This is the Great Cretaceous Extinction.

At the center is a huge raw crater, suggestive of asteroid collision debris. 

The crater is half-filled with sea-water in which plesiosaurs search for  warmth and food.

The sky is reddish black.

Sooty snow covers the ground and dirty glaciers press down from the mountains.

Dead forests are everywhere and the  dinosaurs are plagued by small rodents (who rob eggs, etc).

Things are pretty tough.