Sunday, June 23, 2013

Stone Age technological and cultural innovation accelerated by climate

EurekAlert! ^ | June 18, 2013 | Rainer Zahn

The latest archaeological excavations in southern Africa have shown that technological innovation, linked to the emergence of culture and modern behaviour, took place abruptly...
An international team of researchers has linked these pulses of innovation to the climate that prevailed in sub-Saharan Africa in that period...
The researchers have pieced together how rainfall patterns varied in southern Africa over the last 100,000 years, by analysing river delta deposits at the edge of the continent, where every millimetre of sediment core corresponds to 25 years of sedimentation. The ratio of iron (dissolved from the rocks by the water during the rains) to potassium (present in arid soils) in each of the millimetre layers is a record of the sediment carried by rivers and therefore of the rainfall throughout the whole period.
The reconstruction of the rainfall over 100,000 years shows a series of spikes that occurred between 40,000 and 80,000 years ago. These spikes show rainfall levels rising sharply over just a few decades, and falling off again soon afterwards, in a matter of centuries. This research has shown that the climate changes coincided with increases in population, activity and production of technology on the part of our ancestors, as seen in the archaeological records. In turn, the end of certain stone tool industries of the period coincides with the onset of a new, drier climate.
(Excerpt) Read more at eurekalert.org ...

T-Shirt