December 04, 2008

Middle Stone age started 276,000 years ago

It is interesting that fairly modern tools were found so much earlier than previously thought. Whether anatomically modern humans existed back then is yet to be determined. This result shows that different levels of technological sophistication were to be found at the same point in time: mankind back then was not one species with one level of culture. And, indeed the earliest Homo sapiens, Omo I and II, were followed tens of thousands years later by Herto who was more "archaic" anatomically. Culture and anatomy do not go hand in hand.

Geology doi:10.1130/G25213A.1

Diachronous dawn of Africa's Middle Stone Age: New 40Ar/39Ar ages from the Ethiopian Rift

Leah E. Morgan1 and Paul R. Renne


The Middle Stone Age (MSA) of Africa, like the Middle Paleolithic of Europe, is thought to represent a time period wherein toolmakers acquired significant increases in cognitive abilities and physical dexterity. Existing data fail to resolve whether the MSA emerged gradually, abruptly, or discontinuously, and whether this industry reflects the activity of Homo sapiens. Here we present new 40Ar/39Ar geochronological data revealing that advanced MSA archaeology at two sites in the main Ethiopian Rift is older than 276 ka, much older than technologically comparable MSA archaeology from elsewhere. An age of 183 ka for a unit farther upsection, along with the technological stasis observed throughout the section, indicates that similar technology was used here for ~93 ka. These results suggest that MSA technology evolved asynchronously in different places, and challenge the notion of a distinct time line for either the appearance of the MSA or the disappearance of the earlier Acheulean. These and other recent results indicate that the oldest known MSA consistently predates fossil evidence for the earliest Homo sapiens.


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