Why do you need 1700 years of slow deposits before a single event with mass deposits?
You don't need that, I just feel on the balance of probabilities that is what the evidence is showing. The evidence seems to show lower sedimentary deposits as having a worldwide wetlands type fauna and flora (not exclusively but mainly). This worldwide layer seems to show signs of increasing biological debris over time, and also increasing oxygen levels over time. This layer is followed by a worldwide extinction event during a volcanic phase, followed by a proliferation of dry climate fossils and lowering oxygen levels, and highly restricted peat development.
To me, this is exactly what you would expect from the biblical perspective. You would expect a world highly conducive to life (900 year lifespans), you would expect the sudden appearance of worldwide vegetation to cause increasing oxygenation and fertilisation over time, because vegetation does grow in soil, but grows even better in soil combined with dead vegetation (fertilised). You would then have a sudden drowning of all vegetation, causing spikes in methane levels, and marine fungal spikes. This rotting vegetation would be exposed as flood waters recede, causing a non-marine fungal spike. This would be followed by an earth full of silt, with vegetation battling to return to previous levels. Oxygen levels would drop until a new equilibrium is reached as vegetation returns to a maximum in the new environment ( we may only be reaching that equilibrium now).
This is what science confirms around the so-called P-T boundary, exactly what we would expect from a logical projection of a world wide flood drowning a fertile oxygenated world followed by humans of stunted growth (100 year life-spans compared to 900 year life-spans). To place the biblical great death event together with the scientific great death event seems like the most logical thing to do.