A modern example is arguing that volcanic activity killed off the non-avian dinosaurs and not the Chicxulub impact. That's considered quite controversial today,

A modern example is arguing that volcanic activity killed off the non-avian dinosaurs and not the Chicxulub impact. That's considered quite controversial today, even though volcanoes are implicated in other major extinctions and there was considerable volcanic activity leading up to the Mt. Everest-sized rock or comet hitting the Yucatan peninsula. Also there is the argument that the fossil record shows a lack of dinosaur bones at the K-T boundary, but most paleontologists think the rock or comet did the job. An argument at the other extreme has the impact killing off all non-avian dinosaurs within one hour after the impact across the globe.