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I recently had a significant breakthrough on the dating. Over the years I have been attempting to associate the various shore-line terraces which show no bays, but the glacioisostatic issues owing to raised shorelines of the forbulge in NJ, MD and VA caused me to abandon that approach. This week, another temporal measuring stick has been uncovered, not that I was the first to notice (see Soller, USGS Professional paper 1466-A, 1988, ). The Cape Fear Arch in NC has been rising by as much as 0.6mm a year for 2.5 million years. One side effect is that the Cape Fear River has been migrating laterally to the south and west as its bed is tilted. I had assumed that the entire area of braided -channel surface along the river was recent, and that's why there are no Carolina bays. At each glacial maxima over the intervening 2.5 million years, there has been a deep incision as the sea level drops. Then, when it returns during the interglacials a terrace is formed. All the terraces except the most recent -called the Wando - have bays on the surface. There are no indications that braided fluvial deposits ever existed on those older surfaces. They were reworked by some mechanism which masked the braiding.

Now here's the kicker - the Wando is known to have been created during the Sangamon interglacial, 130 to 70ky ago. No bays. No bays during the LGM, with all those powerful winds! ;). Just a ragged, braided surface looking significantly different than the higher terraces to the north and east. I interpret this to be proof positive that the bays are not created by a generic wind and wave process across all sandy surfaces in the area. At the same time, it mandates that they were created prior to 130Ka - before the "Penultimate" Illinoian Glaciation. Additionally, the next terrace above the Wando - called the Socastee - is dated as being created during the previous interglacial. Since this is fully covered with bays, right up to the incision that dropped down to the Wando, it provides an upper constraint on formation of ~200ka during the interglacial prior the the Illinoian maximum. 

I'm just following the data, so I am not concerned that the proposed date for my Saginaw Impact is moved back to between 200ka and 130ka.

Here is a LiDAR image:
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