Did asteroid impacts cause the Triassic extinctions?

Nature : A little more than 65 million years ago, a catastrophic asteroid impact on Mexico’s Yucatan Peninsula brought the reign of dinosaurs to an end, making way for the age of mammals. Paul Olsen and Dennis Kent of Columbia University’s Lamont-Doherty Earth Observatory in Palisades, New York, have theorized that an earlier, Triassic extinction event may have also been caused by asteroid impact, rather than by the volcanic activity that accompanied the breakup of the supercontinent Pangaea. Evidence of such an impact may lie in a recently re-dated impact crater in Rochechouart, France. Once thought to be 214 million years old, it’s been dated at between 199 million and 203 million years old, which overlaps with the Triassic extinctions. Also, the late-Triassic fossil record in the UK contains disturbances in the form of grainy, irregularly sized material oriented in a way that seems to indicate they were caused by the impact at Rochechouart. On its own, however, the Rochechouart impact doesn’t seem to have been large enough to cause the extinctions; it may have been one of several blows to the global ecosystem.