Thursday, September 03, 2009

European Hand Axes Almost a Million Years Old

New dating has revealed that hand axes from two sites in Spain are close to a million years old. Yahoo UK reports:

Gary Scott and Luis Gibert of the Berkeley Geochronology Center in Berkeley, California applied a technique called magnetostratigraphy to determine that the hatchets were in fact crafted between 760,000 and 900,000 years ago.

Magnetostratigraphy is based on the periodic reversal of Earth's magnetic field.

Acting like tiny compasses, fine-grained magnetic minerals in the tools contain a record of the polarity at the time they were used. Once buried in sediment, the polarity is preserved.

"The age (of the axes) must be Early Pleistocene, the most recent period dominated by reverse polarity, 1.78-to-0.78 million years ago," the researchers concluded.

Magnetostratigraphy is also known as palaeomagnetism. It was always suspected that the hand axe use was there, it is just that there has been no concrete evidence. This changes that. There is a tool assemblage called the "Mousterian of Acheulean Tradition," that is practiced by Neandertals in southern Europe and Gibraltar but it is more advanced than the typical hand axes you find associated with Homo erectus. The transition likely took place much after this, in southern Europe.

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