In the current study, scientists examined the "pollen and spores" of fossil plants in the layers of mud that infilled the crater. They found that immediately after the impact, ferns quickly colonised the devastated landscape.
Ferns have an amazing ability to bounce back after catastrophe. Layers full of fern spores - dubbed "fern spikes" - are considered to be a good "markers" of past impact events.
However, there was an unexpected discovery in store for the scientists.
They located a second "fern spike" in a layer one metre above the first, suggesting another later impact event.
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