It is now generally accepted that catastrophic impact events in the geological past have, at various times, greatly perturbed global environments and the biosphere. Painstaking research over more than two decades has established a chronological coincidence between some recognized impact structures and extinction events as revealed by the fossil record, notably Chicxulub and the K/T boundary. However, many fundamental questions remain to be answered about the actual causal mechanisms of impact-related extinctions. Some impact events, such as the Miocene Ries/Steinheim impacts, are not linked with extinctions, even though these might have generated a combined explosive power equivalent to around 250...

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