The Würm glacier went through three phases: a cold one from 71,000 to 60,000 years ago (marine isotope stage 4), a warm one from 60,000 to 25,000 (MIS 3), and another cold period from 25,000 to 12,000 (MIS 2).
During the warm period, sea levels were still at least 200' (60 meters) below current levels, and often 300' (90 meters) because ice sheets trapped so much of the available water. In the second cold period, around 21,000 years ago, waters were 410' (125 meters) lower than today.
Within the middle phase, decade-long periods of relative warmth and chill alternated. They fell into four longer-term warm eras which ended when glaciers calved, sending cold water into the oceans and lowering temperatures. The warm times, when the Greenland ice contained higher concentrations of the oxygen18 isotope, peaked 58,000, 53,000, 47,000, and 39,000 years ago.
Cro-Magnon tools show humans reacted to these changes in their environments. No one will hazard exact chronologies because the effects of the climate varied by location, and human responses often were modulated by other factors.
The first phase occurred at least 90,000 years ago in the warm period between the Riss and Würm glaciers. Homo sapiens left remains at Qafzeh and Skh l in the Levant with technology no different than that of the Neanderthals. There’s no evidence they moved farther.
Another group began moving as the climate warmed some during the Würm glacier about 60,000 years ago. Jean-Jacques Hublin said, they moved north into central Europe, arrived at Bohunice in Moravia about 48,000 years ago. They traveled east into central Asia where they reached the Altai mountains around 47,000 years ago. According to Ted Goebel they used a flat-faced technology.
When they encountered the colder conditions of the Danube, Jirí Svoboda said, they developed a new technology, the Aurignacian. The most important trait defining their toolkit was that, instead of a few general purpose tools, men made some for specific purposes. They also began working with bone and antler. They learned to split it as they had earlier mastered splitting rock.
From there, Aurignacian tools moved west, tracking south of the cold front. They appeared in the Bacho Kiro cave in Bulgaria 37,900 years ago, France 37,800 years ago and northern Spain about 30,000 years ago. The tools didn’t penetrate southern Spain until 27,500 years ago.
The technology also moved back south toward the Zagros mountains along the modern boundary between Iran and Iraq. Yafteh cave was occupied between 30,000 and 35,000 years ago.
The technology had disappeared by 27,000 years ago. The map below shows the distribution of important sides in Europe.
In the east, Goebel said the migrants moved from the Zagros mountains across the uplands of central Asia to the Altai mountains in southwestern Siberia. Next they moved across Siberia past Lake Baikal through the Trans-Baikal mountains 42,000 years ago. From there they passed into Mongolia sometime between 41,000 and 43,000 years ago. Some moved south into northern China about 30,000 years ago where the encountered other people who had moved through southeast Asia.
They made an independent adaptation to the cold that used bone, antler and ivory for points, awls, and needles. They made fewer personal ornaments than the Aurignacians, and less evidence of ochre has been found.
Notes:
Goebel, Ted. "The Overland Dispersal of Modern Humans to Eastern Asia," in Kaifu. He has a good map showing the location of archaeological sites that mark the move east.
Hublin, Jean-Jacques. "The Modern Human Colonization of Western Eurasia: When and Where?", Quaternary Science Reviews 118:194-210:2015. He has a good chart showing phases of the Aurignacian with a time line showing coinciding changes in levels of oxygen18 isotopes in Greenland ice cores.
Kaifu, Yousuke, et alia. Emergence and Diversity of Modern Human Behavior in Paleolithic Asia, 2015.
Siddall, M., E. J. Rohling, W. G. Thompson, and C. Waelbroeck. "Marine Isotope Stage 3 Sea Level Fluctuations: Data Synthesis and New Outlook," Reviews of Geophysics, December 2008. The warm periods were Dansgaard-Oeschger events, the cool ones were Heinrich events, the four eras were bond cycles.
Svoboda, Jirí. "Early Modern Human Dispersal in Central and Eastern Europe," in Kaifu.
Graphics: Hugh Charles Parker, "Aurignacian Culture Map," uploaded to Wikimedia Commons, 2 June 2011.
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