Fix in your mind that the mountain ranges of the world rose while the new ocean basins floors of cooling lava sank at the close of Noah’s Flood, so the bibliophobes’ ignorant canard that real Noah’s Flood needed to have covered the mountains is specious. When you look at the catastrophic nature of the high energy deposition of the sedimenatry rock laters, and consider that sedimentary means laid down in water, Noah’s Flood is the only logical explanation really for what is observed in the geologic record.
The mountains rose at the close of the Flood because tectonic plates were crashing into others (read carefully http://globalflood.org), and because hot magma was injected from below into the receding floodwater, having formed such as the pillow basalts of eastern Turkey’s Mount Ararat where Noah’s Ark landed, so with the vast sedimentary rock layers stacked like pancakes often grading into each other having been laid down during the flood, entombing billions of creatures in really predictable sequences (see http://detectingdesign.com/fossilrecord.html, the Bible’s global flood model matches the evidence, while uniformitariansim looks foolish really.
The assumptions are unknowable for the methodologies of radioisotope rock dating results which supposedly preclude the historicity of Noah’s Flood circa 2350 b.c.; these unknowable assumptions such as supposed accurate knowledge of the initial ratios of parent/daughter radioisotope material of the rock samples, and that the levels of leaching (by water) of radioactive material from the sample rocks are known, assuming too that the rate of radioactive decay was not differrent in the past. See the big picture here http://genesisveracityfoundation.com.