//It does seem impossible even for a Christian like me//
Possibly because it *IS* impossible, unless you speculate miracle after miracle to make the story/myth fit your belief system?
//It was the Flood that split the continents into the form we know them today//
An assertion that has no basis in fact. And if it WAS the flood that split the continents how do you account for the indigenous animals of (say) Australia such as wombats, kangaroos, wallabies and Tasmanian Devils? Native to Australia and nowhere else. Did they all float there on driftwood (This has actually been proposed as a solution to Australia's indigenous animal population by a Noah's flood proponent)
How did salt water fish survive the flood when there natural habitat was so diluted with fresh water and how did fresh water fish survive when there natural habitat became contaminated with the salt water of the oceans?
What did herbivorous animals eat on disembarking from the ark?
How did pandas manage to find bamboo when all vegetation had been destroyed? How did koalas find eucalyptus to eat if they disembarked in Turkey?
What did carnivorous animals eat? The dinosaurs?
Not to mention that biblical literalist who believe in the flood myth also tend to be creationists who deny evolution but have no problem with believing that the animals that left the ark evolved pretty damn quickly into the animals of today. IE, the pair of felines became the domestic moggy, the lion, cheetah, the lynx, the ocelot, the cougar and dozens of others....all in the space of a few thousand years.