Age· The columns of time

Greenlandian

11.7 ka → 6,237 BCE

The first age of the Holocene, defined in a Greenland ice core: the world warms for good, farming begins, and the Sahara is grassland.

What the evidence shows

It begins where the Holocene does, on a layer counted out in the NGRIP2 Greenland core: 11,700 years back from the year 2000, a boundary read in ice, not in rock. The world it opens is warming out of the last glaciation. By at least 11,500 years ago, within a couple of centuries of that boundary, people across the Fertile Crescent are tending plants and animals that still look entirely wild, sowing what they had gathered and keeping herds close, long before any of those species shows a physical sign of domestication. Meanwhile a wobble in the Earth's orbit pulls the summer monsoon north, and from about 11,000 years ago the Sahara greens: grassland and lakes, hippopotamuses and fish, and in time cattle herders who painted its rock.

Bounds and conventions

Counting the ice layers dates the boundary to the year, a precision no rock section can offer, but that precision belongs to the core and not to the world: the warming it marks was not simultaneous everywhere. The beginning of agriculture is a process spread over centuries and several regions, and its date depends on what one agrees to call domestication.

NGRIP2 GSSP, 11,700 years b2k.

Sources

1. Cohen, K. M., Finney, S. C., Gibbard, P. L., Fan, J.-X. (2013). The ICS International Chronostratigraphic Chart. Episodes 36(3), 199–204, mise à jour continue, voir Cohen et al. (2025), Episodes.
2. Walker, M., Head, M. J., Berkelhammer, M., et al. (2018). Formal ratification of the subdivision of the Holocene Series/Epoch: two new GSSPs and three new stages/subseries. Episodes 41(4), 213–223.
3. Zeder (2011), Current Anthropology · The origins of agriculture in the Near East
4. Kröpelin et al. (2008), Science · Climate-driven ecosystem succession in the Sahara: the past 6000 years