Most scientists believe that the Cretaceous extinction event wascaused by a 6 mile wide asteroid that impacted Earth at what is nowthe Yucatan Peninsula 65.5 million years ago. The impact would havethrown tremendous amounts of dust high into the atmosphere, whichwould have blocked the sun for months. Without sunlight, the plantswould have died, and without the plants, so would any herbivorousanimals. The carnivores would have then died, too.Another theory popular with scientists is that climate changewas the cause of the extinction. Before the asteroid impact, a hugevolcanic trap (a large lava flow) called the Deccan Traps had beenerupting for about three million years. The amount of carbondioxide it released into the atmosphere caused tremendous globalclimate change, and dramatically decreased the variety of dinosaurspecies.It is also very plausible that it was a combination of these twofactors.