So it appears that as per my OP question, what is being dated in order to determine the time the organism was deposited is the intrusive igneous rock which is above the fossil.
What hubris! How can you post stuff like that, Buzsaw? Your original post did not even hint at dating of igneous rock. You weren't even close.
So it appears that what would ultimately determine the age of the fossil is whether the plate tectonic activity was relatively sudden via catastrophe or over the millions of years, inch by inch.
What think you?
I think you've demonstrated how incredibly difficult it is to get anywhere with one foot nailed to the ground.
If a fossil is between two layers, how would your assumptions affect dating of the fossil? I'm asking that you explain how the catastrophe model would affect the dating of each of the two layers. In your explanation, please at least attempt to identify the mechanisms that affect layer dating.
Some hints. The birth date of igneous rock is assumed to be the date the rock solidified from lava. Please remember take into account the direction in which you want scientists dates to be wrong.