Chicxulub

It is calculated the asteroid/comet that struck the Earth at the K/T boundary was about 14 km across. The Chicxulub crater has a diameter of 200 km. See https://q-mag.com/the-latest-on-chicxulub.html … the crater is now covered by younger sedimentary material and was not spotted until 1991. Drilling on the crater took place in the 1990s, and again in 2002. It was then decided to do a fuller investigation in 2016 and the cores are now stored at the Univeristy of Bremen in Germany. The impactor created an enormous ring around the outside of the crater – and another ring inside the crater. The surface was crushed inwards to a depth of 30 km – and rocks behaved like liquids. A gigantic fountain of rock shot up into the atmosphere and then fell back in on itself. It left a 400 m high ring inside the crater. In an area of 1500 km around the crater the pressure waves and blast was so intense it snuffed out all life on the spot. Areas further apart were hit by tsunamis of an inconceivable dimension. At the same time, enormous amounts of dust and ashes were thrown up into the air and as it rained back down some of it was burning. There was a sharp drop in global temperatures over the following years as a result of so much debris trapped in the upper atmosphere (obscuring the heat of the Sun). There was also a flood of acid rain – followed by cold. Remarkably, although the K/T boundary marks the disappearance of many life forms it also marks a surprisingly fast return of new life forms.