The K-T extinction event 66 million years ago, which marked the end of the Cretaceous period and beginning of the Tertiary, was triggered by the impact of huge meteors, the biggest reshaping the Gulf of Mexico, shrouding the world in a wreath of dust and tektites, asphyxiating or drowning 80% of all life under tsunamis as wildfires seared the land — accounting for much of the oil we produce today.