[tied] Dating Sea Level Changes

----- Original Message -----

From: John Croft

To: cybalist@egroups.com

Sent: Wednesday, August 23, 2000 2:04 AM

Subject: [tied] Re: Sea Level and the Entry of Greek.

 

 

John,

 

Do you happen to know more about the dates you quote? Are they radiocarbon? calibrated radiocarbon? other? AFAIK the beginning of the Subboreal phase is dated at ca. 3830 BC in calendar-year terms (based on calibrated radiocarbon datings = ca. 3150 BC uncalibrated). In northern Europe the cooling was quite significant, with heavier snowfalls in winter and the weather generally less stable than during the Atlantic phase. Forests gradually gave way to forest-steppe with numerous open grasslands, and whatever the role of anthropogenic factors, climatic deterioration certainly accelerated the process of deforestation.

 

Piotr

 

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John wrote:

3,200 BCE is also roughly the period of the Early Dynastic stories of the Flood of the Gilgamesh Epic, associated with the king of the 5th Dynasty of the Sumerian King List - Utunapishtim.  From 5,500 BCE to 3,200 BCE according to the latest evidence I have seen seas were up to 5 metres higher than they have been in the recent past.  This was the "Atlantic Phase" of post glacial climates when temperatures were
significantly warmer than they have been any time since (except for with the current anthropogenic global warming).

Sea levels began to fall after 3,200 causing coastlines to retreat.  This is found in "perched" or "benchline beaches" around the world, in the emergence of the Fens in Norfolk and the Polders in Holland, together with the appearance of land once under water on major river deltas (Mesopotamia, Mississippi etc).  The change in levels seems to have been largely due to the final dissappearance of the small Fenno Sacndian glacier, and the disappearance of the remnant Labrador and North Western Laurentide glaciers, together with thermal expansion of the oceans.

The cooling that followed, and the retreat of beaches that occurred as sea levels fell, saw a worsening of conditions across Northern Eurasia.  The response was

1. a reversal of movements of people from the south to the north that had been occurring for millennia.
2. adaptation of cultures that didn't move for conditions of greater cold. <snip>