Research press release


Nature Communications

Archaeology: The Indus Civilisation and the lost river



今回、Sanjeev Guptaたちの研究グループは、これらの居住地において主要な古河川(古い川の名残)の証拠を発見した。この古河川は、サトレジ川の旧流路にあたる。Guptaたちは、この古河川の堆積物の年代測定を行い、約8000年前にサトレジ川の流路が変わったことを明らかにした。また、居住地は、これまで一般的に考えられていたようにヒマラヤ山脈を水源とする大きな現河川に隣接して発達しておらず、むしろ古い川の名残に沿って繁栄し、発達し続けたことも今回の研究で明らかになった。Guptaたちは、サトレジ川の流路が変わったことで洪水が減り、季節的降雨によって上流の渓谷が水源になったことがともに寄与して、この環境でのインダス文明の成功につながったと考えている。

The mystery of how an early civilisation in northwest India and Pakistan thrived without a river source may have been solved in a study published in Nature Communications this week. These findings challenge our understanding of how early civilisations developed.

Early urban society settlements locations are thought to have been influenced by river migration. However, the largest concentration of the Bronze Age Indus Civilisation (who lived around 4,600-3,900 years ago) settlements were located between the Ganges-Yamuna and Indus river systems in India and Pakistan, far from major active rivers. How these settlements prospered away from rivers had remained unclear.

Sanjeev Gupta and colleagues find evidence of a major palaeochannel (the remnants of an ancient river) through these settlements, which was once part of the present-day Sutlej River. By dating the sediments from this ancient channel, they find that 8,000 years ago the river changed course. They show that the settlements did not develop adjacent to a large active river fed from the Himalaya as has commonly been believed. Instead the settlements thrived and continued to develop along the relict palaeochannel. The authors suggest that the diversion of the river led to reduced flooding, and that seasonal rains provided a water source in the upper valley, which together contributed to the success of the Indus Civilisation in this setting.

doi: 10.1038/s41467-017-01643-9


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