There's also some idea that the more deeply embedded the fossils are the longer the Flood should have taken. Why?
For the same reason that it took longer to build the Notre Dame than it did a back yard shed. You don't get hundreds of feet of coral growth in a single year.
If the argument is that the Flood simply covered existing mountains, that could explain the fossils ON the mountaintops, yes, but the idea is that the Flood deposited all the sedimentary layers that contain fossils, and in the case of mountains this would have happened before the mountains had been raised. After the Flood, the fossil-containing strata were pushed up to become mountains, which is why the fossils are IN the mountain and not just on it.
What evidence do you have for rapid mountain building?
But this is all from the Old Earth/evolutionist point of view. From the Flood point of view all that was already there and the Flood just picked it up and buried it in this or that layer of sediment.
You are talking about a solid piece of rock hundreds of thousands of miles in area and hundreds of feet thick. Sorry, doesn't work that way. A whole, unbroken rock the size of a giant sea doesn't get moved by a flood.
If all the supposed ordering of the fossils in the geological record are in fact merely accidental effects of a Flood that simply moved around whatever was already there, then this idea that they are clues to an ancient past is an illusion, sort of like reading tea leaves. (except of course the antediluvian ancient past -- THAT you can learn about from the fossils).
Such a process wouldn't sort fossils so that they correlate to specific isotope ratios found in igneous rocks below and above them. This is what disproves your flood story. We should see a random association between isotope ratios and fossils if your scenario is true, but we don't. Instead, we see the correlation predicted by the Old Earth and No Flood scenario.
But my point of course is that it can be accounted for by the Flood followed by mountain building so that the objection that fossils within the rocks can't be explained by the Flood is in fact explained.
Re: The evidence: sorted trilobites, sorted radiometric isotopes
The trilobites are nothing more than cousins, and for whatever reason the Flood did sort sediments and creatures. You have no proof for your theory either, it IS all theory, period.
To back up what RAZD said, it isn't a theory that rock layers are sorted by their isotope content. It is an observable fact.
How does a flood magically sort rocks so that the igneous rocks towards the bottom of the stack of rocks have a higher Ar concentration than the rocks at the top? How is a flood able to sort trilobites and igneous rocks so that trilobites are always found below rocks with a specific K/Ar ratio?
We are not using radiometric dating here. We are simply measuring the isotope content in rocks which is an observable fact. How does a flood do this?
It is known that water sorts things and makes layers of sediments
It is known that the isotope content of igneous rocks is not enough to cause water to sort them by tiny tiny differences, and yet that is what we see. Therefore, those layers were not created by a single event that sorted those layers by tiny differences in Argon content.
The evidence is in the tight contacts between the layers, their flatness and straightness before tectonic deformation, the accumulation in some places of the whole sequence from Cambrian to Holocene without tectonic disturbance, the absence of any erosion on a scale that would imply conditions for a time period at that level in the geological column, the fact that the sediments cover enormous areas of geography layer after layer which would kill anything that had lived there, in other words the evidence shows deposition one layer after another, which implies deposition by an enormous amount of water over a short period of time.
If we were to show you layers that were not flat or straight would this disprove a recent global flood?