Euxine, II

Neolithic farms spread with Neolithic farmers. At two points before 5500 BC – before the urbanisations – those farms paused. A former blog, in 2006, had discussed these pauses, in context of the book Noah's Flood.

Here is a study measuring sea surface salinity not far west of the Dardanelles. As expected, this water gets fresher as the ice melted, starting 9000 BC (after Younger Dryas) and stabilizing again 3000 BC. This desalinization trend is punctuated with two sharper drop-offs.

One drop is at some span within the longer range 5756-5621 BC. Below that, another drop within a range 6492-6364 BC. The spans coincide with the melting of the Laurentide… in Canada, the earlier stage of which also drained Agassiz. The lake drained 6500ish BC – suddenly; and the whole sheet was melted I’m guessing more gradually over the late 5700s.

The former drainage chilled worldwide temperatures; which, I presume, delayed the final melting of the rest of the ice. The harsh 6400s BC flood and ensuing winter further retarded development of the nascent Neolithic settlements, over 6400-6200 BC.

Back to the north Aegaean: here is a circulation between freshwater from the top of the Black Sea, draining southwest, and denser saltwater flowing back northeast along the seafloor. To this day the Euxine is sharply differentiated with a somewhat fresh and fishy top, over a lifeless dead-sea floor.

So, the abstract: “The meltwater events point to an increased outflow of low salinity water from the Black Sea”.

I wonder that the rising of waters in the Atlantic, to the west of the Med, should correlate with the outflow of Euxine water, from its east. As I read the PDF, it turns out the Euxine was already (relative to the Med) full 9100-7200 BC and spilling westward (lowering the north Aegaean salinity) 6800 BC. William Ryan, whom I'd cited 2006, was wrong!

The Mesolithic waterfall from the Euxine, over millennia, eroded the straits. After water levels rose sufficiently in the Med – much more from Canada than from Pontus – the two levels reached an equilibrium. This ended the waterfall; instead, creating the two-way current seen today. All that shook out around 6400 BC.

It happens that the shorelines in the Euxine are shallow. A small rise in sealevel can mean a large loss of lakeshore. Also, the new water starting 6400 BC was salt. Med-water was by then less salty than it had been; but still much saltier than native Euxine water, and it came over too fast for the fisheries to adapt.

The next, 5600 BC, rise in seawater was also abrupt. They say it was less abrupt than 6400 BC, and that it didn’t change the weather this time. It still would have disrupted shore life along the rugged Med and – more so – shallow Pontus.

The “Noah’s Flood” hypothesis, I gather, still stands. Also: starting 6200 BC, Caucasian Hunter Gatherers hit the northern rivers, as far as Samara. Here and now was established the CHG / EHG(=ANE) boundary; which had become a mixed, consistent culture as of 4500 BC - an Indo-Hittite culture. The Anatolians and the Maykops weren't here yet, but they're on the horizon.