Age· The columns of time

Greenlandian

11.7 ka → 6,237 BCE

The Greenlandian, from 11,700 to 8,200 years ago, is the first age of the Holocene, defined in a Greenland ice core: warming set in, agriculture began and the Sahara was grassland.

First age of the Holocene, defined in a Greenland ice core, in which warming becomes established, agriculture begins and the Sahara carries grassland vegetation.

What the evidence shows

It begins with the Holocene, at a layer counted in the Greenland core NGRIP2: 11,700 years before the year 2000, a limit read in ice and not in rock. By at least 11,500 years ago, a few centuries after that limit, populations of the Fertile Crescent were tending plants and animals still wild in appearance, sowing what they had harvested and keeping herds nearby, well before any of these species showed the least morphological character of domestication. At the same time, an oscillation of the Earth's orbit shifts the summer monsoon north and, from about 11,000 years, the African Humid Period covers the Sahara with grassland and lakes, with hippopotamuses and fish, and later cattle herders whose rock paintings survive.

Bounds and conventions

Counting the ice layers dates the limit to the year, a precision no rock section allows, but that precision belongs to the core and not to the phenomenon: the warming it marks was not simultaneous everywhere. The beginning of agriculture is a process spread over several centuries and several regions, and its dating depends on the definition adopted for domestication.

GSSP NGRIP2, 11,700 years b2k.