Tim,
Take a look at this. It is the latest results on the one-two punch of asteroid first leading to volcanoes that killed most of the dinosaurs and other species over a 50,000 year period, 66 million years ago. Before the impact, the eruptions produced about 71,000 cubic kilometers of lava—an average rate of about 400 million cubic meters each year. But starting about 50,000 years after the asteroid impact, Deccan volcanoes and fissures began spewing lava at an average rate of about 900 million cubic meters per year
http://news.sciencemag.org/climate/2015/10/volcanoes-and-asteroid-strike-may-have-done-dinosaurs