Scientists drill "dino" crater

Earlier this year, scientists successfully drilled into a giant crater made by the asteroid that killed off the dinosaurs. Researchers are now studying the rock samples that were taken during the 2-month drilling project, looking for clues about life on Earth 66 million years ago.

The team, from Imperial College London and the University of Texas, believe that the rock samples will provide new insights into this period of Earth's history – including more information on how the dinosaurs became extinct.

How was the crater made?

The Chicxulub (pronounced “Chick-sah-loob”) crater in Yucatán, Mexico, was created when an asteroid the size of a small city smashed into Earth. The asteroid, estimated to be 10–15 kilometers wide, punched a massive hole in the Earth’s crust around 100 kilometers across and 30 kilometers deep

What happened next?

Scientists believe that the asteroid’s impact set off huge waves and forest fires. It would have also sent large amounts of dust and rock into the air, blocking out the sun. Without sunlight, many plants would have died – and without plants, many animals would have died too, due to lack of food.

This series of disasters is thought to have wiped out three quarters of Earth’s species, including most of the dinosaurs.

By drilling down into the Chicxulub crater and studying layers of rock from around the time of the impact, scientists hope to discover new evidence to support this theory.

The peak ring

The team were particularly interested in a part of the Chicxulub crater called the “peak ring”.

A peak ring looks like a circular chain of mountains. It is formed when rock beneath the surface of the Earth bursts up into the air after an impact. The rock then collapses back down in the shape of a ring, a bit like the circles you get when you drop a pebble in water.

Chicxulub is the only known crater on Earth with an intact peak ring. There was just one problem: most of Chicxulub’s peak ring lies beneath the Gulf of Mexico, buried under hundreds of meters of ocean sediment. Getting rock samples wasn’t going to be easy – so the team called on "Myrtle”.

Drilling back through time

“Myrtle” is a lift-boat - a type of vessel that can lift itself out of the water on legs. This provided a secure platform to drill from.

First, the drill was lowered through 15 meters of water. Next, it drilled through 500 meters of ocean sediment. Finally, it hit bedrock for the first time.

The team carried on drilling to a depth of 1300 meters, taking rock samples at every stage. Each sample took them further back in time.

"It's been quite magical," said co-chief scientist Joanna Morgan from Imperial College London.

What will the rock samples tell us?

The core samples were first sent to Texas, USA, so that researchers could use a CT scanner to examine their inner structure. Next, the samples were shipped to the University of Bremen, Germany, where a team of 33 scientists began more in-depth investigations. Half the samples are being analyzed now, while the other half have been put into storage so they can be studied in the future.

The team hopes that the rock samples will provide answers to questions like:

• How much energy did the asteroid impact release?
• What volume of dust and debris was thrown up into the atmosphere?
• How long did it take for life to return to the area after the impact?

Already, the research has given scientists a much clearer understanding of how peak rings form. The team has also found fossil evidence that suggests there were microorganisms living inside the crater shortly after the asteroid’s impact. In fact, the asteroid may have actually created new habitats for these organisms, by making lots of tiny spaces in the rocks in which living things could flourish. Clues like these can help us understand how life on Earth managed to recover all those millions of years ago.

Glossary

Asteroid
A rocky or metallic object in the Solar System that orbits the Sun. There are millions of asteroids in the Solar System.

Impact
An object coming into contact with another at great force.

Crater
A large bowl-shaped hole in the ground, usually made by an explosion or something falling from the sky.

Sediment
Small particles of rock that accumulate in bodies of water, such as riverbeds or the ocean floor.

Core sample
A piece of a naturally occurring substance removed by a special drill and brought to the surface for examination.