Ignore dendrochronology. They have a continuous calendar going back that far. When they finally pull up a post from a building down in the oxygen-free depths of the Black Sea they will be able to date it to the year the tree was cut.
I did a quick check, and I see that you are correct. I did not think that the time line had extended that far back yet, but I see that in Europe, it has been extended back to over 12,000 years. Do you know if it has been applied to the Agassiz event?
...they will be able to date it to the year the tree was cut.Only if there is bark on the tree.