models, the most recent reconstructions of the three research groups are based on geological surveys of rock samples.
Stone rain and huge tsunami waves
Geologists have written the first chapter in the first 24 Hours of Earth New Age Diary with Sean Gulick of the University of Texas at Austin. Gulick and his colleagues analyzed an unusual rock sample from the epicenter of the asteroid impact. This 800-meter rock cylinder had been drilled two years ago as part of the International Ocean Drilling Program, from the sub-sea edge of the impact crater in the Gulf of Mexico off Yucatán. Normally, sediments settle on the seabed at a rate of a few centimeters per millennium. In this core, however, the researchers found a layer just under 130 meters thick, which apparently only arose within a day, maybe even in just a few hours.
Like the researchers around Gulick in the “Proceedings” of the American Academy of Sciences From the sequence of different layers in this layer of rock, the sequence of dramatic events following the asteroid impact can be reconstructed in detail: Thereafter, the impact energy was apparently so great that the seawater evaporated at the impact point and melted the limestone of the seafloor. The rock acted like a liquid.
As the analyzes show, the lowest layer of the core consists of the remnants of the molten rock that sloshed to the surface immediately after impact and formed the base of the crater rim. Above it is a 40-meter-thick layer of remnants of the melt, which is mixed with irregularly shaped rocks with sharp corners and edges, the so-called breccias. According to Gulick and his colleagues, this is rock that was thrown into the air on impact and “rained” within ten minutes.
. (tagsToTranslate) Sean Gulick (t) University of Texas (t) Mesozoic (t) Rock (t) Apocalypse (t) Disaster (t) Geology