How did dinosaurs die – was it due to volcano

Till now, it was believed that sixty-six million years ago, a 5-mile (8km) wide asteroid crashed into the Earth at 70,000 miles per hour (112,600 km/h), and turned into vapor on impact. That vapor and the heavy dust from the impact blocked out the sun and set off a disastrous chain of events that finally led to the extinction of the dinosaurs. However, researchers in the US have now found more evidence for the theory that major volcanic eruption began just before the impact, possibly also playing a role in the extinction.
The research team has precisely dated rocks from the Deccan Traps - a region of west-central India that preserves remnants of one of the largest volcanic eruptions on Earth. They have examined the rocks and have tried to locate a rock that might contain zircon - a uranium-containing mineral that forms in magma after an eruption. If found, that can be used as a very precise dating tool.
It was a tough ask and the researchers collected more than 50 samples of rocks from the region that represented the largest pulse of volcanism. Fortunately, samples from both the bottom and top of this volcanic layer did contain zircon. This helped the team to pinpoint the timing of the beginning and end of the Deccan Traps eruptions.
Based on their analysis, the researchers have been able to determine that the eruption began 250,000 years before the asteroid strike and continued for 500,000 years after the giant impact. The scientists at MIT and Princeton University have also calculated that the volcano spewed out a total of 932,000 square miles (1.5 square km) of lava which, in turn, led to the extinction of dinosaurs.