And what did they do with aquatic taxa, non-salt tolerant plants, and all the other things that would have died outside of the ark?
The earth stayed vaporized for a while longer than just the flood?
Given that Uranium, Thorium, and Potassium are the most common radioactive elements, we can get an estimate of the energy released by looking at them. Both Uranium and Thorium require about 1 half-life to go by in six months, and Potassium-40 about 4 to produce the measured ages. Given their abundance in the earth and earth’s mass, that is roughly 6x10^44 becquerels. Alpha decays emit about 10 MeV each. Hence, 4.5x10^32 joules get poured into the earth in that time. For reference, that is slightly more than Earth’s binding energy, or about the amount of sunlight that hits the earth every billion years. That is also enough to raise temperatures at 1000K/s, re-melting the crust in about a second and vaporizing the earth in 10. By the end of six months, the ball of plasma once known as earth would be (assuming that it stayed the same size) about 22.5 kK and shining as brightly as a small star.