Scientists say they have a clue that may enable them to find traces of the asteroid that wiped out the dinosaurs in the very crater it made on impact.

This pointer takes the form of a nickel signature in the rocks of the crater that is now buried under ocean sediments in the Gulf of Mexico.

An international team has just drilled into the 200km-wide depression.

It hopes the investigation can help explain why the event 66 million years ago was so catastrophic.

Seventy-five percent of all life, not just the dinosaurs, went extinct.

The UK-US led team gave an update on its research here at the Fall Meeting of the American Geophysical Union in San Francisco.

The group is currently running all manner of lab tests on the hundreds of metres of core pulled up from under the Gulf in April and May.

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