Earth's crust have been outside of the asteroid impact.So that the crust comes from the breakdown of the inner core of a huge eruption of hot magma out.Weak on the crust of an enormous force,so that the crust there have been a strong change.His The performance is great earthquakes and volcanic eruptions.I think because of the growth of the dinosaur era,inclusive of the surface of the Earth's crust is thin and fragile.Frequent strong earthquakes and volcanic eruptions.