It was complicated to survive for the dinosaurs in the Lost World.
There are a lot of theories about why the dinosaurs extinction occurred, but a widely accepted theory, is that an asteroid 6-15 km in diameter hit the Earth about 65 million years ago, creating the Chicxulub crater at the tip of Mexico_s Yucatán Peninsula.
The impact would have penetrated the Earth_s crust, scattering dust and debris into the atmosphere, and causing huge fires, tsunamis severe storms with high winds and highly acidic rain , seismic activity, and perhaps even volcanic activity. The impact could have caused chemical changes in the Earth_s atmosphere, increasing concentrations of sulfuric acid, nitric acid, and fluoride compounds.