Sub-stage· The columns of time
Greenlandian
11.7 ka → 6,237 BCE
The first age of our epoch, running from its floor to a sharp drying eight thousand two hundred years ago. Farming spreads through it, and the first villages with it.
What the evidence shows
Its top is the 8.2 kiloyear event: an abrupt cooling and drying recorded across the northern hemisphere, most plausibly caused by the sudden drainage of enormous glacial lakes into the North Atlantic. That boundary is one of the two new golden spikes ratified in 2018; the one at its base is the Holocene's own, and older. Both are read in ice rather than in rock, which is unusual for a geological age and says something about how recent it is.
Bounds and conventions
Ratified, and therefore official, but recent enough that some geologists question whether such fine divisions of a single epoch are useful at all. The debate is about the value of the subdivision, not about the reality of the events it uses as markers.
NGRIP2 GSSP, 11,700 years b2k.