[LUM#6] Inside the Crater

[LUM Magazine] - Published on July 3, 2017 in Science-Society

How was the giant Chicxulub crater formed by the fall of an asteroid 66 million years ago, known to have probably caused the extinction of the dinosaurs? This is the focus of an expedition in which Johanna Lofi, a geophysicist from Géosciences Montpellier, took part.

It was the last global cataclysm to date. Some 66 million years ago, a giant asteroid struck the Earth, causing the extinction of most species of the Cretaceous period and probably ending the reign of the dinosaurs. The Chicxulub impact crater formed in a matter of minutes, reaching 180 km in diameter. 

For the first time, an international team of researchers has drilled into the central ring of this crater, now buried under 600 meters of sediment in the Gulf of Mexico. Scientists and drillers spent two months at sea in 2016 (as part of the International Ocean Discovery Program's scientific drilling programs International Ocean Discovery Program and International Continental Drilling Program), drilling day and night into the famous central ring to extract rock samples... up to 1.3 km below the seabed.

 "Of the three largest craters on Earth, this is the only one associated with mass extinction, "explains Johanna Lofi, a geophysicist at the Montpellier Geosciences Laboratory, who took part in the expedition. "It is also the only one whose central ring has been preserved by the marine sediments that covered it." The study of the samples will provide a better understanding of how giant craters are formed and enable a detailed reconstruction of the history of this asteroid impact and the mass extinction that followed. The initial results were published in the journal Science in 2016 (The formation of peak rings in large impact craters).

Keywords: Geosciences, LUM#6, LUM Magazine, Research, Science