Mysterious Extinction of Dinosaurs

Since the Vesuvius Volcanic eruption in AD 79 which completely destroyed the ancient city of Pompeii with a population of 20,000, scientists have constantly observed and studied Mount Vesuvius. Scientists discovered that the earth core contains an abundance of iradium. Volcanic eruption can bring a large amount of iridium to the earth surface. Did iridium in the K-T boundary come fromvolcanic eruptions? So is it possible that vocalnic eruptions led to the global extinction of the dinosaurs?