Given that the bottom of the Atlantic is dominated by igneous rock, we would only expect a skim layer of fossiliferous sediment. But you have big problems there as well. The outflow of basalt from the mid-Atlantic ridges preserves a geomagnetic record of the earth’s field stretching back millions of years, showing the history of magnetic strength and reversals.
Of course, creationists have cooked up a cockamamie response to this, and it is kinda a doozy. Freely decaying electric currents, a sort of white hot superconductivity in a resistive medium, is supposed to be responsible for the earth’s magnetic field, in violation of pretty much every formulation of electromagnetic law possible from ohm’s law up. The point of that is to then finangle rapid magnetic reversals, just like Moses said, particularly during the flood. What - an inertial current reverses??? How? Why? Apperently, in YEC two nonsenses make a sense. And to what purpose or reason? To deceive people into thinking the earth is old? Because there is no other reason offered. For anyone foolish enough to buy into this, please know that I’m a time traveler from the future, because that has more credibility.
I’m going with the geologist over the apologist on this one. Most states have their own public core repository. Instead of us itemizing the tens of thousands of cores available, why don’t you tell us some specific formations you think have been missed? Oh yeah, more apologetic hand waving.
While you are at it, how much of the antediluvian world do you think was devoid of pollinating plants, no coned or flowering trees, no shrubs, no grass, no wildflowers?