martes, 29 de marzo de 2011

Early Humans Occupied South Asia Over a Million Years Ago

RECENTLY DISCOVERED ARTIFACTS IN SOUTH INDIA SUGGEST THAT EARLY HUMANS LIVED IN THE REGION MORE THAN A MILLION YEARS AGO, CONTEMPORARY WITH OTHER EARLY HUMAN POPULATIONS THAT LIVED IN AFRICA AND SOUTHWEST ASIA. The discovery may finally answer the long-standing question about when early humans migrated into South Asia, a question that has puzzled scientists for years. The artifacts, Acheulian stone cutting tools, were uncovered by a team of researchers at a site in the Kortallaiyar river basin in Attirampakkam, India. Acheulian tools are usually associated with early humans who lived between 1.6 million and 100,000 years ago in Africa and southwest Asia and, based on earlier archaeological excavations and studies, are thought to have originated in Africa around 1.6 million years ago and then spread through Eurasia later. The precise chronology, or timing, of the spread of this technology and thus their associated toolmakers through India and South Asia has remained a mystery. However, excavating at the Attirampakkam site, Shanti Pappu of the Sharma Center of Heritage Education and his team unearthed more than 3,500 quartzite stone artifacts, including cleavers, flakes, and more than 70 Acheulian handaxes datable to over 1 million years in age. Researchers were able to date the artifacts using two different proven methods. First, paleomagnetic measurements were taken of the sediments surounding the artifacts. The measurements showed a "reversed polarity" in the constitution of the sediment, which means that the sediments predated the last reversal in the Earth's magnetic pole. To narrow down the dating, researchers then applied a technique based on the decay of isotopes of aluminum and beryllium in the sediment grains over time. The isotopes in the grains decay at a predictable rate after their exposure to cosmic rays in the atmosphere are cut off following burial from successive sedimentation. The results showed that the sedimentary context of the artifacts were no younger than 1.07 years old. By association, this meant that the artifacts were the same age. States Pappu,, in the report of the findings, "based on data from controlled excavations and two independent dating methods, our ages from Attirampakkam show that the Acheulian in India is older than previously thought...........these results reveal that, during the Early Pleistocene, India [and thus by extension South Asia] was already occupied by homins [early humans] fully conversant with an Acheulian technology including handaxes and cleavers among other artifacts".* Read More: Popular archaeology:

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