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I read your analysis and your assumptions seem valid enough. I would just add a couple of cautions. It seems as though your discussion is about the geolgoic history over the past 5,000,000 years (since the beginning of the Pliocene). But if you are going to tie in human inhabitation and archeology, you effectively are referring to the last ice age, which peaked about 20,000 years ago and petered out by about 12,000 years ago. (Keep in mind, I am not talking about "mini-ice ages" which are abundant in the microfossil record - I am talking about the formation and loss of continental ice sheets.)

When sea level is eustatically low, the stratigraphic record in the Gulf of Mexico records an greatly increased influx of sedimentation. This is due, in part, to increased erosion caused by the increased differential between the highstanding land and the ocean lowstand (nature abhors a vaccuum, and constantly tries to tear down the high points and fill up the low points).

Another factor to consider is that when continental ice sheets form, the weather patterns are changed. In the last glacial stage, the dry "horse latitudes" moved south toward the equator. As the ice age waned, they moved back to the north. This means that some areas which are very wet today, were relatively dry 20,000 years ago, and visa-versa. I frankly don't know how this affected rainfall patterns over continental North America, Central America, and northern South America. It just means that some of your speculative assumptions could be considerabley off - but I am not knocking you for the effort! I am just saying that there is a high degree of uncertainty involved.

Thanks again for your thought-provoking post.

"This is due, in part, to increased erosion caused by the increased differential between the highstanding land and the ocean lowstand (nature abhors a vaccuum, and constantly tries to tear down the high points and fill up the low points)."

I agree. I have read that one guy compares the Nile Vally to the Grand Canyon during the Ice Age due to this 'lower water level effect' that must have created deep canyons way back up past Cairo on the Nile. This all occurred in human history and may be recorded somewhere.(?)

I have some 7,000 year old wood that came from the Santa Rosa Sound Florida that was 'high and dry' at that time. I just wonder why it was suddenly flooded 7,000 years ago if the Gulf Of Mexico was not 'dammed' to some degree, or totally. BTY, all the calculations in post #42 were done by a friend of my son, not me.