Indus civilisation flourished along a course abandoned by river Sutlej: Scientists

It wasn’t the “mythical Saraswati” as some wanted to believe, but the river Sutlej that had given rise to the great Indus civilisation which flourished around 4,000 years ago, a team consisting of researchers from India and the UK has found.

The findings derived from new geological evidence gathered by the international team of scientists led by Sanjeev Gupta, a geologist with Imperial College London, may have significant bearing on our understanding of how the ancient urban civilisation bloomed and doomed.

Unlike other civilisations such as the Mesopotamian or Egyptian civilisations, which came up on the banks of major rivers, the ancient Indus civilisation flourished along a course which the Sutlej river abandoned some 8,000 years ago, the scientists reported in the journal Nature Communications on Tuesday. Archaeological evidence gathered from many excavated Indus civilisation sites in India (and also in Pakistan) has shown that the ancient urban settlements came about 4,600 years ago.

“Previously it has been supposed that early urbanisation required access to perennial rivers. But the urban centres of the Indus civilisation (also known as Harappan civilisation) developed without the water provided by a big Himalayan river,” said Gupta.

Archaeological evidence gathered from many excavated Indus civilisation sites has shown that the ancient urban settlements came about 4,600 years ago.

Through meticulously carried out sediment studies and remote sensing, the scientists identified that the present-day Ghaggar river (it is called Hakra in Pakistan), which is a seasonal river, flows through this former course of Sutlej. “But our detailed dating of the river sediments show that the river was not flowing there at the time of the Indus settlements -- the Sutlej had diverted several thousand years before the development of the urban Indus civilisation,” said Gupta.

The study calls into question the contention of a section of archaeologists that these ancient urban settlements might have developed along the “lost” river of Saraswati. It may debunk some of the arguments forwarded by them to “establish” it was indeed Saraswati, not Ghaggar, that supported the ancient civilisation. For instance, the proponents of Saraswati earlier argued that there was enough geological and sedimentary evidence to show that the river that fed the Indus civilisation carried glacier headwaters. Ghaggar, they contested, could not have been this river as it originated from the Shiwaliks in the foothills of the Himalayas.

The new study has emphatically resolved this mystery because the Sutlej did carry geochemical signatures of glacial origins.

“Our findings are contrary to earlier statements of scholars, but they did not have the hard scientific data. Our dating evidence is very clear,” Gupta told BusinessLine from London.

“Many believed that it was the death of a river that led to the collapse of the civilisation. But what we find is that it was the demise of a river (by changing of its course) that helped a civilisation to come up and flourish,” said Rajiv Sinha, a professor of earth sciences at IIT Kanpur, who contributed to the study. “In that sense this is a major turning point in the understanding of our past,” Sinha said.

But, the scientists argued that the big Himalayan river did beget the Indus civilisation in some ways. “When the river diverted, it left a former channel in the landscape which was a topographic low. This served to capture and concentrate monsoon-fed river flow and contained excellent soils for agriculture. Thus the Sutlej formed the environmental template for the civilisation in this region,” said Gupta.

This was further borne out by the fact that some of these ancient settlements – such as Banawali in Fatehabad district of Haryana -- were actually built within the paleochannel and if the river was active they would have had been destroyed by river floods.

“This is a very good study which used two different techniques of geochemical fingerprinting with a large number of samples,” said Suvret Kher, an Indian geologist, who is well-known for his blogs on the scientific subject.

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