This abrupt change could well have been written about in the bible. I believe that the epochical timelines are squashed together and happened far more quickly than scientists want us to believe. During the flood, the earth changed in more than one aspect. The old earth was no more. instead, was an earth with more seas, more rivers, more mountains and more lakes. The forces unleashed in the depths by the water pressure would have shifted the plates around, like crashing India into Asia and creating the Himalayas, for example. An earth with more species of animals and insects. The old predators are gone. Not saved on the ark. God started afresh.
Genesis 7 v11 says "In the six hundredth year of Noah's life, in the second month, on the seventeenth day of the month, on the same day all the fountains of the great deep burst open, and the floodgates of the sky were opened."
The deeps opened up releasing methane and water - hydrogen & oxygen. The heavens opened up, releasing more water.
After the flood, the animals released from the ark, prospered in the wetter climes. Insects increased. Large older predators like dinosaurs and woolly mammoths became extinct. More methane is produced. The earth warmed up globally, for 150,000 years as per the Nat Geo article before the atmosphere was able to control the temperature and balance out the gases again.
The article goes on to depict that the earth is close to experiencing the same levels again through our use of burning fossil fuels. We know what's happening next, when we read Revelation 21!