Lmao at the size of Mexico. The atmosphere is so thin and that rock so big any mass ionized off of it would be negligible. That's almost instant vaporization anywhere on the planet impact occurs. Nothing survives. Oceans aren't that deep to absorb the
Kinect energy of any impact over a couple thousand feet in diameter....much less a rock the size of Mexico going hundreds (maybe thousands) of times faster than the speed of sound. An asteroid the size of Stone Mountain is a global event. The size of Mt. St. Helen...apocalyptic....the size of Manhattan...molten surface and debris in space for years....size of Mexico