The discovery of Acheulian tools no younger than one million years, and possibly as old as 1.5 million years, in Tamil Nadu overturns the current thinking that hominins or early humans lived in India merely 0.6 million to 0.5 million years ago. The exciting finds are from a site at Attirampakkam, in the Kortallayar River basin, about 60 km northwest of Chennai. Previous age estimates indicated that hominins who moved out of Africa dispersed across Asia and Europe around the same time. This was inconsistent with the widely accepted current theories of early human migration from Africa to Asia. By dating the artefacts as at least one million years old, a paper published online in Science (“Early Pleistocene presence of Acheulian hominins in South India” by Shanti Pappu et al., March 25, 2011) comes close to placing them in sync with the migration of early humans from Africa to the rest of the world through Asia. The latest study used two dating methods – palaeomagentism to date the sediments from where the tools were recovered, and aluminum-beryllium isotope technique to date six artefacts. Combining the two techniques helped make the dating robust.
Attirampakkam was identified by the British geologist Robert Bruce Foote in 1863. The Indian researchers took nearly a decade of holistic study of the site to understand the archaeology in relation to paleo-environment. Among the more than 3,500 quartzite tools recovered from the site, the most common ones were the oval and tear-drop shaped bifacial hand-axes, cleavers, and small fakes (small chipped stones). Quite a number of tools discovered at the lowest buried Acheulian levels indicate that they were brought from elsewhere and only the final shaping was done at Attirampakkam. This is not unexpected: hominins using Acheulian tools were highly mobile.