Climate stage· The columns of time

Saalian glacial

191 ka → 130 ka

Sixty thousand years of cold, and the longest glacial stretch our species had faced by then. Ice sheets reach far into northern Europe, and the Sahara becomes a barrier rather than a corridor.

What the evidence shows

Named after the Saale, the German river whose valley records the extent of the ice, this stage covers MIS 6. For a species still confined to Africa, its consequence is a closed door. A green Sahara period closes in two to three millennia, the desert reasserts itself, and habitats that had been continuous break into fragments; through a long glacial the routes north stay shut. The interglacial that follows opens them again, which is why the Eemian matters so much on a timeline about human movement.

Bounds and conventions

The name is regional, taken from northern European glacial geology, while the boundaries drawn here come from the global isotope curve. The two do not align exactly, and where they disagree this timeline follows the curve, which at least applies everywhere.

MIS 6.

Sources

  1. Lisiecki, L. E., Raymo, M. E. (2005). A Pliocene-Pleistocene stack of 57 globally distributed benthic δ18O records. Paleoceanography 20, PA1003.
  2. Larrasoaña, J. C., Roberts, A. P., Rohling, E. J. (2013). Dynamics of Green Sahara Periods and Their Role in Hominin Evolution. PLoS ONE 8(10), e76514.
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Elsewhere on the column

A period boundary is a decision before it is a date. Where the two disagree, this entry says which is which.