An artist's rendering of the moment of impact when an enormous space rock struck the Yucatán peninsula at the end of the Cretaceous.
Click on image for full size
Courtesy of Don Davis, NASA
News story originally written on March 4, 2010
For decades, scientists have known that an enormous space rock
crashed into the ocean off the Yucatan Peninsula more than 65 million years ago
, resulting in the the K-Pg extinction
We know that more than half of the plant and animal species on Earth died out then, but we don't know what caused the extinction. Now, a team of 41 scientists from 12 nations has prepared a paper that suggests that the K-Pg extinction was caused by a single impact near what is now Chicxulub, Mexico.
In their paper, the scientists point out that when the asteroid hit the Earth near Chicxulub, it exploded and threw huge amounts of dust and asteroid material into the air. When all of that material settled back to Earth, it formed a clay layer that can still be seen in rocks around the world. Within the layer, scientists have found high levels of iridium. This heavy element is not normally found in high concentrations at Earth's surface, but it is found in asteroids and comets.
The impact between the asteroid and the Earth created a crater that is more than 180 kilometers in diameter. It also caused tsunami, earthquakes and fires; extended (but not total) darkness; cooling temperatures and acid rain. It would have also changed the Earth's climate.
Shop Windows to the Universe Science Store!
Our online store
on science education, classroom activities in The Earth Scientist
specimens, and educational games
You might also be interested in:
Why did the dinosaurs go extinct? No one knows for sure, but there are some explanations that seem to make sense. At the time the dinosaurs and lots of other species died out (which is sometimes called...more
An element (also called a "chemical element") is a substance made up entirely of atoms having the same atomic number; that is, all of the atoms have the same number of protons. Hydrogen, helium, oxygen,...more
Scientists have learned that Mount Hood, Oregon's tallest mountain, has erupted in the past due to the mixing of two different types of magma. Adam Kent, a geologist at Oregon State University, says this...more
The Earth's mantle is a rocky, solid shell that is between the Earth's crust and the outer core. The mantle is made up of many different reservoirs that have different chemical compositions. Scientists...more
Some faults look strong and like they wouldn’t cause an earthquake. But it turns out that they can slip and slide like weak faults causing earthquakes. Scientists have been looking at one of these faults...more
The sun goes through cycles that last approximately 11 years. These solar cycle include phases with more magnetic activity, sunspots, and solar flares. They also include phases with less activity. The...more
Studying tree rings doesn't only tell us the age of that tree. Tree rings also show what climate was like while the tree was alive. This means that tree rings can tell us about climates of the past. Two...more