Splosh! How the dinosaur-killing asteroid made its crater

[nitpicker]

https://www.bbc.com/news/science-environment-45986449

Splosh! How the dinosaur-killing asteroid made its crater

By Jonathan Amos
BBC Science Correspondent

25 October 2018

It is hard to imagine billions of tonnes of rock suddenly start to splosh about like a liquid - but that is what happened when an asteroid struck the Earth 66 million years ago. Scientists have now put together a detailed picture of the minutes following the giant impact.
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The analysis of rocks drilled in 2016 from the leftover crater show they underwent a process of fluidisation. The pulverised material literally began to behave as if it were a substance like water.

Models had predicted what should happen when a 12km-wide stony object from space punched the ground. Initially, a near-instantaneous bowl would have been created some 30km deep and up to 100km wide. Then, instabilities would have seen the sides collapse inwards and the base of the hole rebound skyward, briefly reaching higher than the Himalayas. When everything had settled down, a crater roughly 200km wide and 1km deep would remain.

This is the feature that is now buried under sediments in the Gulf of Mexico, close to the port of Chicxulub.

The impact description - scientists call it the dynamic collapse model of crater formation - is only possible if the hammered rocks can, for a short period, lose their strength and flow in a frictionless way. And it is the evidence for this fluidisation process that researchers now report after studying the rocks they drilled from something called the "peak ring" - essentially, a circle of hills in the centre of the remnant Chicxulub depression.
(snip)

[Marcuse]

1. Cool. Just like on the Moon.