- An 18km-wide object dug a hole in Earth's crust some 100km across and 30km deep
- This bowl then collapsed, leaving a crater about 200km across and a few km deep
- The crater's central zone rebounded and collapsed again, producing an inner ring
- Today, much of the crater is buried offshore in the Gulf, under 600m of sediments
- On land, it is covered by limestone deposits, but its rim is traced by an arc of sinkholes
The effort to drill into the Chicxulub Crater off the coast of Mexico has been declared an outstanding success.
A UK/US-led team has spent the past seven weeks coring into the deep bowl cut out of the Earth's surface 66 million years ago by the asteroid that hastened the end of the dinosaurs.
The outer rim (white arc) of the crater lies under the Yucatan Peninsula itself, but the inner peak ring is best accessed offshore
Rocks nearly 1,300m below the Gulf seafloor have been pulled up.
The samples are expected to reveal new insights on the scale of the impact and its environmental effects.
The original target was to get down to 1,500m, cutting through a feature called the "peak ring" in the process.
This ring was created at the centre of the impact hole where the Earth rebounded after being hit by the city-sized space object.
In earlier geophysical surveys that were able to sense below the seabed, the feature looked like an arcing chain of mountains.
Rocks from the ring have certainly been sampled. And even if the 1,500m mark was not reached, the team believes it has more than enough material now to answer its key science questions.
The space object that slammed into the planet at the end of the Cretaceous Period instantly dug out a hole 100km wide and 30km deep.
The debris hurled outwards would have darkened the sky and chilled the climate for months on end, driving many creatures to extinction, not just the dinosaurs.
But the precise details of how the event progressed can now be refined by examining the drill cores.
From the rocks, the research team should be able to tell better how the crater formed, the energy involved in its excavation, and the volume of material that was dispersed.
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