I do not see the relevance of the area of deposition of the Mississippi delta to EE.

The problem is this. The contributory area that contributes water and sediment to the delta covers roughly half the area of the United States. Let us say, and I do not know the real number, it is a million square mile of surface area, while the surface area of deposition is say one square mile (depositional slope) of area where final deposition is occurring. It is simply a 1,000,000 to 1 ratio of where it was eroded from to where it is being deposited. One would expect a relatively rapid depositional growth of the delta if the area contributing material is a million time greater than the area receiving the material.

If you want to find out about things that contribute to growth of the Earth, you need to go to the final resting place of material that accumulate from space. These only occur on the abyssal plains of the major oceans far away from the contributions from eroding continents. Eroding continents add additional material to that contributed from space for a couple of hundred mile out from shore. Beyond that only what falls from the sky ends up distributed on the abyssal plains.

Eroding and re-depositing shore lines (and deltas) do play an important role though. They are creating the new continental land areas of the future atop the basaltic crust of the ocean floors. After many repeat cycles of erosion and deposition there will again be a few pulsed expansions of the Earth that increase the radius, lower the ocean levels, expose some areas of the sea floors, and provide more surface areas to commence the process again. Just think of the head cutting of the Mississippi river if the ocean levels suddenly dropped several feet. It would occur in all of the major rivers on Earth that are now dominated by silted up deltas.

I suppose that the formation of deltas does have some regard or reference to EE/GE. They would be indicative of periods of time between pulsed expansions of the Earth, and also indicative of times when sea levels are rising. These rising sea levels mean that silt laden waters drop their load inland atop the deltas, or on the exposed front face. However during pulsed expansions deltas will have head cutting channels while dropping their load of sediment beyond the front face of the delta thus forming the base of new deltas for the time after head cutting slows and stops.

An interesting cyclicity in all of this, or do they call it the chaos of complex entanglements.

Climate, expansions, erosions, depositions and random chance all affecting geology.